slightly frustrated - Page 94

rotating bitmaps. In code.

- by Marco van de Voort

Is there a faster way to rotate a large bitmap by 90 or 270 degrees than simply doing a nested loop with inverted coordinates? The bitmaps are 8bpp and typically 2048*2400*8bpp Currently I do this by simply copying with argument inversion, roughly (pseudo code: for x = 0 to 2048-1 for y = 0 to 2048-1 dest[x][y]=src[y][x]; (In reality I do it with pointers, for a bit more speed, but that is roughly the same magnitude) GDI is quite slow with large images, and GPU load/store times for textures (GF7 cards) are in the same magnitude as the current CPU time. Any tips, pointers? An in-place algorithm would even be better, but speed is more important than being in-place. Target is Delphi, but it is more an algorithmic question. SSE(2) vectorization no problem, it is a big enough problem for me to code it in assembler Duplicates How do you rotate a two dimensional array?. Follow up to Nils' answer Image 2048x2700 - 2700x2048 Compiler Turbo Explorer 2006 with optimization on. Windows: Power scheme set to "Always on". (important!!!!) Machine: Core2 6600 (2.4 GHz) time with old routine: 32ms (step 1) time with stepsize 8 : 12ms time with stepsize 16 : 10ms time with stepsize 32+ : 9ms Meanwhile I also tested on a Athlon 64 X2 (5200+ iirc), and the speed up there was slightly more than a factor four (80 to 19 ms). The speed up is well worth it, thanks. Maybe that during the summer months I'll torture myself with a SSE(2) version. However I already thought about how to tackle that, and I think I'll run out of SSE2 registers for an straight implementation: for n:=0 to 7 do begin load r0, <source+n*rowsize> shift byte from r0 into r1 shift byte from r0 into r2 .. shift byte from r0 into r8 end; store r1, <target> store r2, <target+1*<rowsize> .. store r8, <target+7*<rowsize> So 8x8 needs 9 registers, but 32-bits SSE only has 8. Anyway that is something for the summer months :-) Note that the pointer thing is something that I do out of instinct, but it could be there is actually something to it, if your dimensions are not hardcoded, the compiler can't turn the mul into a shift. While muls an sich are cheap nowadays, they also generate more register pressure afaik. The code (validated by subtracting result from the "naieve" rotate1 implementation): const stepsize = 32; procedure rotatealign(Source: tbw8image; Target:tbw8image); var stepsx,stepsy,restx,resty : Integer; RowPitchSource, RowPitchTarget : Integer; pSource, pTarget,ps1,ps2 : pchar; x,y,i,j: integer; rpstep : integer; begin RowPitchSource := source.RowPitch; // bytes to jump to next line. Can be negative (includes alignment) RowPitchTarget := target.RowPitch; rpstep:=RowPitchTarget*stepsize; stepsx:=source.ImageWidth div stepsize; stepsy:=source.ImageHeight div stepsize; // check if mod 16=0 here for both dimensions, if so -> SSE2. for y := 0 to stepsy - 1 do begin psource:=source.GetImagePointer(0,y*stepsize); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(target.imagewidth-(y+1)*stepsize,0); for x := 0 to stepsx - 1 do begin for i := 0 to stepsize - 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[stepsize-1-i]; // (maxx-i,0); for j := 0 to stepsize - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; inc(psource,stepsize); inc(ptarget,rpstep); end; end; // 3 more areas to do, with dimensions // - stepsy*stepsize * restx // right most column of restx width // - stepsx*stepsize * resty // bottom row with resty height // - restx*resty // bottom-right rectangle. restx:=source.ImageWidth mod stepsize; // typically zero because width is // typically 1024 or 2048 resty:=source.Imageheight mod stepsize; if restx>0 then begin // one loop less, since we know this fits in one line of "blocks" psource:=source.GetImagePointer(source.ImageWidth-restx,0); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(Target.imagewidth-stepsize,Target.imageheight-restx); for y := 0 to stepsy - 1 do begin for i := 0 to stepsize - 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[stepsize-1-i]; // (maxx-i,0); for j := 0 to restx - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; inc(psource,stepsize*RowPitchSource); dec(ptarget,stepsize); end; end; if resty>0 then begin // one loop less, since we know this fits in one line of "blocks" psource:=source.GetImagePointer(0,source.ImageHeight-resty); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(0,0); for x := 0 to stepsx - 1 do begin for i := 0 to resty- 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[resty-1-i]; // (maxx-i,0); for j := 0 to stepsize - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; inc(psource,stepsize); inc(ptarget,rpstep); end; end; if (resty>0) and (restx>0) then begin // another loop less, since only one block psource:=source.GetImagePointer(source.ImageWidth-restx,source.ImageHeight-resty); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(0,target.ImageHeight-restx); for i := 0 to resty- 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[resty-1-i]; // (maxx-i,0); for j := 0 to restx - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; end; end;

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posting multiple radio button values to mysql using "foreach"

- by jeansymolanza

i have adjusted my code slightly but i am still having difficulty posting it to the table. could someone please provide me with an example of the foreach array? form page <div style="padding: 15px;"> <span class="loginfail" style="font-size:24px; font-weight: bold">Notifications</span><p> <?php include("progress_insertcomment.php"); ?> <?php // Make a MySQL Connection mysql_select_db("speedycm_data") or die(mysql_error()); $query_comment = "select * from tbl_alert order by id desc limit 1"; $comment = mysql_query($query_comment, $speedycms) or die(mysql_error()); $row_comment = mysql_fetch_assoc($comment); $totalRows_comment = mysql_num_rows($comment); ?>  <form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>"> <span id="sprytextarea1"> <textarea id='comment' name="comment" style="height: 75px; width:330px;"><?php echo $row_comment['comment']; ?></textarea> </span> <p> <button type="submit">Add</button> <input type="hidden" name="notc" value="1"/> </form>  <form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>"> <table border="0" cellspacing="2" cellpadding="2"> <?php if ( $row_comment == 0 ) { echo "<span style='font-size: 11px;'>No current alerts.</span>"; } else { // Get all the data from the "example" table $result = mysql_query("SELECT * FROM tbl_alert ORDER BY id DESC") or die(mysql_error()); while($rows=mysql_fetch_array($result)){ ?> <tr> <td> <?php echo "<div class='bubble'><div class='pimped'> <blockquote>" . $rows['comment'] . " </blockquote></div> <cite><strong>" . $rows['user'] . "</strong> @ " . $rows['date'] . "</cite> <span style='font-size: 10px;'> <p> <a href='editalert.php?id=". $rows['id'] ."' class='form' >Edit</a> • <a href='deletealert.php?id=". $rows['id'] ."' class='form'>Delete</a> </span> </div> "; ?> </td> <td valign="top" align="center"><div style="padding-left: 30px;"><span style="font-size: 10px;">Completed?</span> <p class="field switch">  <?php $status = $rows['status']; ?> <input type="radio" name="selstatus" value="no" <?php if($status == 'yes') {echo 'checked';} else {echo '';} ?>/> <input type="radio" name="selstatus" value="yes" <?php if($status == 'yes') {echo 'checked';} else {echo '';} ?>/> <input type="hidden" name="statusid" value="<?php echo $rows['id']; ?>"/> <label for="radio1" class="cb-enable <?php if($status == 'yes') {echo 'selected';} else {echo '';} ?>"><span>Yes</span></label> <label for="radio2" class="cb-disable <?php if($status == 'no') {echo 'selected';} else {echo '';} ?>"><span>No</span></label> </p> </div></td> </tr> <tr> <td></td> <?php } } ?> <td align="center"><div style="padding-left: 30px;"> <button type="submit">Update</button> <input type="hidden" name="notc2" value="1"/> </div></td> </tr> </table> </form> </div> </body> processing <?php // 6) update notifications if (array_key_exists('notc2',$_POST)) { echo "<p style='font-size: 12px;'>Thank you. The notifications have been updated successfully.<p>"; echo "<p><span style='font-size: 12px;'> <a onClick=\"history.go(-1)\" class='form'>Return</a></p> <p></span> "; exit; }; ?> after doing some research i learnt that the only way to insert multiple radio values into the MYSQL table is to use arrays. there was a similar question raised somewhere on this site: http://stackoverflow.com/questions/1656260/php-multiple-radio-buttons that recommended using a foreach loop. use a foreach loop <?php foreach ( $_POST as $key => $val ) echo "$key -> $val\n"; ?> $key will be the name of the selected option and $val, well, the value. how would this apply to my situation as i am struggling to find any help on the internet. i understand that i would use this on the processing page to pull out any radio values from the previous page and then loop the INSERT MYSQL code within the process until it was all done. any advice would be appreciated! GOD BLESS.

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Assignment operator that calls a constructor is broken

- by Delan Azabani

I've implemented some of the changes suggested in this question, and (thanks very much) it works quite well, however... in the process I've seemed to break the post-declaration assignment operator. With the following code: #include <cstdio> #include "ucpp" main() { ustring a = "test"; ustring b = "ing"; ustring c = "- -"; ustring d = "cafe\xcc\x81"; printf("%s\n", (a + b + c[1] + d).encode()); } I get a nice "testing cafe´" message. However, if I modify the code slightly so that the const char * conversion is done separately, post-declaration: #include <cstdio> #include "ucpp" main() { ustring a = "test"; ustring b = "ing"; ustring c = "- -"; ustring d; d = "cafe\xcc\x81"; printf("%s\n", (a + b + c[1] + d).encode()); } the ustring named d becomes blank, and all that is output is "testing ". My new code has three constructors, one void (which is probably the one being incorrectly used, and is used in the operator+ function), one that takes a const ustring &, and one that takes a const char *. The following is my new library code: #include <cstdlib> #include <cstring> class ustring { int * values; long len; public: long length() { return len; } ustring() { len = 0; values = (int *) malloc(0); } ustring(const ustring &input) { len = input.len; values = (int *) malloc(sizeof(int) * len); for (long i = 0; i < len; i++) values[i] = input.values[i]; } ustring operator=(ustring input) { ustring result(input); return result; } ustring(const char * input) { values = (int *) malloc(0); long s = 0; // s = number of parsed chars int a, b, c, d, contNeed = 0, cont = 0; for (long i = 0; input[i]; i++) if (input[i] < 0x80) { // ASCII, direct copy (00-7f) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = input[i]; } else if (input[i] < 0xc0) { // this is a continuation (80-bf) if (cont == contNeed) { // no need for continuation, use U+fffd values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } cont = cont + 1; values[s - 1] = values[s - 1] | ((input[i] & 0x3f) << ((contNeed - cont) * 6)); if (cont == contNeed) cont = contNeed = 0; } else if (input[i] < 0xc2) { // invalid byte, use U+fffd (c0-c1) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } else if (input[i] < 0xe0) { // start of 2-byte sequence (c2-df) contNeed = 1; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x1f) << 6; } else if (input[i] < 0xf0) { // start of 3-byte sequence (e0-ef) contNeed = 2; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x0f) << 12; } else if (input[i] < 0xf5) { // start of 4-byte sequence (f0-f4) contNeed = 3; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x07) << 18; } else { // restricted or invalid (f5-ff) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } len = s; } ustring operator=(const char * input) { ustring result(input); return result; } ustring operator+(ustring input) { ustring result; result.len = len + input.len; result.values = (int *) malloc(sizeof(int) * result.len); for (long i = 0; i < len; i++) result.values[i] = values[i]; for (long i = 0; i < input.len; i++) result.values[i + len] = input.values[i]; return result; } ustring operator[](long index) { ustring result; result.len = 1; result.values = (int *) malloc(sizeof(int)); result.values[0] = values[index]; return result; } char * encode() { char * r = (char *) malloc(0); long s = 0; for (long i = 0; i < len; i++) { if (values[i] < 0x80) r = (char *) realloc(r, s + 1), r[s + 0] = char(values[i]), s += 1; else if (values[i] < 0x800) r = (char *) realloc(r, s + 2), r[s + 0] = char(values[i] >> 6 | 0x60), r[s + 1] = char(values[i] & 0x3f | 0x80), s += 2; else if (values[i] < 0x10000) r = (char *) realloc(r, s + 3), r[s + 0] = char(values[i] >> 12 | 0xe0), r[s + 1] = char(values[i] >> 6 & 0x3f | 0x80), r[s + 2] = char(values[i] & 0x3f | 0x80), s += 3; else r = (char *) realloc(r, s + 4), r[s + 0] = char(values[i] >> 18 | 0xf0), r[s + 1] = char(values[i] >> 12 & 0x3f | 0x80), r[s + 2] = char(values[i] >> 6 & 0x3f | 0x80), r[s + 3] = char(values[i] & 0x3f | 0x80), s += 4; } return r; } };

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Flash and Google Maps - Only Last Icon showing

- by Peter

I have a simple Map and geocoding sample in Flash using CS4 The problem is simple - I can retrieve a short list from the google search api, but when I try to generate the icons on the map using a loop, only the last icon is displayed. (ignore the house icon, it is generated earlier) I feel I am missing something or made a stupid AS3 mistake (like treating it as if it was c#) - or even a stupid wood-for-the-trees mistake. The problem is in the last line of the code. I have added all my code just in case somebody else can find a use for it - lord knows it took me a great while to figure this out :) It runs here (also, if anybody has an idea why the icon is slightly in the wrong place on render, but corrects if you move the map - please let me know) Any help would be great. Thanks. P import com.google.maps.services.ClientGeocoder; import com.google.maps.services.GeocodingEvent; import com.google.maps.LatLng; import com.google.maps.Map; import com.google.maps.MapEvent; import com.google.maps.MapType; import com.google.maps.overlays.Marker; import com.google.maps.overlays.MarkerOptions; import com.google.maps.styles.FillStyle; import com.google.maps.styles.StrokeStyle; import com.google.maps.controls.* import com.google.maps.overlays.* import flash.display.Bitmap; import flash.display.BitmapData; import com.adobe.utils.StringUtil; import be.boulevart.google.ajaxapi.search.GoogleSearchResult; import be.boulevart.google.events.GoogleApiEvent; import be.boulevart.google.ajaxapi.search.local.GoogleLocalSearch; import be.boulevart.google.ajaxapi.search.local.data.GoogleLocalSearchItem; var strZip:String = new String(); strZip="60661"; var strAddress:String = new String(); strAddress ="100 W. Jackson Blvd, chicago, IL 60661"; var IconArray:Array = new Array; var SearchArray:Array = new Array; /*-------------------------------------------------------------- // The returned search data gets placed into this array ---------------------------------------------------------------*/ var LocalInfo:Array = new Array(); var intCount:int = new int; var intMapReady:int=0; /*=================================================================================== We load the map first and then get the search criteria - this will keep the order of operation clean. The ====================================================================================*/ var map:Map = new Map(); map.key = "ABQIAAAAHwSPp7Lhew456ffD6qa2WmxT_VwdLJEfmcCgytxKjcH1jLKkiihQtfC- TbcwryvBQYhRwHWa8F_Gp9Q"; map.setSize(new Point(600, 550)); map.addEventListener(MapEvent.MAP_READY, onMapReady); //Places the map on the page this.addChild(map); map.x=5; map.y=5; function onMapReady(event:Event):void { //Center the map and place the house marker doGeocode(); } /*========================================================================== Goecode to return the LAT and LONG for the specific address, center the map and add the house icon ===========================================================================*/ function doGeocode() { var geocoder:ClientGeocoder = new ClientGeocoder(); geocoder.addEventListener(GeocodingEvent.GEOCODING_SUCCESS, function(event:GeocodingEvent):void { var objPlacemarks:Array = event.response.placemarks; if (objPlacemarks.length > 0) { map.setCenter(objPlacemarks[0].point, 14, MapType.NORMAL_MAP_TYPE); var request:URLRequest = new URLRequest("house.png"); var imageLoader:Loader = new Loader(); imageLoader.load(request); var objMarkerOptions:MarkerOptions = new MarkerOptions(); objMarkerOptions.icon=imageLoader; objMarkerOptions.icon.scaleX=.15; objMarkerOptions.icon.scaleY=.15; objMarkerOptions.iconAlignment = MarkerOptions.ALIGN_HORIZONTAL_CENTER + MarkerOptions.ALIGN_VERTICAL_CENTER; var objMarker:Marker = new Marker(objPlacemarks[0].point, objMarkerOptions); map.addOverlay(objMarker); doLoadSearch() } }); //Failure code - good practice, really geocoder.addEventListener(GeocodingEvent.GEOCODING_FAILURE, function(event:GeocodingEvent):void { txtResult.appendText("Geocoding failed"); }); // generate geocode geocoder.geocode(strAddress); } /*=============================================================== XML Loader - loads icon file and search text pair from xml file =================================================================*/ function doLoadSearch() { var xmlLoader:URLLoader = new URLLoader(); var xmlData:XML = new XML(); xmlLoader.addEventListener(Event.COMPLETE, LoadXML); xmlLoader.load(new URLRequest("config.xml")); function LoadXML(e:Event):void { xmlData = new XML(e.target.data); RetrieveSearch(); } function RetrieveSearch() { //extract the MapData subset var xmlSearch = xmlData.MapData; // push this to an xml list object var xmlChildren:XMLList = xmlSearch.children(); //loop the list and extract the data into an //array of formatted search criteria for each (var Search:XML in xmlChildren) { txtResult.appendText("Searching For: "+Search.Criteria+" Icon=" + Search.Icon+ "Zip=" + strZip +"\r\n\r\n"); //retrieve search criteria loadLocalInfo(Search.Criteria,Search.Icon,strZip); } } } /*================================================================================== Search Functionality - does a google API search and loads the lats and longs required to place the icons on the map - THIS WILL NOT RUN LOCALLY ===================================================================================*/ function loadLocalInfo(strSearch,strIcon,strZip) { var objLocal:GoogleLocalSearch=new GoogleLocalSearch() objLocal.search(strSearch+" "+strZip,0,"0,0","","") objLocal.addEventListener(GoogleApiEvent.LOCAL_SEARCH_RESULT,onSearchComplete) function onSearchComplete(e:GoogleApiEvent):void { var resulta:GoogleSearchResult=e.data as GoogleSearchResult; //------------------------------------------------ // Load the icon for this particular search //------------------------------------------------ var request:URLRequest = new URLRequest(strIcon); var imageLoader:Loader = new Loader(); imageLoader.load(request); //------------------------------------------------------------- // For test purposes txtResult.appendText("Result Count for "+strSearch+" = "+e.data.results.length+"\r\n\r\n"); for each (var result:GoogleLocalSearchItem in e.data.results as Array) { LocalInfo[intCount]=[String(result.title),strIcon,String(result.latitude),String(result.longitude)]; //--------------------------------------- // Pop the icon onto the map //--------------------------------------- var objLatLng:LatLng = new LatLng(parseFloat(result.latitude), parseFloat(result.longitude)); var objMarkerOptions:MarkerOptions = new MarkerOptions(); objMarkerOptions.icon=imageLoader; objMarkerOptions.hasShadow=false; objMarkerOptions.iconAlignment = MarkerOptions.ALIGN_HORIZONTAL_CENTER + MarkerOptions.ALIGN_VERTICAL_CENTER; var objMarker:Marker = new Marker(objLatLng, objMarkerOptions); /********************************************************** *Everything* works to here - I have traced out execution and all variables. It only works on the last item in the array :( ***********************************************************/ map.addOverlay(objMarker); } } }

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F# - Facebook Hacker Cup - Double Squares

- by Jacob

I'm working on strengthening my F#-fu and decided to tackle the Facebook Hacker Cup Double Squares problem. I'm having some problems with the run-time and was wondering if anyone could help me figure out why it is so much slower than my C# equivalent. There's a good description from another post; Source: Facebook Hacker Cup Qualification Round 2011 A double-square number is an integer X which can be expressed as the sum of two perfect squares. For example, 10 is a double-square because 10 = 3^2 + 1^2. Given X, how can we determine the number of ways in which it can be written as the sum of two squares? For example, 10 can only be written as 3^2 + 1^2 (we don't count 1^2 + 3^2 as being different). On the other hand, 25 can be written as 5^2 + 0^2 or as 4^2 + 3^2. You need to solve this problem for 0 = X = 2,147,483,647. Examples: 10 = 1 25 = 2 3 = 0 0 = 1 1 = 1 My basic strategy (which I'm open to critique on) is to; Create a dictionary (for memoize) of the input numbers initialzed to 0 Get the largest number (LN) and pass it to count/memo function Get the LN square root as int Calculate squares for all numbers 0 to LN and store in dict Sum squares for non repeat combinations of numbers from 0 to LN If sum is in memo dict, add 1 to memo Finally, output the counts of the original numbers. Here is the F# code (See code changes at bottom) I've written that I believe corresponds to this strategy (Runtime: ~8:10); open System open System.Collections.Generic open System.IO /// Get a sequence of values let rec range min max = seq { for num in [min .. max] do yield num } /// Get a sequence starting from 0 and going to max let rec zeroRange max = range 0 max /// Find the maximum number in a list with a starting accumulator (acc) let rec maxNum acc = function | [] -> acc | p::tail when p > acc -> maxNum p tail | p::tail -> maxNum acc tail /// A helper for finding max that sets the accumulator to 0 let rec findMax nums = maxNum 0 nums /// Build a collection of combinations; ie [1,2,3] = (1,1), (1,2), (1,3), (2,2), (2,3), (3,3) let rec combos range = seq { let count = ref 0 for inner in range do for outer in Seq.skip !count range do yield (inner, outer) count := !count + 1 } let rec squares nums = let dict = new Dictionary<int, int>() for s in nums do dict.[s] <- (s * s) dict /// Counts the number of possible double squares for a given number and keeps track of other counts that are provided in the memo dict. let rec countDoubleSquares (num: int) (memo: Dictionary<int, int>) = // The highest relevent square is the square root because it squared plus 0 squared is the top most possibility let maxSquare = System.Math.Sqrt((float)num) // Our relevant squares are 0 to the highest possible square; note the cast to int which shouldn't hurt. let relSquares = range 0 ((int)maxSquare) // calculate the squares up front; let calcSquares = squares relSquares // Build up our square combinations; ie [1,2,3] = (1,1), (1,2), (1,3), (2,2), (2,3), (3,3) for (sq1, sq2) in combos relSquares do let v = calcSquares.[sq1] + calcSquares.[sq2] // Memoize our relevant results if memo.ContainsKey(v) then memo.[v] <- memo.[v] + 1 // return our count for the num passed in memo.[num] // Read our numbers from file. //let lines = File.ReadAllLines("test2.txt") //let nums = [ for line in Seq.skip 1 lines -> Int32.Parse(line) ] // Optionally, read them from straight array let nums = [1740798996; 1257431873; 2147483643; 602519112; 858320077; 1048039120; 415485223; 874566596; 1022907856; 65; 421330820; 1041493518; 5; 1328649093; 1941554117; 4225; 2082925; 0; 1; 3] // Initialize our memoize dictionary let memo = new Dictionary<int, int>() for num in nums do memo.[num] <- 0 // Get the largest number in our set, all other numbers will be memoized along the way let maxN = findMax nums // Do the memoize let maxCount = countDoubleSquares maxN memo // Output our results. for num in nums do printfn "%i" memo.[num] // Have a little pause for when we debug let line = Console.Read() And here is my version in C# (Runtime: ~1:40: using System; using System.Collections.Generic; using System.Diagnostics; using System.IO; using System.Linq; using System.Text; namespace FBHack_DoubleSquares { public class TestInput { public int NumCases { get; set; } public List<int> Nums { get; set; } public TestInput() { Nums = new List<int>(); } public int MaxNum() { return Nums.Max(); } } class Program { static void Main(string[] args) { // Read input from file. //TestInput input = ReadTestInput("live.txt"); // As example, load straight. TestInput input = new TestInput { NumCases = 20, Nums = new List<int> { 1740798996, 1257431873, 2147483643, 602519112, 858320077, 1048039120, 415485223, 874566596, 1022907856, 65, 421330820, 1041493518, 5, 1328649093, 1941554117, 4225, 2082925, 0, 1, 3, } }; var maxNum = input.MaxNum(); Dictionary<int, int> memo = new Dictionary<int, int>(); foreach (var num in input.Nums) { if (!memo.ContainsKey(num)) memo.Add(num, 0); } DoMemoize(maxNum, memo); StringBuilder sb = new StringBuilder(); foreach (var num in input.Nums) { //Console.WriteLine(memo[num]); sb.AppendLine(memo[num].ToString()); } Console.Write(sb.ToString()); var blah = Console.Read(); //File.WriteAllText("out.txt", sb.ToString()); } private static int DoMemoize(int num, Dictionary<int, int> memo) { var highSquare = (int)Math.Floor(Math.Sqrt(num)); var squares = CreateSquareLookup(highSquare); var relSquares = squares.Keys.ToList(); Debug.WriteLine("Starting - " + num.ToString()); Debug.WriteLine("RelSquares.Count = {0}", relSquares.Count); int sum = 0; var index = 0; foreach (var square in relSquares) { foreach (var inner in relSquares.Skip(index)) { sum = squares[square] + squares[inner]; if (memo.ContainsKey(sum)) memo[sum]++; } index++; } if (memo.ContainsKey(num)) return memo[num]; return 0; } private static TestInput ReadTestInput(string fileName) { var lines = File.ReadAllLines(fileName); var input = new TestInput(); input.NumCases = int.Parse(lines[0]); foreach (var lin in lines.Skip(1)) { input.Nums.Add(int.Parse(lin)); } return input; } public static Dictionary<int, int> CreateSquareLookup(int maxNum) { var dict = new Dictionary<int, int>(); int square; foreach (var num in Enumerable.Range(0, maxNum)) { square = num * num; dict[num] = square; } return dict; } } } Thanks for taking a look. UPDATE Changing the combos function slightly will result in a pretty big performance boost (from 8 min to 3:45): /// Old and Busted... let rec combosOld range = seq { let rangeCache = Seq.cache range let count = ref 0 for inner in rangeCache do for outer in Seq.skip !count rangeCache do yield (inner, outer) count := !count + 1 } /// The New Hotness... let rec combos maxNum = seq { for i in 0..maxNum do for j in i..maxNum do yield i,j }

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Capturing and Transforming ASP.NET Output with Response.Filter

- by Rick Strahl

During one of my Handlers and Modules session at DevConnections this week one of the attendees asked a question that I didn’t have an immediate answer for. Basically he wanted to capture response output completely and then apply some filtering to the output – effectively injecting some additional content into the page AFTER the page had completely rendered. Specifically the output should be captured from anywhere – not just a page and have this code injected into the page. Some time ago I posted some code that allows you to capture ASP.NET Page output by overriding the Render() method, capturing the HtmlTextWriter() and reading its content, modifying the rendered data as text then writing it back out. I’ve actually used this approach on a few occasions and it works fine for ASP.NET pages. But this obviously won’t work outside of the Page class environment and it’s not really generic – you have to create a custom page class in order to handle the output capture. [updated 11/16/2009 – updated ResponseFilterStream implementation and a few additional notes based on comments] Enter Response.Filter However, ASP.NET includes a Response.Filter which can be used – well to filter output. Basically Response.Filter is a stream through which the OutputStream is piped back to the Web Server (indirectly). As content is written into the Response object, the filter stream receives the appropriate Stream commands like Write, Flush and Close as well as read operations although for a Response.Filter that’s uncommon to be hit. The Response.Filter can be programmatically replaced at runtime which allows you to effectively intercept all output generation that runs through ASP.NET. A common Example: Dynamic GZip Encoding A rather common use of Response.Filter hooking up code based, dynamic GZip compression for requests which is dead simple by applying a GZipStream (or DeflateStream) to Response.Filter. The following generic routines can be used very easily to detect GZip capability of the client and compress response output with a single line of code and a couple of library helper routines: WebUtils.GZipEncodePage(); which is handled with a few lines of reusable code and a couple of static helper methods: /// <summary> ///Sets up the current page or handler to use GZip through a Response.Filter ///IMPORTANT: ///You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() { HttpResponse Response = HttpContext.Current.Response; if(IsGZipSupported()) { stringAcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if(AcceptEncoding.Contains("deflate")) { Response.Filter = newSystem.IO.Compression.DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.AppendHeader("Content-Encoding", "deflate"); } else { Response.Filter = newSystem.IO.Compression.GZipStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.AppendHeader("Content-Encoding", "gzip"); } } // Allow proxy servers to cache encoded and unencoded versions separately Response.AppendHeader("Vary", "Content-Encoding"); } /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } GZipStream and DeflateStream are streams that are assigned to Response.Filter and by doing so apply the appropriate compression on the active Response. Response.Filter content is chunked So to implement a Response.Filter effectively requires only that you implement a custom stream and handle the Write() method to capture Response output as it’s written. At first blush this seems very simple – you capture the output in Write, transform it and write out the transformed content in one pass. And that indeed works for small amounts of content. But you see, the problem is that output is written in small buffer chunks (a little less than 16k it appears) rather than just a single Write() statement into the stream, which makes perfect sense for ASP.NET to stream data back to IIS in smaller chunks to minimize memory usage en route. Unfortunately this also makes it a more difficult to implement any filtering routines since you don’t directly get access to all of the response content which is problematic especially if those filtering routines require you to look at the ENTIRE response in order to transform or capture the output as is needed for the solution the gentleman in my session asked for. So in order to address this a slightly different approach is required that basically captures all the Write() buffers passed into a cached stream and then making the stream available only when it’s complete and ready to be flushed. As I was thinking about the implementation I also started thinking about the few instances when I’ve used Response.Filter implementations. Each time I had to create a new Stream subclass and create my custom functionality but in the end each implementation did the same thing – capturing output and transforming it. I thought there should be an easier way to do this by creating a re-usable Stream class that can handle stream transformations that are common to Response.Filter implementations. Creating a semi-generic Response Filter Stream Class What I ended up with is a ResponseFilterStream class that provides a handful of Events that allow you to capture and/or transform Response content. The class implements a subclass of Stream and then overrides Write() and Flush() to handle capturing and transformation operations. By exposing events it’s easy to hook up capture or transformation operations via single focused methods. ResponseFilterStream exposes the following events: CaptureStream, CaptureString Captures the output only and provides either a MemoryStream or String with the final page output. Capture is hooked to the Flush() operation of the stream. TransformStream, TransformString Allows you to transform the complete response output with events that receive a MemoryStream or String respectively and can you modify the output then return it back as a return value. The transformed output is then written back out in a single chunk to the response output stream. These events capture all output internally first then write the entire buffer into the response. TransformWrite, TransformWriteString Allows you to transform the Response data as it is written in its original chunk size in the Stream’s Write() method. Unlike TransformStream/TransformString which operate on the complete output, these events only see the current chunk of data written. This is more efficient as there’s no caching involved, but can cause problems due to searched content splitting over multiple chunks. Using this implementation, creating a custom Response.Filter transformation becomes as simple as the following code. To hook up the Response.Filter using the MemoryStream version event: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformStream += filter_TransformStream; Response.Filter = filter; and the event handler to do the transformation: MemoryStream filter_TransformStream(MemoryStream ms) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = encoding.GetString(ms.ToArray()); output = FixPaths(output); ms = new MemoryStream(output.Length); byte[] buffer = encoding.GetBytes(output); ms.Write(buffer,0,buffer.Length); return ms; } private string FixPaths(string output) { string path = HttpContext.Current.Request.ApplicationPath; // override root path wonkiness if (path == "/") path = ""; output = output.Replace("\"~/", "\"" + path + "/").Replace("'~/", "'" + path + "/"); return output; } The idea of the event handler is that you can do whatever you want to the stream and return back a stream – either the same one that’s been modified or a brand new one – which is then sent back to as the final response. The above code can be simplified even more by using the string version events which handle the stream to string conversions for you: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; and the event handler to do the transformation calling the same FixPaths method shown above: string filter_TransformString(string output) { return FixPaths(output); } The events for capturing output and capturing and transforming chunks work in a very similar way. By using events to handle the transformations ResponseFilterStream becomes a reusable component and we don’t have to create a new stream class or subclass an existing Stream based classed. By the way, the example used here is kind of a cool trick which transforms “~/” expressions inside of the final generated HTML output – even in plain HTML controls not HTML controls – and transforms them into the appropriate application relative path in the same way that ResolveUrl would do. So you can write plain old HTML like this: <a href=”~/default.aspx”>Home</a> and have it turned into: <a href=”/myVirtual/default.aspx”>Home</a> without having to use an ASP.NET control like Hyperlink or Image or having to constantly use: <img src=”<%= ResolveUrl(“~/images/home.gif”) %>” /> in MVC applications (which frankly is one of the most annoying things about MVC especially given the path hell that extension-less and endpoint-less URLs impose). I can’t take credit for this idea. While discussing the Response.Filter issues on Twitter a hint from Dylan Beattie who pointed me at one of his examples which does something similar. I thought the idea was cool enough to use an example for future demos of Response.Filter functionality in ASP.NET next I time I do the Modules and Handlers talk (which was great fun BTW). How practical this is is debatable however since there’s definitely some overhead to using a Response.Filter in general and especially on one that caches the output and the re-writes it later. Make sure to test for performance anytime you use Response.Filter hookup and make sure it' doesn’t end up killing perf on you. You’ve been warned :-}. How does ResponseFilterStream work? The big win of this implementation IMHO is that it’s a reusable component – so for implementation there’s no new class, no subclassing – you simply attach to an event to implement an event handler method with a straight forward signature to retrieve the stream or string you’re interested in. The implementation is based on a subclass of Stream as is required in order to handle the Response.Filter requirements. What’s different than other implementations I’ve seen in various places is that it supports capturing output as a whole to allow retrieving the full response output for capture or modification. The exception are the TransformWrite and TransformWrite events which operate only active chunk of data written by the Response. For captured output, the Write() method captures output into an internal MemoryStream that is cached until writing is complete. So Write() is called when ASP.NET writes to the Response stream, but the filter doesn’t pass on the Write immediately to the filter’s internal stream. The data is cached and only when the Flush() method is called to finalize the Stream’s output do we actually send the cached stream off for transformation (if the events are hooked up) and THEN finally write out the returned content in one big chunk. Here’s the implementation of ResponseFilterStream: /// <summary> /// A semi-generic Stream implementation for Response.Filter with /// an event interface for handling Content transformations via /// Stream or String. /// <remarks> /// Use with care for large output as this implementation copies /// the output into a memory stream and so increases memory usage. /// </remarks> /// </summary> public class ResponseFilterStream : Stream { /// <summary> /// The original stream /// </summary> Stream _stream; /// <summary> /// Current position in the original stream /// </summary> long _position; /// <summary> /// Stream that original content is read into /// and then passed to TransformStream function /// </summary> MemoryStream _cacheStream = new MemoryStream(5000); /// <summary> /// Internal pointer that that keeps track of the size /// of the cacheStream /// </summary> int _cachePointer = 0; /// <summary> /// /// </summary> /// <param name="responseStream"></param> public ResponseFilterStream(Stream responseStream) { _stream = responseStream; } /// <summary> /// Determines whether the stream is captured /// </summary> private bool IsCaptured { get { if (CaptureStream != null || CaptureString != null || TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Determines whether the Write method is outputting data immediately /// or delaying output until Flush() is fired. /// </summary> private bool IsOutputDelayed { get { if (TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Event that captures Response output and makes it available /// as a MemoryStream instance. Output is captured but won't /// affect Response output. /// </summary> public event Action<MemoryStream> CaptureStream; /// <summary> /// Event that captures Response output and makes it available /// as a string. Output is captured but won't affect Response output. /// </summary> public event Action<string> CaptureString; /// <summary> /// Event that allows you transform the stream as each chunk of /// the output is written in the Write() operation of the stream. /// This means that that it's possible/likely that the input /// buffer will not contain the full response output but only /// one of potentially many chunks. /// /// This event is called as part of the filter stream's Write() /// operation. /// </summary> public event Func<byte[], byte[]> TransformWrite; /// <summary> /// Event that allows you to transform the response stream as /// each chunk of bytep[] output is written during the stream's write /// operation. This means it's possibly/likely that the string /// passed to the handler only contains a portion of the full /// output. Typical buffer chunks are around 16k a piece. /// /// This event is called as part of the stream's Write operation. /// </summary> public event Func<string, string> TransformWriteString; /// <summary> /// This event allows capturing and transformation of the entire /// output stream by caching all write operations and delaying final /// response output until Flush() is called on the stream. /// </summary> public event Func<MemoryStream, MemoryStream> TransformStream; /// <summary> /// Event that can be hooked up to handle Response.Filter /// Transformation. Passed a string that you can modify and /// return back as a return value. The modified content /// will become the final output. /// </summary> public event Func<string, string> TransformString; protected virtual void OnCaptureStream(MemoryStream ms) { if (CaptureStream != null) CaptureStream(ms); } private void OnCaptureStringInternal(MemoryStream ms) { if (CaptureString != null) { string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); OnCaptureString(content); } } protected virtual void OnCaptureString(string output) { if (CaptureString != null) CaptureString(output); } protected virtual byte[] OnTransformWrite(byte[] buffer) { if (TransformWrite != null) return TransformWrite(buffer); return buffer; } private byte[] OnTransformWriteStringInternal(byte[] buffer) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = OnTransformWriteString(encoding.GetString(buffer)); return encoding.GetBytes(output); } private string OnTransformWriteString(string value) { if (TransformWriteString != null) return TransformWriteString(value); return value; } protected virtual MemoryStream OnTransformCompleteStream(MemoryStream ms) { if (TransformStream != null) return TransformStream(ms); return ms; } /// <summary> /// Allows transforming of strings /// /// Note this handler is internal and not meant to be overridden /// as the TransformString Event has to be hooked up in order /// for this handler to even fire to avoid the overhead of string /// conversion on every pass through. /// </summary> /// <param name="responseText"></param> /// <returns></returns> private string OnTransformCompleteString(string responseText) { if (TransformString != null) TransformString(responseText); return responseText; } /// <summary> /// Wrapper method form OnTransformString that handles /// stream to string and vice versa conversions /// </summary> /// <param name="ms"></param> /// <returns></returns> internal MemoryStream OnTransformCompleteStringInternal(MemoryStream ms) { if (TransformString == null) return ms; //string content = ms.GetAsString(); string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); content = TransformString(content); byte[] buffer = HttpContext.Current.Response.ContentEncoding.GetBytes(content); ms = new MemoryStream(); ms.Write(buffer, 0, buffer.Length); //ms.WriteString(content); return ms; } /// <summary> /// /// </summary> public override bool CanRead { get { return true; } } public override bool CanSeek { get { return true; } } /// <summary> /// /// </summary> public override bool CanWrite { get { return true; } } /// <summary> /// /// </summary> public override long Length { get { return 0; } } /// <summary> /// /// </summary> public override long Position { get { return _position; } set { _position = value; } } /// <summary> /// /// </summary> /// <param name="offset"></param> /// <param name="direction"></param> /// <returns></returns> public override long Seek(long offset, System.IO.SeekOrigin direction) { return _stream.Seek(offset, direction); } /// <summary> /// /// </summary> /// <param name="length"></param> public override void SetLength(long length) { _stream.SetLength(length); } /// <summary> /// /// </summary> public override void Close() { _stream.Close(); } /// <summary> /// Override flush by writing out the cached stream data /// </summary> public override void Flush() { if (IsCaptured && _cacheStream.Length > 0) { // Check for transform implementations _cacheStream = OnTransformCompleteStream(_cacheStream); _cacheStream = OnTransformCompleteStringInternal(_cacheStream); OnCaptureStream(_cacheStream); OnCaptureStringInternal(_cacheStream); // write the stream back out if output was delayed if (IsOutputDelayed) _stream.Write(_cacheStream.ToArray(), 0, (int)_cacheStream.Length); // Clear the cache once we've written it out _cacheStream.SetLength(0); } // default flush behavior _stream.Flush(); } /// <summary> /// /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> /// <returns></returns> public override int Read(byte[] buffer, int offset, int count) { return _stream.Read(buffer, offset, count); } /// <summary> /// Overriden to capture output written by ASP.NET and captured /// into a cached stream that is written out later when Flush() /// is called. /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> public override void Write(byte[] buffer, int offset, int count) { if ( IsCaptured ) { // copy to holding buffer only - we'll write out later _cacheStream.Write(buffer, 0, count); _cachePointer += count; } // just transform this buffer if (TransformWrite != null) buffer = OnTransformWrite(buffer); if (TransformWriteString != null) buffer = OnTransformWriteStringInternal(buffer); if (!IsOutputDelayed) _stream.Write(buffer, offset, buffer.Length); } } The key features are the events and corresponding OnXXX methods that handle the event hookups, and the Write() and Flush() methods of the stream implementation. All the rest of the members tend to be plain jane passthrough stream implementation code without much consequence. I do love the way Action<t> and Func<T> make it so easy to create the event signatures for the various events – sweet. A few Things to consider Performance Response.Filter is not great for performance in general as it adds another layer of indirection to the ASP.NET output pipeline, and this implementation in particular adds a memory hit as it basically duplicates the response output into the cached memory stream which is necessary since you may have to look at the entire response. If you have large pages in particular this can cause potentially serious memory pressure in your server application. So be careful of wholesale adoption of this (or other) Response.Filters. Make sure to do some performance testing to ensure it’s not killing your app’s performance. Response.Filter works everywhere A few questions came up in comments and discussion as to capturing ALL output hitting the site and – yes you can definitely do that by assigning a Response.Filter inside of a module. If you do this however you’ll want to be very careful and decide which content you actually want to capture especially in IIS 7 which passes ALL content – including static images/CSS etc. through the ASP.NET pipeline. So it is important to filter only on what you’re looking for – like the page extension or maybe more effectively the Response.ContentType. Response.Filter Chaining Originally I thought that filter chaining doesn’t work at all due to a bug in the stream implementation code. But it’s quite possible to assign multiple filters to the Response.Filter property. So the following actually works to both compress the output and apply the transformed content: WebUtils.GZipEncodePage(); ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; However the following does not work resulting in invalid content encoding errors: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; WebUtils.GZipEncodePage(); In other words multiple Response filters can work together but it depends entirely on the implementation whether they can be chained or in which order they can be chained. In this case running the GZip/Deflate stream filters apparently relies on the original content length of the output and chokes when the content is modified. But if attaching the compression first it works fine as unintuitive as that may seem. Resources Download example code Capture Output from ASP.NET Pages © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET

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Custom ASP.NET Routing to an HttpHandler

- by Rick Strahl

As of version 4.0 ASP.NET natively supports routing via the now built-in System.Web.Routing namespace. Routing features are automatically integrated into the HtttpRuntime via a few custom interfaces. New Web Forms Routing Support In ASP.NET 4.0 there are a host of improvements including routing support baked into Web Forms via a RouteData property available on the Page class and RouteCollection.MapPageRoute() route handler that makes it easy to route to Web forms. To map ASP.NET Page routes is as simple as setting up the routes with MapPageRoute:protected void Application_Start(object sender, EventArgs e) { RegisterRoutes(RouteTable.Routes); } void RegisterRoutes(RouteCollection routes) { routes.MapPageRoute("StockQuote", "StockQuote/{symbol}", "StockQuote.aspx"); routes.MapPageRoute("StockQuotes", "StockQuotes/{symbolList}", "StockQuotes.aspx"); } and then accessing the route data in the page you can then use the new Page class RouteData property to retrieve the dynamic route data information:public partial class StockQuote1 : System.Web.UI.Page { protected StockQuote Quote = null; protected void Page_Load(object sender, EventArgs e) { string symbol = RouteData.Values["symbol"] as string; StockServer server = new StockServer(); Quote = server.GetStockQuote(symbol); // display stock data in Page View } } Simple, quick and doesn’t require much explanation. If you’re using WebForms most of your routing needs should be served just fine by this simple mechanism. Kudos to the ASP.NET team for putting this in the box and making it easy! How Routing Works To handle Routing in ASP.NET involves these steps: Registering Routes Creating a custom RouteHandler to retrieve an HttpHandler Attaching RouteData to your HttpHandler Picking up Route Information in your Request code Registering routes makes ASP.NET aware of the Routes you want to handle via the static RouteTable.Routes collection. You basically add routes to this collection to let ASP.NET know which URL patterns it should watch for. You typically hook up routes off a RegisterRoutes method that fires in Application_Start as I did in the example above to ensure routes are added only once when the application first starts up. When you create a route, you pass in a RouteHandler instance which ASP.NET caches and reuses as routes are matched. Once registered ASP.NET monitors the routes and if a match is found just prior to the HttpHandler instantiation, ASP.NET uses the RouteHandler registered for the route and calls GetHandler() on it to retrieve an HttpHandler instance. The RouteHandler.GetHandler() method is responsible for creating an instance of an HttpHandler that is to handle the request and – if necessary – to assign any additional custom data to the handler. At minimum you probably want to pass the RouteData to the handler so the handler can identify the request based on the route data available. To do this you typically add a RouteData property to your handler and then assign the property from the RouteHandlers request context. This is essentially how Page.RouteData comes into being and this approach should work well for any custom handler implementation that requires RouteData. It’s a shame that ASP.NET doesn’t have a top level intrinsic object that’s accessible off the HttpContext object to provide route data more generically, but since RouteData is directly tied to HttpHandlers and not all handlers support it it might cause some confusion of when it’s actually available. Bottom line is that if you want to hold on to RouteData you have to assign it to a custom property of the handler or else pass it to the handler via Context.Items[] object that can be retrieved on an as needed basis. It’s important to understand that routing is hooked up via RouteHandlers that are responsible for loading HttpHandler instances. RouteHandlers are invoked for every request that matches a route and through this RouteHandler instance the Handler gains access to the current RouteData. Because of this logic it’s important to understand that Routing is really tied to HttpHandlers and not available prior to handler instantiation, which is pretty late in the HttpRuntime’s request pipeline. IOW, Routing works with Handlers but not with earlier in the pipeline within Modules. Specifically ASP.NET calls RouteHandler.GetHandler() from the PostResolveRequestCache HttpRuntime pipeline event. Here’s the call stack at the beginning of the GetHandler() call: which fires just before handler resolution. Non-Page Routing – You need to build custom RouteHandlers If you need to route to a custom Http Handler or other non-Page (and non-MVC) endpoint in the HttpRuntime, there is no generic mapping support available. You need to create a custom RouteHandler that can manage creating an instance of an HttpHandler that is fired in response to a routed request. Depending on what you are doing this process can be simple or fairly involved as your code is responsible based on the route data provided which handler to instantiate, and more importantly how to pass the route data on to the Handler. Luckily creating a RouteHandler is easy by implementing the IRouteHandler interface which has only a single GetHttpHandler(RequestContext context) method. In this method you can pick up the requestContext.RouteData, instantiate the HttpHandler of choice, and assign the RouteData to it. Then pass back the handler and you’re done.Here’s a simple example of GetHttpHandler() method that dynamically creates a handler based on a passed in Handler type./// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } Note that this code checks for a specific type of handler and if it matches assigns the RouteData to this handler. This is optional but quite a common scenario if you want to work with RouteData. If the handler you need to instantiate isn’t under your control but you still need to pass RouteData to Handler code, an alternative is to pass the RouteData via the HttpContext.Items collection:IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; requestContext.HttpContext.Items["RouteData"] = requestContext.RouteData; return handler; } The code in the handler implementation can then pick up the RouteData from the context collection as needed:RouteData routeData = HttpContext.Current.Items["RouteData"] as RouteData This isn’t as clean as having an explicit RouteData property, but it does have the advantage that the route data is visible anywhere in the Handler’s code chain. It’s definitely preferable to create a custom property on your handler, but the Context work-around works in a pinch when you don’t’ own the handler code and have dynamic code executing as part of the handler execution. An Example of a Custom RouteHandler: Attribute Based Route Implementation In this post I’m going to discuss a custom routine implementation I built for my CallbackHandler class in the West Wind Web & Ajax Toolkit. CallbackHandler can be very easily used for creating AJAX, REST and POX requests following RPC style method mapping. You can pass parameters via URL query string, POST data or raw data structures, and you can retrieve results as JSON, XML or raw string/binary data. It’s a quick and easy way to build service interfaces with no fuss. As a quick review here’s how CallbackHandler works: You create an Http Handler that derives from CallbackHandler You implement methods that have a [CallbackMethod] Attribute and that’s it. Here’s an example of an CallbackHandler implementation in an ashx.cs based handler:// RestService.ashx.cs public class RestService : CallbackHandler { [CallbackMethod] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } } CallbackHandler makes it super easy to create a method on the server, pass data to it via POST, QueryString or raw JSON/XML data, and then retrieve the results easily back in various formats. This works wonderful and I’ve used these tools in many projects for myself and with clients. But one thing missing has been the ability to create clean URLs. Typical URLs looked like this: http://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuote&symbol=msfthttp://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuotes&symbolList=msft,intc,gld,slw,mwe&format=xml which works and is clear enough, but also clearly very ugly. It would be much nicer if URLs could look like this: http://www.west-wind.com//WestwindWebtoolkit/Samples/StockQuote/msfthttp://www.west-wind.com/WestwindWebtoolkit/Samples/StockQuotes/msft,intc,gld,slw?format=xml (the Virtual Root in this sample is WestWindWebToolkit/Samples and StockQuote/{symbol} is the route)(If you use FireFox try using the JSONView plug-in make it easier to view JSON content) So, taking a clue from the WCF REST tools that use RouteUrls I set out to create a way to specify RouteUrls for each of the endpoints. The change made basically allows changing the above to: [CallbackMethod(RouteUrl="RestService/StockQuote/{symbol}")] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod(RouteUrl = "RestService/StockQuotes/{symbolList}")] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } where a RouteUrl is specified as part of the Callback attribute. And with the changes made with RouteUrls I can now get URLs like the second set shown earlier. So how does that work? Let’s find out… How to Create Custom Routes As mentioned earlier Routing is made up of several steps: Creating a custom RouteHandler to create HttpHandler instances Mapping the actual Routes to the RouteHandler Retrieving the RouteData and actually doing something useful with it in the HttpHandler In the CallbackHandler routing example above this works out to something like this: Create a custom RouteHandler that includes a property to track the method to call Set up the routes using Reflection against the class Looking for any RouteUrls in the CallbackMethod attribute Add a RouteData property to the CallbackHandler so we can access the RouteData in the code of the handler Creating a Custom Route Handler To make the above work I created a custom RouteHandler class that includes the actual IRouteHandler implementation as well as a generic and static method to automatically register all routes marked with the [CallbackMethod(RouteUrl="…")] attribute. Here’s the code:/// <summary> /// Route handler that can create instances of CallbackHandler derived /// callback classes. The route handler tracks the method name and /// creates an instance of the service in a predictable manner /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler type</typeparam> public class CallbackHandlerRouteHandler : IRouteHandler { /// <summary> /// Method name that is to be called on this route. /// Set by the automatically generated RegisterRoutes /// invokation. /// </summary> public string MethodName { get; set; } /// <summary> /// The type of the handler we're going to instantiate. /// Needed so we can semi-generically instantiate the /// handler and call the method on it. /// </summary> public Type CallbackHandlerType { get; set; } /// <summary> /// Constructor to pass in the two required components we /// need to create an instance of our handler. /// </summary> /// <param name="methodName"></param> /// <param name="callbackHandlerType"></param> public CallbackHandlerRouteHandler(string methodName, Type callbackHandlerType) { MethodName = methodName; CallbackHandlerType = callbackHandlerType; } /// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } /// <summary> /// Generic method to register all routes from a CallbackHandler /// that have RouteUrls defined on the [CallbackMethod] attribute /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler Type</typeparam> /// <param name="routes"></param> public static void RegisterRoutes<TCallbackHandler>(RouteCollection routes) { // find all methods var methods = typeof(TCallbackHandler).GetMethods(BindingFlags.Instance | BindingFlags.Public); foreach (var method in methods) { var attrs = method.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (attrs.Length < 1) continue; CallbackMethodAttribute attr = attrs[0] as CallbackMethodAttribute; if (string.IsNullOrEmpty(attr.RouteUrl)) continue; // Add the route routes.Add(method.Name, new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler)))); } } } The RouteHandler implements IRouteHandler, and its responsibility via the GetHandler method is to create an HttpHandler based on the route data. When ASP.NET calls GetHandler it passes a requestContext parameter which includes a requestContext.RouteData property. This parameter holds the current request’s route data as well as an instance of the current RouteHandler. If you look at GetHttpHandler() you can see that the code creates an instance of the handler we are interested in and then sets the RouteData property on the handler. This is how you can pass the current request’s RouteData to the handler. The RouteData object also has a RouteData.RouteHandler property that is also available to the Handler later, which is useful in order to get additional information about the current route. In our case here the RouteHandler includes a MethodName property that identifies the method to execute in the handler since that value no longer comes from the URL so we need to figure out the method name some other way. The method name is mapped explicitly when the RouteHandler is created and here the static method that auto-registers all CallbackMethods with RouteUrls sets the method name when it creates the routes while reflecting over the methods (more on this in a minute). The important point here is that you can attach additional properties to the RouteHandler and you can then later access the RouteHandler and its properties later in the Handler to pick up these custom values. This is a crucial feature in that the RouteHandler serves in passing additional context to the handler so it knows what actions to perform. The automatic route registration is handled by the static RegisterRoutes<TCallbackHandler> method. This method is generic and totally reusable for any CallbackHandler type handler. To register a CallbackHandler and any RouteUrls it has defined you simple use code like this in Application_Start (or other application startup code):protected void Application_Start(object sender, EventArgs e) { // Register Routes for RestService CallbackHandlerRouteHandler.RegisterRoutes<RestService>(RouteTable.Routes); } If you have multiple CallbackHandler style services you can make multiple calls to RegisterRoutes for each of the service types. RegisterRoutes internally uses reflection to run through all the methods of the Handler, looking for CallbackMethod attributes and whether a RouteUrl is specified. If it is a new instance of a CallbackHandlerRouteHandler is created and the name of the method and the type are set. routes.Add(method.Name, new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler) )) ); While the routing with CallbackHandlerRouteHandler is set up automatically for all methods that use the RouteUrl attribute, you can also use code to hook up those routes manually and skip using the attribute. The code for this is straightforward and just requires that you manually map each individual route to each method you want a routed: protected void Application_Start(objectsender, EventArgs e){ RegisterRoutes(RouteTable.Routes);}void RegisterRoutes(RouteCollection routes) { routes.Add("StockQuote Route",new Route("StockQuote/{symbol}", new CallbackHandlerRouteHandler("GetStockQuote",typeof(RestService) ) ) ); routes.Add("StockQuotes Route",new Route("StockQuotes/{symbolList}", new CallbackHandlerRouteHandler("GetStockQuotes",typeof(RestService) ) ) );}I think it’s clearly easier to have CallbackHandlerRouteHandler.RegisterRoutes() do this automatically for you based on RouteUrl attributes, but some people have a real aversion to attaching logic via attributes. Just realize that the option to manually create your routes is available as well. Using the RouteData in the Handler A RouteHandler’s responsibility is to create an HttpHandler and as mentioned earlier, natively IHttpHandler doesn’t have any support for RouteData. In order to utilize RouteData in your handler code you have to pass the RouteData to the handler. In my CallbackHandlerRouteHandler when it creates the HttpHandler instance it creates the instance and then assigns the custom RouteData property on the handler:IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; Again this only works if you actually add a RouteData property to your handler explicitly as I did in my CallbackHandler implementation:/// <summary> /// Optionally store RouteData on this handler /// so we can access it internally /// </summary> public RouteData RouteData {get; set; } and the RouteHandler needs to set it when it creates the handler instance. Once you have the route data in your handler you can access Route Keys and Values and also the RouteHandler. Since my RouteHandler has a custom property for the MethodName to retrieve it from within the handler I can do something like this now to retrieve the MethodName (this example is actually not in the handler but target is an instance pass to the processor): // check for Route Data method name if (target is CallbackHandler) { var routeData = ((CallbackHandler)target).RouteData; if (routeData != null) methodToCall = ((CallbackHandlerRouteHandler)routeData.RouteHandler).MethodName; } When I need to access the dynamic values in the route ( symbol in StockQuote/{symbol}) I can retrieve it easily with the Values collection (RouteData.Values["symbol"]). In my CallbackHandler processing logic I’m basically looking for matching parameter names to Route parameters: // look for parameters in the routeif(routeData != null){ string parmString = routeData.Values[parameter.Name] as string; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType);} And with that we’ve come full circle. We’ve created a custom RouteHandler() that passes the RouteData to the handler it creates. We’ve registered our routes to use the RouteHandler, and we’ve utilized the route data in our handler. For completeness sake here’s the routine that executes a method call based on the parameters passed in and one of the options is to retrieve the inbound parameters off RouteData (as well as from POST data or QueryString parameters):internal object ExecuteMethod(string method, object target, string[] parameters, CallbackMethodParameterType paramType, ref CallbackMethodAttribute callbackMethodAttribute) { HttpRequest Request = HttpContext.Current.Request; object Result = null; // Stores parsed parameters (from string JSON or QUeryString Values) object[] adjustedParms = null; Type PageType = target.GetType(); MethodInfo MI = PageType.GetMethod(method, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic); if (MI == null) throw new InvalidOperationException("Invalid Server Method."); object[] methods = MI.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (methods.Length < 1) throw new InvalidOperationException("Server method is not accessible due to missing CallbackMethod attribute"); if (callbackMethodAttribute != null) callbackMethodAttribute = methods[0] as CallbackMethodAttribute; ParameterInfo[] parms = MI.GetParameters(); JSONSerializer serializer = new JSONSerializer(); RouteData routeData = null; if (target is CallbackHandler) routeData = ((CallbackHandler)target).RouteData; int parmCounter = 0; adjustedParms = new object[parms.Length]; foreach (ParameterInfo parameter in parms) { // Retrieve parameters out of QueryString or POST buffer if (parameters == null) { // look for parameters in the route if (routeData != null) { string parmString = routeData.Values[parameter.Name] as string; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // GET parameter are parsed as plain string values - no JSON encoding else if (HttpContext.Current.Request.HttpMethod == "GET") { // Look up the parameter by name string parmString = Request.QueryString[parameter.Name]; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // POST parameters are treated as methodParameters that are JSON encoded else if (paramType == CallbackMethodParameterType.Json) //string newVariable = methodParameters.GetValue(parmCounter) as string; adjustedParms[parmCounter] = serializer.Deserialize(Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject( Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); } else if (paramType == CallbackMethodParameterType.Json) adjustedParms[parmCounter] = serializer.Deserialize(parameters[parmCounter], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject(parameters[parmCounter], parameter.ParameterType); parmCounter++; } Result = MI.Invoke(target, adjustedParms); return Result; } The code basically uses Reflection to loop through all the parameters available on the method and tries to assign the parameters from RouteData, QueryString or POST variables. The parameters are converted into their appropriate types and then used to eventually make a Reflection based method call. What’s sweet is that the RouteData retrieval is just another option for dealing with the inbound data in this scenario and it adds exactly two lines of code plus the code to retrieve the MethodName I showed previously – a seriously low impact addition that adds a lot of extra value to this endpoint callback processing implementation. Debugging your Routes If you create a lot of routes it’s easy to run into Route conflicts where multiple routes have the same path and overlap with each other. This can be difficult to debug especially if you are using automatically generated routes like the routes created by CallbackHandlerRouteHandler.RegisterRoutes. Luckily there’s a tool that can help you out with this nicely. Phill Haack created a RouteDebugging tool you can download and add to your project. The easiest way to do this is to grab and add this to your project is to use NuGet (Add Library Package from your Project’s Reference Nodes): which adds a RouteDebug assembly to your project. Once installed you can easily debug your routes with this simple line of code which needs to be installed at application startup:protected void Application_Start(object sender, EventArgs e) { CallbackHandlerRouteHandler.RegisterRoutes<StockService>(RouteTable.Routes); // Debug your routes RouteDebug.RouteDebugger.RewriteRoutesForTesting(RouteTable.Routes); } Any routed URL then displays something like this: The screen shows you your current route data and all the routes that are mapped along with a flag that displays which route was actually matched. This is useful – if you have any overlap of routes you will be able to see which routes are triggered – the first one in the sequence wins. This tool has saved my ass on a few occasions – and with NuGet now it’s easy to add it to your project in a few seconds and then remove it when you’re done. Routing Around Custom routing seems slightly complicated on first blush due to its disconnected components of RouteHandler, route registration and mapping of custom handlers. But once you understand the relationship between a RouteHandler, the RouteData and how to pass it to a handler, utilizing of Routing becomes a lot easier as you can easily pass context from the registration to the RouteHandler and through to the HttpHandler. The most important thing to understand when building custom routing solutions is to figure out how to map URLs in such a way that the handler can figure out all the pieces it needs to process the request. This can be via URL routing parameters and as I did in my example by passing additional context information as part of the RouteHandler instance that provides the proper execution context. In my case this ‘context’ was the method name, but it could be an actual static value like an enum identifying an operation or category in an application. Basically user supplied data comes in through the url and static application internal data can be passed via RouteHandler property values. Routing can make your application URLs easier to read by non-techie types regardless of whether you’re building Service type or REST applications, or full on Web interfaces. Routing in ASP.NET 4.0 makes it possible to create just about any extensionless URLs you can dream up and custom RouteHanmdler References Sample ProjectIncludes the sample CallbackHandler service discussed here along with compiled versionsof the Westwind.Web and Westwind.Utilities assemblies. (requires .NET 4.0/VS 2010) West Wind Web Toolkit includes full implementation of CallbackHandler and the Routing Handler West Wind Web Toolkit Source CodeContains the full source code to the Westwind.Web and Westwind.Utilities assemblies usedin these samples. Includes the source described in the post.(Latest build in the Subversion Repository) CallbackHandler Source(Relevant code to this article tree in Westwind.Web assembly) JSONView FireFoxPluginA simple FireFox Plugin to easily view JSON data natively in FireFox.For IE you can use a registry hack to display JSON as raw text.© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET AJAX HTTP

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Red Gate Coder interviews: Alex Davies

- by Michael Williamson

Alex Davies has been a software engineer at Red Gate since graduating from university, and is currently busy working on .NET Demon. We talked about tackling parallel programming with his actors framework, a scientific approach to debugging, and how JavaScript is going to affect the programming languages we use in years to come. So, if we start at the start, how did you get started in programming? When I was seven or eight, I was given a BBC Micro for Christmas. I had asked for a Game Boy, but my dad thought it would be better to give me a proper computer. For a year or so, I only played games on it, but then I found the user guide for writing programs in it. I gradually started doing more stuff on it and found it fun. I liked creating. As I went into senior school I continued to write stuff on there, trying to write games that weren’t very good. I got a real computer when I was fourteen and found ways to write BASIC on it. Visual Basic to start with, and then something more interesting than that. How did you learn to program? Was there someone helping you out? Absolutely not! I learnt out of a book, or by experimenting. I remember the first time I found a loop, I was like “Oh my God! I don’t have to write out the same line over and over and over again any more. It’s amazing!” When did you think this might be something that you actually wanted to do as a career? For a long time, I thought it wasn’t something that you would do as a career, because it was too much fun to be a career. I thought I’d do chemistry at university and some kind of career based on chemical engineering. And then I went to a careers fair at school when I was seventeen or eighteen, and it just didn’t interest me whatsoever. I thought “I could be a programmer, and there’s loads of money there, and I’m good at it, and it’s fun”, but also that I shouldn’t spoil my hobby. Now I don’t really program in my spare time any more, which is a bit of a shame, but I program all the rest of the time, so I can live with it. Do you think you learnt much about programming at university? Yes, definitely! I went into university knowing how to make computers do anything I wanted them to do. However, I didn’t have the language to talk about algorithms, so the algorithms course in my first year was massively important. Learning other language paradigms like functional programming was really good for breadth of understanding. Functional programming influences normal programming through design rather than actually using it all the time. I draw inspiration from it to write imperative programs which I think is actually becoming really fashionable now, but I’ve been doing it for ages. I did it first! There were also some courses on really odd programming languages, a bit of Prolog, a little bit of C. Having a little bit of each of those is something that I would have never done on my own, so it was important. And then there are knowledge-based courses which are about not programming itself but things that have been programmed like TCP. Those are really important for examples for how to approach things. Did you do any internships while you were at university? Yeah, I spent both of my summers at the same company. I thought I could code well before I went there. Looking back at the crap that I produced, it was only surpassed in its crappiness by all of the other code already in that company. I’m so much better at writing nice code now than I used to be back then. Was there just not a culture of looking after your code? There was, they just didn’t hire people for their abilities in that area. They hired people for raw IQ. The first indicator of it going wrong was that they didn’t have any computer scientists, which is a bit odd in a programming company. But even beyond that they didn’t have people who learnt architecture from anyone else. Most of them had started straight out of university, so never really had experience or mentors to learn from. There wasn’t the experience to draw from to teach each other. In the second half of my second internship, I was being given tasks like looking at new technologies and teaching people stuff. Interns shouldn’t be teaching people how to do their jobs! All interns are going to have little nuggets of things that you don’t know about, but they shouldn’t consistently be the ones who know the most. It’s not a good environment to learn. I was going to ask how you found working with people who were more experienced than you… When I reached Red Gate, I found some people who were more experienced programmers than me, and that was difficult. I’ve been coding since I was tiny. At university there were people who were cleverer than me, but there weren’t very many who were more experienced programmers than me. During my internship, I didn’t find anyone who I classed as being a noticeably more experienced programmer than me. So, it was a shock to the system to have valid criticisms rather than just formatting criticisms. However, Red Gate’s not so big on the actual code review, at least it wasn’t when I started. We did an entire product release and then somebody looked over all of the UI of that product which I’d written and say what they didn’t like. By that point, it was way too late and I’d disagree with them. Do you think the lack of code reviews was a bad thing? I think if there’s going to be any oversight of new people, then it should be continuous rather than chunky. For me I don’t mind too much, I could go out and get oversight if I wanted it, and in those situations I felt comfortable without it. If I was managing the new person, then maybe I’d be keener on oversight and then the right way to do it is continuously and in very, very small chunks. Have you had any significant projects you’ve worked on outside of a job? When I was a teenager I wrote all sorts of stuff. I used to write games, I derived how to do isomorphic projections myself once. I didn’t know what the word was so I couldn’t Google for it, so I worked it out myself. It was horrifically complicated. But it sort of tailed off when I started at university, and is now basically zero. If I do side-projects now, they tend to be work-related side projects like my actors framework, NAct, which I started in a down tools week. Could you explain a little more about NAct? It is a little C# framework for writing parallel code more easily. Parallel programming is difficult when you need to write to shared data. Sometimes parallel programming is easy because you don’t need to write to shared data. When you do need to access shared data, you could just have your threads pile in and do their work, but then you would screw up the data because the threads would trample on each other’s toes. You could lock, but locks are really dangerous if you’re using more than one of them. You get interactions like deadlocks, and that’s just nasty. Actors instead allows you to say this piece of data belongs to this thread of execution, and nobody else can read it. If you want to read it, then ask that thread of execution for a piece of it by sending a message, and it will send the data back by a message. And that avoids deadlocks as long as you follow some obvious rules about not making your actors sit around waiting for other actors to do something. There are lots of ways to write actors, NAct allows you to do it as if it was method calls on other objects, which means you get all the strong type-safety that C# programmers like. Do you think that this is suitable for the majority of parallel programming, or do you think it’s only suitable for specific cases? It’s suitable for most difficult parallel programming. If you’ve just got a hundred web requests which are all independent of each other, then I wouldn’t bother because it’s easier to just spin them up in separate threads and they can proceed independently of each other. But where you’ve got difficult parallel programming, where you’ve got multiple threads accessing multiple bits of data in multiple ways at different times, then actors is at least as good as all other ways, and is, I reckon, easier to think about. When you’re using actors, you presumably still have to write your code in a different way from you would otherwise using single-threaded code. You can’t use actors with any methods that have return types, because you’re not allowed to call into another actor and wait for it. If you want to get a piece of data out of another actor, then you’ve got to use tasks so that you can use “async” and “await” to await asynchronously for it. But other than that, you can still stick things in classes so it’s not too different really. Rather than having thousands of objects with mutable state, you can use component-orientated design, where there are only a few mutable classes which each have a small number of instances. Then there can be thousands of immutable objects. If you tend to do that anyway, then actors isn’t much of a jump. If I’ve already built my system without any parallelism, how hard is it to add actors to exploit all eight cores on my desktop? Usually pretty easy. If you can identify even one boundary where things look like messages and you have components where some objects live on one side and these other objects live on the other side, then you can have a granddaddy object on one side be an actor and it will parallelise as it goes across that boundary. Not too difficult. If we do get 1000-core desktop PCs, do you think actors will scale up? It’s hard. There are always in the order of twenty to fifty actors in my whole program because I tend to write each component as actors, and I tend to have one instance of each component. So this won’t scale to a thousand cores. What you can do is write data structures out of actors. I use dictionaries all over the place, and if you need a dictionary that is going to be accessed concurrently, then you could build one of those out of actors in no time. You can use queuing to marshal requests between different slices of the dictionary which are living on different threads. So it’s like a distributed hash table but all of the chunks of it are on the same machine. That means that each of these thousand processors has cached one small piece of the dictionary. I reckon it wouldn’t be too big a leap to start doing proper parallelism. Do you think it helps if actors get baked into the language, similarly to Erlang? Erlang is excellent in that it has thread-local garbage collection. C# doesn’t, so there’s a limit to how well C# actors can possibly scale because there’s a single garbage collected heap shared between all of them. When you do a global garbage collection, you’ve got to stop all of the actors, which is seriously expensive, whereas in Erlang garbage collections happen per-actor, so they’re insanely cheap. However, Erlang deviated from all the sensible language design that people have used recently and has just come up with crazy stuff. You can definitely retrofit thread-local garbage collection to .NET, and then it’s quite well-suited to support actors, even if it’s not baked into the language. Speaking of language design, do you have a favourite programming language? I’ll choose a language which I’ve never written before. I like the idea of Scala. It sounds like C#, only with some of the niggles gone. I enjoy writing static types. It means you don’t have to writing tests so much. When you say it doesn’t have some of the niggles? C# doesn’t allow the use of a property as a method group. It doesn’t have Scala case classes, or sum types, where you can do a switch statement and the compiler checks that you’ve checked all the cases, which is really useful in functional-style programming. Pattern-matching, in other words. That’s actually the major niggle. C# is pretty good, and I’m quite happy with C#. And what about going even further with the type system to remove the need for tests to something like Haskell? Or is that a step too far? I’m quite a pragmatist, I don’t think I could deal with trying to write big systems in languages with too few other users, especially when learning how to structure things. I just don’t know anyone who can teach me, and the Internet won’t teach me. That’s the main reason I wouldn’t use it. If I turned up at a company that writes big systems in Haskell, I would have no objection to that, but I wouldn’t instigate it. What about things in C#? For instance, there’s contracts in C#, so you can try to statically verify a bit more about your code. Do you think that’s useful, or just not worthwhile? I’ve not really tried it. My hunch is that it needs to be built into the language and be quite mathematical for it to work in real life, and that doesn’t seem to have ended up true for C# contracts. I don’t think anyone who’s tried them thinks they’re any good. I might be wrong. On a slightly different note, how do you like to debug code? I think I’m quite an odd debugger. I use guesswork extremely rarely, especially if something seems quite difficult to debug. I’ve been bitten spending hours and hours on guesswork and not being scientific about debugging in the past, so now I’m scientific to a fault. What I want is to see the bug happening in the debugger, to step through the bug happening. To watch the program going from a valid state to an invalid state. When there’s a bug and I can’t work out why it’s happening, I try to find some piece of evidence which places the bug in one section of the code. From that experiment, I binary chop on the possible causes of the bug. I suppose that means binary chopping on places in the code, or binary chopping on a stage through a processing cycle. Basically, I’m very stupid about how I debug. I won’t make any guesses, I won’t use any intuition, I will only identify the experiment that’s going to binary chop most effectively and repeat rather than trying to guess anything. I suppose it’s quite top-down. Is most of the time then spent in the debugger? Absolutely, if at all possible I will never debug using print statements or logs. I don’t really hold much stock in outputting logs. If there’s any bug which can be reproduced locally, I’d rather do it in the debugger than outputting logs. And with SmartAssembly error reporting, there’s not a lot that can’t be either observed in an error report and just fixed, or reproduced locally. And in those other situations, maybe I’ll use logs. But I hate using logs. You stare at the log, trying to guess what’s going on, and that’s exactly what I don’t like doing. You have to just look at it and see does this look right or wrong. We’ve covered how you get to grip with bugs. How do you get to grips with an entire codebase? I watch it in the debugger. I find little bugs and then try to fix them, and mostly do it by watching them in the debugger and gradually getting an understanding of how the code works using my process of binary chopping. I have to do a lot of reading and watching code to choose where my slicing-in-half experiment is going to be. The last time I did it was SmartAssembly. The old code was a complete mess, but at least it did things top to bottom. There wasn’t too much of some of the big abstractions where flow of control goes all over the place, into a base class and back again. Code’s really hard to understand when that happens. So I like to choose a little bug and try to fix it, and choose a bigger bug and try to fix it. Definitely learn by doing. I want to always have an aim so that I get a little achievement after every few hours of debugging. Once I’ve learnt the codebase I might be able to fix all the bugs in an hour, but I’d rather be using them as an aim while I’m learning the codebase. If I was a maintainer of a codebase, what should I do to make it as easy as possible for you to understand? Keep distinct concepts in different places. And name your stuff so that it’s obvious which concepts live there. You shouldn’t have some variable that gets set miles up the top of somewhere, and then is read miles down to choose some later behaviour. I’m talking from a very much SmartAssembly point of view because the old SmartAssembly codebase had tons and tons of these things, where it would read some property of the code and then deal with it later. Just thousands of variables in scope. Loads of things to think about. If you can keep concepts separate, then it aids me in my process of fixing bugs one at a time, because each bug is going to more or less be understandable in the one place where it is. And what about tests? Do you think they help at all? I’ve never had the opportunity to learn a codebase which has had tests, I don’t know what it’s like! What about when you’re actually developing? How useful do you find tests in finding bugs or regressions? Finding regressions, absolutely. Running bits of code that would be quite hard to run otherwise, definitely. It doesn’t happen very often that a test finds a bug in the first place. I don’t really buy nebulous promises like tests being a good way to think about the spec of the code. My thinking goes something like “This code works at the moment, great, ship it! Ah, there’s a way that this code doesn’t work. Okay, write a test, demonstrate that it doesn’t work, fix it, use the test to demonstrate that it’s now fixed, and keep the test for future regressions.” The most valuable tests are for bugs that have actually happened at some point, because bugs that have actually happened at some point, despite the fact that you think you’ve fixed them, are way more likely to appear again than new bugs are. Does that mean that when you write your code the first time, there are no tests? Often. The chance of there being a bug in a new feature is relatively unaffected by whether I’ve written a test for that new feature because I’m not good enough at writing tests to think of bugs that I would have written into the code. So not writing regression tests for all of your code hasn’t affected you too badly? There are different kinds of features. Some of them just always work, and are just not flaky, they just continue working whatever you throw at them. Maybe because the type-checker is particularly effective around them. Writing tests for those features which just tend to always work is a waste of time. And because it’s a waste of time I’ll tend to wait until a feature has demonstrated its flakiness by having bugs in it before I start trying to test it. You can get a feel for whether it’s going to be flaky code as you’re writing it. I try to write it to make it not flaky, but there are some things that are just inherently flaky. And very occasionally, I’ll think “this is going to be flaky” as I’m writing, and then maybe do a test, but not most of the time. How do you think your programming style has changed over time? I’ve got clearer about what the right way of doing things is. I used to flip-flop a lot between different ideas. Five years ago I came up with some really good ideas and some really terrible ideas. All of them seemed great when I thought of them, but they were quite diverse ideas, whereas now I have a smaller set of reliable ideas that are actually good for structuring code. So my code is probably more similar to itself than it used to be back in the day, when I was trying stuff out. I’ve got more disciplined about encapsulation, I think. There are operational things like I use actors more now than I used to, and that forces me to use immutability more than I used to. The first code that I wrote in Red Gate was the memory profiler UI, and that was an actor, I just didn’t know the name of it at the time. I don’t really use object-orientation. By object-orientation, I mean having n objects of the same type which are mutable. I want a constant number of objects that are mutable, and they should be different types. I stick stuff in dictionaries and then have one thing that owns the dictionary and puts stuff in and out of it. That’s definitely a pattern that I’ve seen recently. I think maybe I’m doing functional programming. Possibly. It’s plausible. If you had to summarise the essence of programming in a pithy sentence, how would you do it? Programming is the form of art that, without losing any of the beauty of architecture or fine art, allows you to produce things that people love and you make money from. So you think it’s an art rather than a science? It’s a little bit of engineering, a smidgeon of maths, but it’s not science. Like architecture, programming is on that boundary between art and engineering. If you want to do it really nicely, it’s mostly art. You can get away with doing architecture and programming entirely by having a good engineering mind, but you’re not going to produce anything nice. You’re not going to have joy doing it if you’re an engineering mind. Architects who are just engineering minds are not going to enjoy their job. I suppose engineering is the foundation on which you build the art. Exactly. How do you think programming is going to change over the next ten years? There will be an unfortunate shift towards dynamically-typed languages, because of JavaScript. JavaScript has an unfair advantage. JavaScript’s unfair advantage will cause more people to be exposed to dynamically-typed languages, which means other dynamically-typed languages crop up and the best features go into dynamically-typed languages. Then people conflate the good features with the fact that it’s dynamically-typed, and more investment goes into dynamically-typed languages. They end up better, so people use them. What about the idea of compiling other languages, possibly statically-typed, to JavaScript? It’s a reasonable idea. I would like to do it, but I don’t think enough people in the world are going to do it to make it pick up. The hordes of beginners are the lifeblood of a language community. They are what makes there be good tools and what makes there be vibrant community websites. And any particular thing which is the same as JavaScript only with extra stuff added to it, although it might be technically great, is not going to have the hordes of beginners. JavaScript is always to be quickest and easiest way for a beginner to start programming in the browser. And dynamically-typed languages are great for beginners. Compilers are pretty scary and beginners don’t write big code. And having your errors come up in the same place, whether they’re statically checkable errors or not, is quite nice for a beginner. If someone asked me to teach them some programming, I’d teach them JavaScript. If dynamically-typed languages are great for beginners, when do you think the benefits of static typing start to kick in? The value of having a statically typed program is in the tools that rely on the static types to produce a smooth IDE experience rather than actually telling me my compile errors. And only once you’re experienced enough a programmer that having a really smooth IDE experience makes a blind bit of difference, does static typing make a blind bit of difference. So it’s not really about size of codebase. If I go and write up a tiny program, I’m still going to get value out of writing it in C# using ReSharper because I’m experienced with C# and ReSharper enough to be able to write code five times faster if I have that help. Any other visions of the future? Nobody’s going to use actors. Because everyone’s going to be running on single-core VMs connected over network-ready protocols like JSON over HTTP. So, parallelism within one operating system is going to die. But until then, you should use actors. More Red Gater Coder interviews

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Silverlight for Windows Embedded tutorial (step 4)

- by Valter Minute

I’m back with my Silverlight for Windows Embedded tutorial. Sorry for the long delay between step 3 and step 4, the MVP summit and some work related issue prevented me from working on the tutorial during the last weeks. In our first, second and third tutorial steps we implemented some very simple applications, just to understand the basic structure of a Silverlight for Windows Embedded application, learn how to handle events and how to operate on images. In this third step our sample application will be slightly more complicated, to introduce two new topics: list boxes and custom control. We will also learn how to create controls at runtime. I choose to explain those topics together and provide a sample a bit more complicated than usual just to start to give the feeling of how a “real” Silverlight for Windows Embedded application is organized. As usual we can start using Expression Blend to define our main page. In this case we will have a listbox and a textblock. Here’s the XAML code: <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" x:Class="ListDemo.Page" Width="640" Height="480" x:Name="ListPage" xmlns:ListDemo="clr-namespace:ListDemo"> <Grid x:Name="LayoutRoot" Background="White"> <ListBox Margin="19,57,19,66" x:Name="FileList" SelectionChanged="Filelist_SelectionChanged"/> <TextBlock Height="35" Margin="19,8,19,0" VerticalAlignment="Top" TextWrapping="Wrap" x:Name="CurrentDir" Text="TextBlock" FontSize="20"/> </Grid> </UserControl> In our listbox we will load a list of directories, starting from the filesystem root (there are no drives in Windows CE, the filesystem has a single root named “\”). When the user clicks on an item inside the list, the corresponding directory path will be displayed in the TextBlock object and the subdirectories of the selected branch will be shown inside the list. As you can see we declared an event handler for the SelectionChanged event of our listbox. We also used a different font size for the TextBlock, to make it more readable. XAML and Expression Blend allow you to customize your UI pretty heavily, experiment with the tools and discover how you can completely change the aspect of your application without changing a single line of code! Inside our ListBox we want to insert the directory presenting a nice icon and their name, just like you are used to see them inside Windows 7 file explorer, for example. To get this we will define a user control. This is a custom object that will behave like “regular” Silverlight for Windows Embedded objects inside our application. First of all we have to define the look of our custom control, named DirectoryItem, using XAML: <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" x:Class="ListDemo.DirectoryItem" Width="500" Height="80"> <StackPanel x:Name="LayoutRoot" Orientation="Horizontal"> <Canvas Width="31.6667" Height="45.9583" Margin="10,10,10,10" RenderTransformOrigin="0.5,0.5"> <Canvas.RenderTransform> <TransformGroup> <ScaleTransform/> <SkewTransform/> <RotateTransform Angle="-31.27"/> <TranslateTransform/> </TransformGroup> </Canvas.RenderTransform> <Rectangle Width="31.6667" Height="45.8414" Canvas.Left="0" Canvas.Top="0.116943" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142631,0.75344" EndPoint="1.01886,0.75344"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142631" CenterY="0.75344" AngleX="19.3128" AngleY="0"/> <RotateTransform CenterX="0.142631" CenterY="0.75344" Angle="-35.3436"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FF7B6802" Offset="0"/> <GradientStop Color="#FFF3D42C" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="29.8441" Height="43.1517" Canvas.Left="0.569519" Canvas.Top="1.05249" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142632,0.753441" EndPoint="1.01886,0.753441"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142632" CenterY="0.753441" AngleX="19.3127" AngleY="0"/> <RotateTransform CenterX="0.142632" CenterY="0.753441" Angle="-35.3437"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FFCDCDCD" Offset="0.0833333"/> <GradientStop Color="#FFFFFFFF" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="29.8441" Height="43.1517" Canvas.Left="0.455627" Canvas.Top="2.28036" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142631,0.75344" EndPoint="1.01886,0.75344"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142631" CenterY="0.75344" AngleX="19.3128" AngleY="0"/> <RotateTransform CenterX="0.142631" CenterY="0.75344" Angle="-35.3436"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FFCDCDCD" Offset="0.0833333"/> <GradientStop Color="#FFFFFFFF" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="29.8441" Height="43.1517" Canvas.Left="0.455627" Canvas.Top="1.34485" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142631,0.75344" EndPoint="1.01886,0.75344"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142631" CenterY="0.75344" AngleX="19.3128" AngleY="0"/> <RotateTransform CenterX="0.142631" CenterY="0.75344" Angle="-35.3436"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FFCDCDCD" Offset="0.0833333"/> <GradientStop Color="#FFFFFFFF" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="26.4269" Height="45.8414" Canvas.Left="0.227798" Canvas.Top="0" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142631,0.75344" EndPoint="1.01886,0.75344"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142631" CenterY="0.75344" AngleX="19.3127" AngleY="0"/> <RotateTransform CenterX="0.142631" CenterY="0.75344" Angle="-35.3436"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FF7B6802" Offset="0"/> <GradientStop Color="#FFF3D42C" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="1.25301" Height="45.8414" Canvas.Left="1.70862" Canvas.Top="0.116943" Stretch="Fill" Fill="#FFEBFF07"/> </Canvas> <TextBlock Height="80" x:Name="Name" Width="448" TextWrapping="Wrap" VerticalAlignment="Center" FontSize="24" Text="Directory"/> </StackPanel> </UserControl> As you can see, this XAML contains many graphic elements. Those elements are used to design the folder icon. The original drawing has been designed in Expression Design and then exported as XAML. In Silverlight for Windows Embedded you can use vector images. This means that your images will look good even when scaled or rotated. In our DirectoryItem custom control we have a TextBlock named Name, that will be used to display….(suspense)…. the directory name (I’m too lazy to invent fancy names for controls, and using “boring” intuitive names will make code more readable, I hope!). Now that we have some XAML code, we may execute XAML2CPP to generate part of the aplication code for us. We should then add references to our XAML2CPP generated resource file and include in our code and add a reference to the XAML runtime library to our sources file (you can follow the instruction of the first tutorial step to do that), To generate the code used in this tutorial you need XAML2CPP ver 1.0.1.0, that is downloadable here: http://geekswithblogs.net/WindowsEmbeddedCookbook/archive/2010/03/08/xaml2cpp-1.0.1.0.aspx We can now create our usual simple Win32 application inside Platform Builder, using the same step described in the first chapter of this tutorial (http://geekswithblogs.net/WindowsEmbeddedCookbook/archive/2009/10/01/silverlight-for-embedded-tutorial.aspx). We can declare a class for our main page, deriving it from the template that XAML2CPP generated for us: class ListPage : public TListPage<ListPage> { ... } We will see the ListPage class code in a short time, but before we will see the code of our DirectoryItem user control. This object will be used to populate our list, one item for each directory. To declare a user control things are a bit more complicated (but also in this case XAML2CPP will write most of the “boilerplate” code for use. To interact with a user control you should declare an interface. An interface defines the functions of a user control that can be called inside the application code. Our custom control is currently quite simple and we just need some member functions to store and retrieve a full pathname inside our control. The control will display just the last part of the path inside the control. An interface is declared as a C++ class that has only abstract virtual members. It should also have an UUID associated with it. UUID means Universal Unique IDentifier and it’s a 128 bit number that will identify our interface without the need of specifying its fully qualified name. UUIDs are used to identify COM interfaces and, as we discovered in chapter one, Silverlight for Windows Embedded is based on COM or, at least, provides a COM-like Application Programming Interface (API). Here’s the declaration of the DirectoryItem interface: class __declspec(novtable,uuid("{D38C66E5-2725-4111-B422-D75B32AA8702}")) IDirectoryItem : public IXRCustomUserControl { public: virtual HRESULT SetFullPath(BSTR fullpath) = 0; virtual HRESULT GetFullPath(BSTR* retval) = 0; }; The interface is derived from IXRCustomControl, this will allow us to add our object to a XAML tree. It declares the two functions needed to set and get the full path, but don’t implement them. Implementation will be done inside the control class. The interface only defines the functions of our control class that are accessible from the outside. It’s a sort of “contract” between our control and the applications that will use it. We must support what’s inside the contract and the application code should know nothing else about our own control. To reference our interface we will use the UUID, to make code more readable we can declare a #define in this way: #define IID_IDirectoryItem __uuidof(IDirectoryItem) Silverlight for Windows Embedded objects (like COM objects) use a reference counting mechanism to handle object destruction. Every time you store a pointer to an object you should call its AddRef function and every time you no longer need that pointer you should call Release. The object keeps an internal counter, incremented for each AddRef and decremented on Release. When the counter reaches 0, the object is destroyed. Managing reference counting in our code can be quite complicated and, since we are lazy (I am, at least!), we will use a great feature of Silverlight for Windows Embedded: smart pointers.A smart pointer can be connected to a Silverlight for Windows Embedded object and manages its reference counting. To declare a smart pointer we must use the XRPtr template: typedef XRPtr<IDirectoryItem> IDirectoryItemPtr; Now that we have defined our interface, it’s time to implement our user control class. XAML2CPP has implemented a class for us, and we have only to derive our class from it, defining the main class and interface of our new custom control: class DirectoryItem : public DirectoryItemUserControlRegister<DirectoryItem,IDirectoryItem> { ... } XAML2CPP has generated some code for us to support the user control, we don’t have to mind too much about that code, since it will be generated (or written by hand, if you like) always in the same way, for every user control. But knowing how does this works “under the hood” is still useful to understand the architecture of Silverlight for Windows Embedded. Our base class declaration is a bit more complex than the one we used for a simple page in the previous chapters: template <class A,class B> class DirectoryItemUserControlRegister : public XRCustomUserControlImpl<A,B>,public TDirectoryItem<A,XAML2CPPUserControl> { ... } This class derives from the XAML2CPP generated template class, like the ListPage class, but it uses XAML2CPPUserControl for the implementation of some features. This class shares the same ancestor of XAML2CPPPage (base class for “regular” XAML pages), XAML2CPPBase, implements binding of member variables and event handlers but, instead of loading and creating its own XAML tree, it attaches to an existing one. The XAML tree (and UI) of our custom control is created and loaded by the XRCustomUserControlImpl class. This class is part of the Silverlight for Windows Embedded framework and implements most of the functions needed to build-up a custom control in Silverlight (the guys that developed Silverlight for Windows Embedded seem to care about lazy programmers!). We have just to initialize it, providing our class (DirectoryItem) and interface (IDirectoryItem). Our user control class has also a static member: protected: static HINSTANCE hInstance; This is used to store the HINSTANCE of the modules that contain our user control class. I don’t like this implementation, but I can’t find a better one, so if somebody has good ideas about how to handle the HINSTANCE object, I’ll be happy to hear suggestions! It also implements two static members required by XRCustomUserControlImpl. The first one is used to load the XAML UI of our custom control: static HRESULT GetXamlSource(XRXamlSource* pXamlSource) { pXamlSource->SetResource(hInstance,TEXT("XAML"),IDR_XAML_DirectoryItem); return S_OK; } It initializes a XRXamlSource object, connecting it to the XAML resource that XAML2CPP has included in our resource script. The other method is used to register our custom control, allowing Silverlight for Windows Embedded to create it when it load some XAML or when an application creates a new control at runtime (more about this later): static HRESULT Register() { return XRCustomUserControlImpl<A,B>::Register(__uuidof(B), L"DirectoryItem", L"clr-namespace:DirectoryItemNamespace"); } To register our control we should provide its interface UUID, the name of the corresponding element in the XAML tree and its current namespace (namespaces compatible with Silverlight must use the “clr-namespace” prefix. We may also register additional properties for our objects, allowing them to be loaded and saved inside XAML. In this case we have no permanent properties and the Register method will just register our control. An additional static method is implemented to allow easy registration of our custom control inside our application WinMain function: static HRESULT RegisterUserControl(HINSTANCE hInstance) { DirectoryItemUserControlRegister::hInstance=hInstance; return DirectoryItemUserControlRegister<A,B>::Register(); } Now our control is registered and we will be able to create it using the Silverlight for Windows Embedded runtime functions. But we need to bind our members and event handlers to have them available like we are used to do for other XAML2CPP generated objects. To bind events and members we need to implement the On_Loaded function: virtual HRESULT OnLoaded(__in IXRDependencyObject* pRoot) { HRESULT retcode; IXRApplicationPtr app; if (FAILED(retcode=GetXRApplicationInstance(&app))) return retcode; return ((A*)this)->Init(pRoot,hInstance,app); } This function will call the XAML2CPPUserControl::Init member that will connect the “root” member with the XAML sub tree that has been created for our control and then calls BindObjects and BindEvents to bind members and events to our code. Now we can go back to our application code (the code that you’ll have to actually write) to see the contents of our DirectoryItem class: class DirectoryItem : public DirectoryItemUserControlRegister<DirectoryItem,IDirectoryItem> { protected: WCHAR fullpath[_MAX_PATH+1]; public: DirectoryItem() { *fullpath=0; } virtual HRESULT SetFullPath(BSTR fullpath) { wcscpy_s(this->fullpath,fullpath); WCHAR* p=fullpath; for(WCHAR*q=wcsstr(p,L"\\");q;p=q+1,q=wcsstr(p,L"\\")) ; Name->SetText(p); return S_OK; } virtual HRESULT GetFullPath(BSTR* retval) { *retval=SysAllocString(fullpath); return S_OK; } }; It’s pretty easy and contains a fullpath member (used to store that path of the directory connected with the user control) and the implementation of the two interface members that can be used to set and retrieve the path. The SetFullPath member parses the full path and displays just the last branch directory name inside the “Name” TextBlock object. As you can see, implementing a user control in Silverlight for Windows Embedded is not too complex and using XAML also for the UI of the control allows us to re-use the same mechanisms that we learnt and used in the previous steps of our tutorial. Now let’s see how the main page is managed by the ListPage class. class ListPage : public TListPage<ListPage> { protected: // current path TCHAR curpath[_MAX_PATH+1]; It has a member named “curpath” that is used to store the current directory. It’s initialized inside the constructor: ListPage() { *curpath=0; } And it’s value is displayed inside the “CurrentDir” TextBlock inside the initialization function: virtual HRESULT Init(HINSTANCE hInstance,IXRApplication* app) { HRESULT retcode; if (FAILED(retcode=TListPage<ListPage>::Init(hInstance,app))) return retcode; CurrentDir->SetText(L"\\"); return S_OK; } The FillFileList function is used to enumerate subdirectories of the current dir and add entries for each one inside the list box that fills most of the client area of our main page: HRESULT FillFileList() { HRESULT retcode; IXRItemCollectionPtr items; IXRApplicationPtr app; if (FAILED(retcode=GetXRApplicationInstance(&app))) return retcode; // retrieves the items contained in the listbox if (FAILED(retcode=FileList->GetItems(&items))) return retcode; // clears the list if (FAILED(retcode=items->Clear())) return retcode; // enumerates files and directory in the current path WCHAR filemask[_MAX_PATH+1]; wcscpy_s(filemask,curpath); wcscat_s(filemask,L"\\*.*"); WIN32_FIND_DATA finddata; HANDLE findhandle; findhandle=FindFirstFile(filemask,&finddata); // the directory is empty? if (findhandle==INVALID_HANDLE_VALUE) return S_OK; do { if (finddata.dwFileAttributes&=FILE_ATTRIBUTE_DIRECTORY) { IXRListBoxItemPtr listboxitem; // add a new item to the listbox if (FAILED(retcode=app->CreateObject(IID_IXRListBoxItem,&listboxitem))) { FindClose(findhandle); return retcode; } if (FAILED(retcode=items->Add(listboxitem,NULL))) { FindClose(findhandle); return retcode; } IDirectoryItemPtr directoryitem; if (FAILED(retcode=app->CreateObject(IID_IDirectoryItem,&directoryitem))) { FindClose(findhandle); return retcode; } WCHAR fullpath[_MAX_PATH+1]; wcscpy_s(fullpath,curpath); wcscat_s(fullpath,L"\\"); wcscat_s(fullpath,finddata.cFileName); if (FAILED(retcode=directoryitem->SetFullPath(fullpath))) { FindClose(findhandle); return retcode; } XAML2CPPXRValue value((IXRDependencyObject*)directoryitem); if (FAILED(retcode=listboxitem->SetContent(&value))) { FindClose(findhandle); return retcode; } } } while (FindNextFile(findhandle,&finddata)); FindClose(findhandle); return S_OK; } This functions retrieve a pointer to the collection of the items contained in the directory listbox. The IXRItemCollection interface is used by listboxes and comboboxes and allow you to clear the list (using Clear(), as our function does at the beginning) and change its contents by adding and removing elements. This function uses the FindFirstFile/FindNextFile functions to enumerate all the objects inside our current directory and for each subdirectory creates a IXRListBoxItem object. You can insert any kind of control inside a list box, you don’t need a IXRListBoxItem, but using it will allow you to handle the selected state of an item, highlighting it inside the list. The function creates a list box item using the CreateObject function of XRApplication. The same function is then used to create an instance of our custom control. The function returns a pointer to the control IDirectoryItem interface and we can use it to store the directory full path inside the object and add it as content of the IXRListBox item object, adding it to the listbox contents. The listbox generates an event (SelectionChanged) each time the user clicks on one of the items contained in the listbox. We implement an event handler for that event and use it to change our current directory and repopulate the listbox. The current directory full path will be displayed in the TextBlock: HRESULT Filelist_SelectionChanged(IXRDependencyObject* source,XRSelectionChangedEventArgs* args) { HRESULT retcode; IXRListBoxItemPtr listboxitem; if (!args->pAddedItem) return S_OK; if (FAILED(retcode=args->pAddedItem->QueryInterface(IID_IXRListBoxItem,(void**)&listboxitem))) return retcode; XRValue content; if (FAILED(retcode=listboxitem->GetContent(&content))) return retcode; if (content.vType!=VTYPE_OBJECT) return E_FAIL; IDirectoryItemPtr directoryitem; if (FAILED(retcode=content.pObjectVal->QueryInterface(IID_IDirectoryItem,(void**)&directoryitem))) return retcode; content.pObjectVal->Release(); content.pObjectVal=NULL; BSTR fullpath=NULL; if (FAILED(retcode=directoryitem->GetFullPath(&fullpath))) return retcode; CurrentDir->SetText(fullpath); wcscpy_s(curpath,fullpath); FillFileList(); SysFreeString(fullpath); return S_OK; } }; The function uses the pAddedItem member of the XRSelectionChangedEventArgs object to retrieve the currently selected item, converts it to a IXRListBoxItem interface using QueryInterface, and then retrives its contents (IDirectoryItem object). Using the GetFullPath method we can get the full path of our selected directory and assing it to the curdir member. A call to FillFileList will update the listbox contents, displaying the list of subdirectories of the selected folder. To build our sample we just need to add code to our WinMain function: int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow) { if (!XamlRuntimeInitialize()) return -1; HRESULT retcode; IXRApplicationPtr app; if (FAILED(retcode=GetXRApplicationInstance(&app))) return -1; if (FAILED(retcode=DirectoryItem::RegisterUserControl(hInstance))) return retcode; ListPage page; if (FAILED(page.Init(hInstance,app))) return -1; page.FillFileList(); UINT exitcode; if (FAILED(page.GetVisualHost()->StartDialog(&exitcode))) return -1; return 0; } This code is very similar to the one of the WinMains of our previous samples. The main differences are that we register our custom control (you should do that as soon as you have initialized the XAML runtime) and call FillFileList after the initialization of our ListPage object to load the contents of the root folder of our device inside the listbox. As usual you can download the full sample source code from here: http://cid-9b7b0aefe3514dc5.skydrive.live.com/self.aspx/.Public/ListBoxTest.zip

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Silverlight Recruiting Application Part 5 - Jobs Module / View

Now we starting getting into a more code-heavy portion of this series, thankfully though this means the groundwork is all set for the most part and after adding the modules we will have a complete application that can be provided with full source. The Jobs module will have two concerns- adding and maintaining jobs that can then be broadcast out to the website. How they are displayed on the site will be handled by our admin system (which will just poll from this common database), so we aren't too concerned with that, but rather with getting the information into the system and allowing the backend administration/HR users to keep things up to date. Since there is a fair bit of information that we want to display, we're going to move editing to a separate view so we can get all that information in an easy-to-use spot. With all the files created for this module, the project looks something like this: And now... on to the code. XAML for the Job Posting View All we really need for the Job Posting View is a RadGridView and a few buttons. This will let us both show off records and perform operations on the records without much hassle. That XAML is going to look something like this: 01.<Grid x:Name="LayoutRoot" 02.Background="White"> 03.<Grid.RowDefinitions> 04.<RowDefinition Height="30" /> 05.<RowDefinition /> 06.</Grid.RowDefinitions> 07.<StackPanel Orientation="Horizontal"> 08.<Button x:Name="xAddRecordButton" 09.Content="Add Job" 10.Width="120" 11.cal:Click.Command="{Binding AddRecord}" 12.telerik:StyleManager.Theme="Windows7" /> 13.<Button x:Name="xEditRecordButton" 14.Content="Edit Job" 15.Width="120" 16.cal:Click.Command="{Binding EditRecord}" 17.telerik:StyleManager.Theme="Windows7" /> 18.</StackPanel> 19.<telerikGrid:RadGridView x:Name="xJobsGrid" 20.Grid.Row="1" 21.IsReadOnly="True" 22.AutoGenerateColumns="False" 23.ColumnWidth="*" 24.RowDetailsVisibilityMode="VisibleWhenSelected" 25.ItemsSource="{Binding MyJobs}" 26.SelectedItem="{Binding SelectedJob, Mode=TwoWay}" 27.command:SelectedItemChangedEventClass.Command="{Binding SelectedItemChanged}"> 28.<telerikGrid:RadGridView.Columns> 29.<telerikGrid:GridViewDataColumn Header="Job Title" 30.DataMemberBinding="{Binding JobTitle}" 31.UniqueName="JobTitle" /> 32.<telerikGrid:GridViewDataColumn Header="Location" 33.DataMemberBinding="{Binding Location}" 34.UniqueName="Location" /> 35.<telerikGrid:GridViewDataColumn Header="Resume Required" 36.DataMemberBinding="{Binding NeedsResume}" 37.UniqueName="NeedsResume" /> 38.<telerikGrid:GridViewDataColumn Header="CV Required" 39.DataMemberBinding="{Binding NeedsCV}" 40.UniqueName="NeedsCV" /> 41.<telerikGrid:GridViewDataColumn Header="Overview Required" 42.DataMemberBinding="{Binding NeedsOverview}" 43.UniqueName="NeedsOverview" /> 44.<telerikGrid:GridViewDataColumn Header="Active" 45.DataMemberBinding="{Binding IsActive}" 46.UniqueName="IsActive" /> 47.</telerikGrid:RadGridView.Columns> 48.</telerikGrid:RadGridView> 49.</Grid> I'll explain what's happening here by line numbers: Lines 11 and 16: Using the same type of click commands as we saw in the Menu module, we tie the button clicks to delegate commands in the viewmodel. Line 25: The source for the jobs will be a collection in the viewmodel. Line 26: We also bind the selected item to a public property from the viewmodel for use in code. Line 27: We've turned the event into a command so we can handle it via code in the viewmodel. So those first three probably make sense to you as far as Silverlight/WPF binding magic is concerned, but for line 27... This actually comes from something I read onDamien Schenkelman's blog back in the day for creating an attached behavior from any event. So, any time you see me using command:Whatever.Command, the backing for it is actually something like this: SelectedItemChangedEventBehavior.cs: 01.public class SelectedItemChangedEventBehavior : CommandBehaviorBase<Telerik.Windows.Controls.DataControl> 02.{ 03.public SelectedItemChangedEventBehavior(DataControl element) 04.: base(element) 05.{ 06.element.SelectionChanged += new EventHandler<SelectionChangeEventArgs>(element_SelectionChanged); 07.} 08.void element_SelectionChanged(object sender, SelectionChangeEventArgs e) 09.{ 10.// We'll only ever allow single selection, so will only need item index 0 11.base.CommandParameter = e.AddedItems[0]; 12.base.ExecuteCommand(); 13.} 14.} SelectedItemChangedEventClass.cs: 01.public class SelectedItemChangedEventClass 02.{ 03.#region The Command Stuff 04.public static ICommand GetCommand(DependencyObject obj) 05.{ 06.return (ICommand)obj.GetValue(CommandProperty); 07.} 08.public static void SetCommand(DependencyObject obj, ICommand value) 09.{ 10.obj.SetValue(CommandProperty, value); 11.} 12.public static readonly DependencyProperty CommandProperty = 13.DependencyProperty.RegisterAttached("Command", typeof(ICommand), 14.typeof(SelectedItemChangedEventClass), new PropertyMetadata(OnSetCommandCallback)); 15.public static void OnSetCommandCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e) 16.{ 17.DataControl element = dependencyObject as DataControl; 18.if (element != null) 19.{ 20.SelectedItemChangedEventBehavior behavior = GetOrCreateBehavior(element); 21.behavior.Command = e.NewValue as ICommand; 22.} 23.} 24.#endregion 25.public static SelectedItemChangedEventBehavior GetOrCreateBehavior(DataControl element) 26.{ 27.SelectedItemChangedEventBehavior behavior = element.GetValue(SelectedItemChangedEventBehaviorProperty) as SelectedItemChangedEventBehavior; 28.if (behavior == null) 29.{ 30.behavior = new SelectedItemChangedEventBehavior(element); 31.element.SetValue(SelectedItemChangedEventBehaviorProperty, behavior); 32.} 33.return behavior; 34.} 35.public static SelectedItemChangedEventBehavior GetSelectedItemChangedEventBehavior(DependencyObject obj) 36.{ 37.return (SelectedItemChangedEventBehavior)obj.GetValue(SelectedItemChangedEventBehaviorProperty); 38.} 39.public static void SetSelectedItemChangedEventBehavior(DependencyObject obj, SelectedItemChangedEventBehavior value) 40.{ 41.obj.SetValue(SelectedItemChangedEventBehaviorProperty, value); 42.} 43.public static readonly DependencyProperty SelectedItemChangedEventBehaviorProperty = 44.DependencyProperty.RegisterAttached("SelectedItemChangedEventBehavior", 45.typeof(SelectedItemChangedEventBehavior), typeof(SelectedItemChangedEventClass), null); 46.} These end up looking very similar from command to command, but in a nutshell you create a command based on any event, determine what the parameter for it will be, then execute. It attaches via XAML and ties to a DelegateCommand in the viewmodel, so you get the full event experience (since some controls get a bit event-rich for added functionality). Simple enough, right? Viewmodel for the Job Posting View The Viewmodel is going to need to handle all events going back and forth, maintaining interactions with the data we are using, and both publishing and subscribing to events. Rather than breaking this into tons of little pieces, I'll give you a nice view of the entire viewmodel and then hit up the important points line-by-line: 001.public class JobPostingViewModel : ViewModelBase 002.{ 003.private readonly IEventAggregator eventAggregator; 004.private readonly IRegionManager regionManager; 005.public DelegateCommand<object> AddRecord { get; set; } 006.public DelegateCommand<object> EditRecord { get; set; } 007.public DelegateCommand<object> SelectedItemChanged { get; set; } 008.public RecruitingContext context; 009.private QueryableCollectionView _myJobs; 010.public QueryableCollectionView MyJobs 011.{ 012.get { return _myJobs; } 013.} 014.private QueryableCollectionView _selectionJobActionHistory; 015.public QueryableCollectionView SelectedJobActionHistory 016.{ 017.get { return _selectionJobActionHistory; } 018.} 019.private JobPosting _selectedJob; 020.public JobPosting SelectedJob 021.{ 022.get { return _selectedJob; } 023.set 024.{ 025.if (value != _selectedJob) 026.{ 027._selectedJob = value; 028.NotifyChanged("SelectedJob"); 029.} 030.} 031.} 032.public SubscriptionToken editToken = new SubscriptionToken(); 033.public SubscriptionToken addToken = new SubscriptionToken(); 034.public JobPostingViewModel(IEventAggregator eventAgg, IRegionManager regionmanager) 035.{ 036.// set Unity items 037.this.eventAggregator = eventAgg; 038.this.regionManager = regionmanager; 039.// load our context 040.context = new RecruitingContext(); 041.this._myJobs = new QueryableCollectionView(context.JobPostings); 042.context.Load(context.GetJobPostingsQuery()); 043.// set command events 044.this.AddRecord = new DelegateCommand<object>(this.AddNewRecord); 045.this.EditRecord = new DelegateCommand<object>(this.EditExistingRecord); 046.this.SelectedItemChanged = new DelegateCommand<object>(this.SelectedRecordChanged); 047.SetSubscriptions(); 048.} 049.#region DelegateCommands from View 050.public void AddNewRecord(object obj) 051.{ 052.this.eventAggregator.GetEvent<AddJobEvent>().Publish(true); 053.} 054.public void EditExistingRecord(object obj) 055.{ 056.if (_selectedJob == null) 057.{ 058.this.eventAggregator.GetEvent<NotifyUserEvent>().Publish("No job selected."); 059.} 060.else 061.{ 062.this._myJobs.EditItem(this._selectedJob); 063.this.eventAggregator.GetEvent<EditJobEvent>().Publish(this._selectedJob); 064.} 065.} 066.public void SelectedRecordChanged(object obj) 067.{ 068.if (obj.GetType() == typeof(ActionHistory)) 069.{ 070.// event bubbles up so we don't catch items from the ActionHistory grid 071.} 072.else 073.{ 074.JobPosting job = obj as JobPosting; 075.GrabHistory(job.PostingID); 076.} 077.} 078.#endregion 079.#region Subscription Declaration and Events 080.public void SetSubscriptions() 081.{ 082.EditJobCompleteEvent editComplete = eventAggregator.GetEvent<EditJobCompleteEvent>(); 083.if (editToken != null) 084.editComplete.Unsubscribe(editToken); 085.editToken = editComplete.Subscribe(this.EditCompleteEventHandler); 086.AddJobCompleteEvent addComplete = eventAggregator.GetEvent<AddJobCompleteEvent>(); 087.if (addToken != null) 088.addComplete.Unsubscribe(addToken); 089.addToken = addComplete.Subscribe(this.AddCompleteEventHandler); 090.} 091.public void EditCompleteEventHandler(bool complete) 092.{ 093.if (complete) 094.{ 095.JobPosting thisJob = _myJobs.CurrentEditItem as JobPosting; 096.this._myJobs.CommitEdit(); 097.this.context.SubmitChanges((s) => 098.{ 099.ActionHistory myAction = new ActionHistory(); 100.myAction.PostingID = thisJob.PostingID; 101.myAction.Description = String.Format("Job '{0}' has been edited by {1}", thisJob.JobTitle, "default user"); 102.myAction.TimeStamp = DateTime.Now; 103.eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 104.} 105., null); 106.} 107.else 108.{ 109.this._myJobs.CancelEdit(); 110.} 111.this.MakeMeActive(this.regionManager, "MainRegion", "JobPostingsView"); 112.} 113.public void AddCompleteEventHandler(JobPosting job) 114.{ 115.if (job == null) 116.{ 117.// do nothing, new job add cancelled 118.} 119.else 120.{ 121.this.context.JobPostings.Add(job); 122.this.context.SubmitChanges((s) => 123.{ 124.ActionHistory myAction = new ActionHistory(); 125.myAction.PostingID = job.PostingID; 126.myAction.Description = String.Format("Job '{0}' has been added by {1}", job.JobTitle, "default user"); 127.myAction.TimeStamp = DateTime.Now; 128.eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 129.} 130., null); 131.} 132.this.MakeMeActive(this.regionManager, "MainRegion", "JobPostingsView"); 133.} 134.#endregion 135.public void GrabHistory(int postID) 136.{ 137.context.ActionHistories.Clear(); 138._selectionJobActionHistory = new QueryableCollectionView(context.ActionHistories); 139.context.Load(context.GetHistoryForJobQuery(postID)); 140.} Taking it from the top, we're injecting an Event Aggregator and Region Manager for use down the road and also have the public DelegateCommands (just like in the Menu module). We also grab a reference to our context, which we'll obviously need for data, then set up a few fields with public properties tied to them. We're also setting subscription tokens, which we have not yet seen but I will get into below. The AddNewRecord (50) and EditExistingRecord (54) methods should speak for themselves for functionality, the one thing of note is we're sending events off to the Event Aggregator which some module, somewhere will take care of. Since these aren't entirely relying on one another, the Jobs View doesn't care if anyone is listening, but it will publish AddJobEvent (52), NotifyUserEvent (58) and EditJobEvent (63)regardless. Don't mind the GrabHistory() method so much, that is just grabbing history items (visibly being created in the SubmitChanges callbacks), and adding them to the database. Every action will trigger a history event, so we'll know who modified what and when, just in case. ;) So where are we at? Well, if we click to Add a job, we publish an event, if we edit a job, we publish an event with the selected record (attained through the magic of binding). Where is this all going though? To the Viewmodel, of course! XAML for the AddEditJobView This is pretty straightforward except for one thing, noted below: 001.<Grid x:Name="LayoutRoot" 002.Background="White"> 003.<Grid x:Name="xEditGrid" 004.Margin="10" 005.validationHelper:ValidationScope.Errors="{Binding Errors}"> 006.<Grid.Background> 007.<LinearGradientBrush EndPoint="0.5,1" 008.StartPoint="0.5,0"> 009.<GradientStop Color="#FFC7C7C7" 010.Offset="0" /> 011.<GradientStop Color="#FFF6F3F3" 012.Offset="1" /> 013.</LinearGradientBrush> 014.</Grid.Background> 015.<Grid.RowDefinitions> 016.<RowDefinition Height="40" /> 017.<RowDefinition Height="40" /> 018.<RowDefinition Height="40" /> 019.<RowDefinition Height="100" /> 020.<RowDefinition Height="100" /> 021.<RowDefinition Height="100" /> 022.<RowDefinition Height="40" /> 023.<RowDefinition Height="40" /> 024.<RowDefinition Height="40" /> 025.</Grid.RowDefinitions> 026.<Grid.ColumnDefinitions> 027.<ColumnDefinition Width="150" /> 028.<ColumnDefinition Width="150" /> 029.<ColumnDefinition Width="300" /> 030.<ColumnDefinition Width="100" /> 031.</Grid.ColumnDefinitions> 032. 033.<TextBlock Margin="8" 034.Text="{Binding AddEditString}" 035.TextWrapping="Wrap" 036.Grid.Column="1" 037.Grid.ColumnSpan="2" 038.FontSize="16" /> 039. 040. 041.<TextBlock Margin="8,0,0,0" 042.Style="{StaticResource LabelTxb}" 043.Grid.Row="1" 044.Text="Job Title" 045.VerticalAlignment="Center" /> 046.<TextBox x:Name="xJobTitleTB" 047.Margin="0,8" 048.Grid.Column="1" 049.Grid.Row="1" 050.Text="{Binding activeJob.JobTitle, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 051.Grid.ColumnSpan="2" /> 052.<TextBlock Margin="8,0,0,0" 053.Grid.Row="2" 054.Text="Location" 055.d:LayoutOverrides="Height" 056.VerticalAlignment="Center" /> 057.<TextBox x:Name="xLocationTB" 058.Margin="0,8" 059.Grid.Column="1" 060.Grid.Row="2" 061.Text="{Binding activeJob.Location, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 062.Grid.ColumnSpan="2" /> 063. 064.<TextBlock Margin="8,11,8,0" 065.Grid.Row="3" 066.Text="Description" 067.TextWrapping="Wrap" 068.VerticalAlignment="Top" /> 069. 070.<TextBox x:Name="xDescriptionTB" 071.Height="84" 072.TextWrapping="Wrap" 073.ScrollViewer.VerticalScrollBarVisibility="Auto" 074.Grid.Column="1" 075.Grid.Row="3" 076.Text="{Binding activeJob.Description, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 077.Grid.ColumnSpan="2" /> 078.<TextBlock Margin="8,11,8,0" 079.Grid.Row="4" 080.Text="Requirements" 081.TextWrapping="Wrap" 082.VerticalAlignment="Top" /> 083. 084.<TextBox x:Name="xRequirementsTB" 085.Height="84" 086.TextWrapping="Wrap" 087.ScrollViewer.VerticalScrollBarVisibility="Auto" 088.Grid.Column="1" 089.Grid.Row="4" 090.Text="{Binding activeJob.Requirements, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 091.Grid.ColumnSpan="2" /> 092.<TextBlock Margin="8,11,8,0" 093.Grid.Row="5" 094.Text="Qualifications" 095.TextWrapping="Wrap" 096.VerticalAlignment="Top" /> 097. 098.<TextBox x:Name="xQualificationsTB" 099.Height="84" 100.TextWrapping="Wrap" 101.ScrollViewer.VerticalScrollBarVisibility="Auto" 102.Grid.Column="1" 103.Grid.Row="5" 104.Text="{Binding activeJob.Qualifications, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 105.Grid.ColumnSpan="2" /> 106. 107. 108.<CheckBox x:Name="xResumeRequiredCB" Margin="8,8,8,15" 109.Content="Resume Required" 110.Grid.Row="6" 111.Grid.ColumnSpan="2" 112.IsChecked="{Binding activeJob.NeedsResume, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 113. 114.<CheckBox x:Name="xCoverletterRequiredCB" Margin="8,8,8,15" 115.Content="Cover Letter Required" 116.Grid.Column="2" 117.Grid.Row="6" 118.IsChecked="{Binding activeJob.NeedsCV, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 119. 120.<CheckBox x:Name="xOverviewRequiredCB" Margin="8,8,8,15" 121.Content="Overview Required" 122.Grid.Row="7" 123.Grid.ColumnSpan="2" 124.IsChecked="{Binding activeJob.NeedsOverview, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 125. 126.<CheckBox x:Name="xJobActiveCB" Margin="8,8,8,15" 127.Content="Job is Active" 128.Grid.Column="2" 129.Grid.Row="7" 130.IsChecked="{Binding activeJob.IsActive, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 131. 132. 133. 134.<Button x:Name="xAddEditButton" Margin="8,8,0,10" 135.Content="{Binding AddEditButtonString}" 136.cal:Click.Command="{Binding AddEditCommand}" 137.Grid.Column="2" 138.Grid.Row="8" 139.HorizontalAlignment="Left" 140.Width="125" 141.telerik:StyleManager.Theme="Windows7" /> 142. 143.<Button x:Name="xCancelButton" HorizontalAlignment="Right" 144.Content="Cancel" 145.cal:Click.Command="{Binding CancelCommand}" 146.Margin="0,8,8,10" 147.Width="125" 148.Grid.Column="2" 149.Grid.Row="8" 150.telerik:StyleManager.Theme="Windows7" /> 151.</Grid> 152.</Grid> The 'validationHelper:ValidationScope' line may seem odd. This is a handy little trick for catching current and would-be validation errors when working in this whole setup. This all comes from an approach found on theJoy Of Code blog, although it looks like the story for this will be changing slightly with new advances in SL4/WCF RIA Services, so this section can definitely get an overhaul a little down the road. The code is the fun part of all this, so let us see what's happening under the hood. Viewmodel for the AddEditJobView We are going to see some of the same things happening here, so I'll skip over the repeat info and get right to the good stuff: 001.public class AddEditJobViewModel : ViewModelBase 002.{ 003.private readonly IEventAggregator eventAggregator; 004.private readonly IRegionManager regionManager; 005. 006.public RecruitingContext context; 007. 008.private JobPosting _activeJob; 009.public JobPosting activeJob 010.{ 011.get { return _activeJob; } 012.set 013.{ 014.if (_activeJob != value) 015.{ 016._activeJob = value; 017.NotifyChanged("activeJob"); 018.} 019.} 020.} 021. 022.public bool isNewJob; 023. 024.private string _addEditString; 025.public string AddEditString 026.{ 027.get { return _addEditString; } 028.set 029.{ 030.if (_addEditString != value) 031.{ 032._addEditString = value; 033.NotifyChanged("AddEditString"); 034.} 035.} 036.} 037. 038.private string _addEditButtonString; 039.public string AddEditButtonString 040.{ 041.get { return _addEditButtonString; } 042.set 043.{ 044.if (_addEditButtonString != value) 045.{ 046._addEditButtonString = value; 047.NotifyChanged("AddEditButtonString"); 048.} 049.} 050.} 051. 052.public SubscriptionToken addJobToken = new SubscriptionToken(); 053.public SubscriptionToken editJobToken = new SubscriptionToken(); 054. 055.public DelegateCommand<object> AddEditCommand { get; set; } 056.public DelegateCommand<object> CancelCommand { get; set; } 057. 058.private ObservableCollection<ValidationError> _errors = new ObservableCollection<ValidationError>(); 059.public ObservableCollection<ValidationError> Errors 060.{ 061.get { return _errors; } 062.} 063. 064.private ObservableCollection<ValidationResult> _valResults = new ObservableCollection<ValidationResult>(); 065.public ObservableCollection<ValidationResult> ValResults 066.{ 067.get { return this._valResults; } 068.} 069. 070.public AddEditJobViewModel(IEventAggregator eventAgg, IRegionManager regionmanager) 071.{ 072.// set Unity items 073.this.eventAggregator = eventAgg; 074.this.regionManager = regionmanager; 075. 076.context = new RecruitingContext(); 077. 078.AddEditCommand = new DelegateCommand<object>(this.AddEditJobCommand); 079.CancelCommand = new DelegateCommand<object>(this.CancelAddEditCommand); 080. 081.SetSubscriptions(); 082.} 083. 084.#region Subscription Declaration and Events 085. 086.public void SetSubscriptions() 087.{ 088.AddJobEvent addJob = this.eventAggregator.GetEvent<AddJobEvent>(); 089. 090.if (addJobToken != null) 091.addJob.Unsubscribe(addJobToken); 092. 093.addJobToken = addJob.Subscribe(this.AddJobEventHandler); 094. 095.EditJobEvent editJob = this.eventAggregator.GetEvent<EditJobEvent>(); 096. 097.if (editJobToken != null) 098.editJob.Unsubscribe(editJobToken); 099. 100.editJobToken = editJob.Subscribe(this.EditJobEventHandler); 101.} 102. 103.public void AddJobEventHandler(bool isNew) 104.{ 105.this.activeJob = null; 106.this.activeJob = new JobPosting(); 107.this.activeJob.IsActive = true; // We assume that we want a new job to go up immediately 108.this.isNewJob = true; 109.this.AddEditString = "Add New Job Posting"; 110.this.AddEditButtonString = "Add Job"; 111. 112.MakeMeActive(this.regionManager, "MainRegion", "AddEditJobView"); 113.} 114. 115.public void EditJobEventHandler(JobPosting editJob) 116.{ 117.this.activeJob = null; 118.this.activeJob = editJob; 119.this.isNewJob = false; 120.this.AddEditString = "Edit Job Posting"; 121.this.AddEditButtonString = "Edit Job"; 122. 123.MakeMeActive(this.regionManager, "MainRegion", "AddEditJobView"); 124.} 125. 126.#endregion 127. 128.#region DelegateCommands from View 129. 130.public void AddEditJobCommand(object obj) 131.{ 132.if (this.Errors.Count > 0) 133.{ 134.List<string> errorMessages = new List<string>(); 135. 136.foreach (var valR in this.Errors) 137.{ 138.errorMessages.Add(valR.Exception.Message); 139.} 140. 141.this.eventAggregator.GetEvent<DisplayValidationErrorsEvent>().Publish(errorMessages); 142. 143.} 144.else if (!Validator.TryValidateObject(this.activeJob, new ValidationContext(this.activeJob, null, null), _valResults, true)) 145.{ 146.List<string> errorMessages = new List<string>(); 147. 148.foreach (var valR in this._valResults) 149.{ 150.errorMessages.Add(valR.ErrorMessage); 151.} 152. 153.this._valResults.Clear(); 154. 155.this.eventAggregator.GetEvent<DisplayValidationErrorsEvent>().Publish(errorMessages); 156.} 157.else 158.{ 159.if (this.isNewJob) 160.{ 161.this.eventAggregator.GetEvent<AddJobCompleteEvent>().Publish(this.activeJob); 162.} 163.else 164.{ 165.this.eventAggregator.GetEvent<EditJobCompleteEvent>().Publish(true); 166.} 167.} 168.} 169. 170.public void CancelAddEditCommand(object obj) 171.{ 172.if (this.isNewJob) 173.{ 174.this.eventAggregator.GetEvent<AddJobCompleteEvent>().Publish(null); 175.} 176.else 177.{ 178.this.eventAggregator.GetEvent<EditJobCompleteEvent>().Publish(false); 179.} 180.} 181. 182.#endregion 183.} 184.} We start seeing something new on line 103- the AddJobEventHandler will create a new job and set that to the activeJob item on the ViewModel. When this is all set, the view calls that familiar MakeMeActive method to activate itself. I made a bit of a management call on making views self-activate like this, but I figured it works for one reason. As I create this application, views may not exist that I have in mind, so after a view receives its 'ping' from being subscribed to an event, it prepares whatever it needs to do and then goes active. This way if I don't have 'edit' hooked up, I can click as the day is long on the main view and won't get lost in an empty region. Total personal preference here. :) Everything else should again be pretty straightforward, although I do a bit of validation checking in the AddEditJobCommand, which can either fire off an event back to the main view/viewmodel if everything is a success or sent a list of errors to our notification module, which pops open a RadWindow with the alerts if any exist. As a bonus side note, here's what my WCF RIA Services metadata looks like for handling all of the validation: private JobPostingMetadata() { } [StringLength(2500, ErrorMessage = "Description should be more than one and less than 2500 characters.", MinimumLength = 1)] [Required(ErrorMessage = "Description is required.")] public string Description; [Required(ErrorMessage="Active Status is Required")] public bool IsActive; [StringLength(100, ErrorMessage = "Posting title must be more than 3 but less than 100 characters.", MinimumLength = 3)] [Required(ErrorMessage = "Job Title is required.")] public bool JobTitle; [Required] public string Location; public bool NeedsCV; public bool NeedsOverview; public bool NeedsResume; public int PostingID; [Required(ErrorMessage="Qualifications are required.")] [StringLength(2500, ErrorMessage="Qualifications should be more than one and less than 2500 characters.", MinimumLength=1)] public string Qualifications; [StringLength(2500, ErrorMessage = "Requirements should be more than one and less than 2500 characters.", MinimumLength = 1)] [Required(ErrorMessage="Requirements are required.")] public string Requirements; The RecruitCB Alternative See all that Xaml I pasted above? Those are now two pieces sitting in the JobsView.xaml file now. The only real difference is that the xEditGrid now sits in the same place as xJobsGrid, with visibility swapping out between the two for a quick switch. I also took out all the cal: and command: command references and replaced Button events with clicks and the Grid selection command replaced with a SelectedItemChanged event. Also, at the bottom of the xEditGrid after the last button, I add a ValidationSummary (with Visibility=Collapsed) to catch any errors that are popping up. Simple as can be, and leads to this being the single code-behind file: 001.public partial class JobsView : UserControl 002.{ 003.public RecruitingContext context; 004.public JobPosting activeJob; 005.public bool isNew; 006.private ObservableCollection<ValidationResult> _valResults = new ObservableCollection<ValidationResult>(); 007.public ObservableCollection<ValidationResult> ValResults 008.{ 009.get { return this._valResults; } 010.} 011.public JobsView() 012.{ 013.InitializeComponent(); 014.this.Loaded += new RoutedEventHandler(JobsView_Loaded); 015.} 016.void JobsView_Loaded(object sender, RoutedEventArgs e) 017.{ 018.context = new RecruitingContext(); 019.xJobsGrid.ItemsSource = context.JobPostings; 020.context.Load(context.GetJobPostingsQuery()); 021.} 022.private void xAddRecordButton_Click(object sender, RoutedEventArgs e) 023.{ 024.activeJob = new JobPosting(); 025.isNew = true; 026.xAddEditTitle.Text = "Add a Job Posting"; 027.xAddEditButton.Content = "Add"; 028.xEditGrid.DataContext = activeJob; 029.HideJobsGrid(); 030.} 031.private void xEditRecordButton_Click(object sender, RoutedEventArgs e) 032.{ 033.activeJob = xJobsGrid.SelectedItem as JobPosting; 034.isNew = false; 035.xAddEditTitle.Text = "Edit a Job Posting"; 036.xAddEditButton.Content = "Edit"; 037.xEditGrid.DataContext = activeJob; 038.HideJobsGrid(); 039.} 040.private void xAddEditButton_Click(object sender, RoutedEventArgs e) 041.{ 042.if (!Validator.TryValidateObject(this.activeJob, new ValidationContext(this.activeJob, null, null), _valResults, true)) 043.{ 044.List<string> errorMessages = new List<string>(); 045.foreach (var valR in this._valResults) 046.{ 047.errorMessages.Add(valR.ErrorMessage); 048.} 049.this._valResults.Clear(); 050.ShowErrors(errorMessages); 051.} 052.else if (xSummary.Errors.Count > 0) 053.{ 054.List<string> errorMessages = new List<string>(); 055.foreach (var err in xSummary.Errors) 056.{ 057.errorMessages.Add(err.Message); 058.} 059.ShowErrors(errorMessages); 060.} 061.else 062.{ 063.if (this.isNew) 064.{ 065.context.JobPostings.Add(activeJob); 066.context.SubmitChanges((s) => 067.{ 068.ActionHistory thisAction = new ActionHistory(); 069.thisAction.PostingID = activeJob.PostingID; 070.thisAction.Description = String.Format("Job '{0}' has been edited by {1}", activeJob.JobTitle, "default user"); 071.thisAction.TimeStamp = DateTime.Now; 072.context.ActionHistories.Add(thisAction); 073.context.SubmitChanges(); 074.}, null); 075.} 076.else 077.{ 078.context.SubmitChanges((s) => 079.{ 080.ActionHistory thisAction = new ActionHistory(); 081.thisAction.PostingID = activeJob.PostingID; 082.thisAction.Description = String.Format("Job '{0}' has been added by {1}", activeJob.JobTitle, "default user"); 083.thisAction.TimeStamp = DateTime.Now; 084.context.ActionHistories.Add(thisAction); 085.context.SubmitChanges(); 086.}, null); 087.} 088.ShowJobsGrid(); 089.} 090.} 091.private void xCancelButton_Click(object sender, RoutedEventArgs e) 092.{ 093.ShowJobsGrid(); 094.} 095.private void ShowJobsGrid() 096.{ 097.xAddEditRecordButtonPanel.Visibility = Visibility.Visible; 098.xEditGrid.Visibility = Visibility.Collapsed; 099.xJobsGrid.Visibility = Visibility.Visible; 100.} 101.private void HideJobsGrid() 102.{ 103.xAddEditRecordButtonPanel.Visibility = Visibility.Collapsed; 104.xJobsGrid.Visibility = Visibility.Collapsed; 105.xEditGrid.Visibility = Visibility.Visible; 106.} 107.private void ShowErrors(List<string> errorList) 108.{ 109.string nm = "Errors received: \n"; 110.foreach (string anerror in errorList) 111.nm += anerror + "\n"; 112.RadWindow.Alert(nm); 113.} 114.} The first 39 lines should be pretty familiar, not doing anything too unorthodox to get this up and running. Once we hit the xAddEditButton_Click on line 40, we're still doing pretty much the same things except instead of checking the ValidationHelper errors, we both run a check on the current activeJob object as well as check the ValidationSummary errors list. Once that is set, we again use the callback of context.SubmitChanges (lines 68 and 78) to create an ActionHistory which we will use to track these items down the line. That's all? Essentially... yes. If you look back through this post, most of the code and adventures we have taken were just to get things working in the MVVM/Prism setup. Since I have the whole 'module' self-contained in a single JobView+code-behind setup, I don't have to worry about things like sending events off into space for someone to pick up, communicating through an Infrastructure project, or even re-inventing events to be used with attached behaviors. Everything just kinda works, and again with much less code. Here's a picture of the MVVM and Code-behind versions on the Jobs and AddEdit views, but since the functionality is the same in both apps you still cannot tell them apart (for two-strike): Looking ahead, the Applicants module is effectively the same thing as the Jobs module, so most of the code is being cut-and-pasted back and forth with minor tweaks here and there. So that one is being taken care of by me behind the scenes. Next time, we get into a new world of fun- the interview scheduling module, which will pull from available jobs and applicants for each interview being scheduled, tying everything together with RadScheduler to the rescue. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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Problem rendering VBO

- by Onno

I'm developing a game engine using OpenTK. I'm trying to get to grips with the use of VBO's. I've run into some trouble because somehow it doesn't render correctly. Thus far I've used immediate mode to render a test object, a test cube with a texture. namespace SharpEngine.Utility.Mesh { using System; using System.Collections.Generic; using OpenTK; using OpenTK.Graphics; using OpenTK.Graphics.OpenGL; using SharpEngine.Utility; using System.Drawing; public class ImmediateFaceBasedCube : IMesh { private IList<Face> faces = new List<Face>(); public ImmediateFaceBasedCube() { IList<Vector3> allVertices = new List<Vector3>(); //rechtsbovenvoor allVertices.Add(new Vector3(1.0f, 1.0f, 1.0f)); //0 //rechtsbovenachter allVertices.Add(new Vector3(1.0f, 1.0f, -1.0f)); //1 //linksbovenachter allVertices.Add(new Vector3(-1.0f, 1.0f, -1.0f)); //2 //linksbovenvoor allVertices.Add(new Vector3(-1.0f, 1.0f, 1.0f)); //3 //rechtsondervoor allVertices.Add(new Vector3(1.0f, -1.0f, 1.0f)); //4 //rechtsonderachter allVertices.Add(new Vector3(1.0f, -1.0f, -1.0f)); //5 //linksonderachter allVertices.Add(new Vector3(-1.0f, -1.0f, -1.0f)); //6 //linksondervoor allVertices.Add(new Vector3(-1.0f, -1.0f, 1.0f)); //7 IList<Vector2> textureCoordinates = new List<Vector2>(); textureCoordinates.Add(new Vector2(0, 0)); //AA - 0 textureCoordinates.Add(new Vector2(0, 0.3333333f)); //AB - 1 textureCoordinates.Add(new Vector2(0, 0.6666666f)); //AC - 2 textureCoordinates.Add(new Vector2(0, 1)); //AD - 3 textureCoordinates.Add(new Vector2(0.3333333f, 0)); //BA - 4 textureCoordinates.Add(new Vector2(0.3333333f, 0.3333333f)); //BB - 5 textureCoordinates.Add(new Vector2(0.3333333f, 0.6666666f)); //BC - 6 textureCoordinates.Add(new Vector2(0.3333333f, 1)); //BD - 7 textureCoordinates.Add(new Vector2(0.6666666f, 0)); //CA - 8 textureCoordinates.Add(new Vector2(0.6666666f, 0.3333333f)); //CB - 9 textureCoordinates.Add(new Vector2(0.6666666f, 0.6666666f)); //CC -10 textureCoordinates.Add(new Vector2(0.6666666f, 1)); //CD -11 textureCoordinates.Add(new Vector2(1, 0)); //DA -12 textureCoordinates.Add(new Vector2(1, 0.3333333f)); //DB -13 textureCoordinates.Add(new Vector2(1, 0.6666666f)); //DC -14 textureCoordinates.Add(new Vector2(1, 1)); //DD -15 Vector3 copy1 = new Vector3(-2.0f, -2.5f, -3.5f); IList<Vector3> normals = new List<Vector3>(); normals.Add(new Vector3(0, 1.0f, 0)); //0 normals.Add(new Vector3(0, 0, 1.0f)); //1 normals.Add(new Vector3(1.0f, 0, 0)); //2 normals.Add(new Vector3(0, 0, -1.0f)); //3 normals.Add(new Vector3(-1.0f, 0, 0)); //4 normals.Add(new Vector3(0, -1.0f, 0)); //5 //todo: move vertex normal and texture data to datastructure //todo: VBO based rendering //top face //1 IList<VertexData> verticesT1 = new List<VertexData>(); VertexData T1a = new VertexData(); T1a.Normal = normals[0]; T1a.TexCoord = textureCoordinates[5]; T1a.Position = allVertices[3]; verticesT1.Add(T1a); VertexData T1b = new VertexData(); T1b.Normal = normals[0]; T1b.TexCoord = textureCoordinates[9]; T1b.Position = allVertices[0]; verticesT1.Add(T1b); VertexData T1c = new VertexData(); T1c.Normal = normals[0]; T1c.TexCoord = textureCoordinates[10]; T1c.Position = allVertices[1]; verticesT1.Add(T1c); Face F1 = new Face(verticesT1); faces.Add(F1); //2 IList<VertexData> verticesT2 = new List<VertexData>(); VertexData T2a = new VertexData(); T2a.Normal = normals[0]; T2a.TexCoord = textureCoordinates[10]; T2a.Position = allVertices[1]; verticesT2.Add(T2a); VertexData T2b = new VertexData(); T2b.Normal = normals[0]; T2b.TexCoord = textureCoordinates[6]; T2b.Position = allVertices[2]; verticesT2.Add(T2b); VertexData T2c = new VertexData(); T2c.Normal = normals[0]; T2c.TexCoord = textureCoordinates[5]; T2c.Position = allVertices[3]; verticesT2.Add(T2c); Face F2 = new Face(verticesT2); faces.Add(F2); //front face //3 IList<VertexData> verticesT3 = new List<VertexData>(); VertexData T3a = new VertexData(); T3a.Normal = normals[1]; T3a.TexCoord = textureCoordinates[1]; T3a.Position = allVertices[3]; verticesT3.Add(T3a); VertexData T3b = new VertexData(); T3b.Normal = normals[1]; T3b.TexCoord = textureCoordinates[0]; T3b.Position = allVertices[7]; verticesT3.Add(T3b); VertexData T3c = new VertexData(); T3c.Normal = normals[1]; T3c.TexCoord = textureCoordinates[5]; T3c.Position = allVertices[0]; verticesT3.Add(T3c); Face F3 = new Face(verticesT3); faces.Add(F3); //4 IList<VertexData> verticesT4 = new List<VertexData>(); VertexData T4a = new VertexData(); T4a.Normal = normals[1]; T4a.TexCoord = textureCoordinates[5]; T4a.Position = allVertices[0]; verticesT4.Add(T4a); VertexData T4b = new VertexData(); T4b.Normal = normals[1]; T4b.TexCoord = textureCoordinates[0]; T4b.Position = allVertices[7]; verticesT4.Add(T4b); VertexData T4c = new VertexData(); T4c.Normal = normals[1]; T4c.TexCoord = textureCoordinates[4]; T4c.Position = allVertices[4]; verticesT4.Add(T4c); Face F4 = new Face(verticesT4); faces.Add(F4); //right face //5 IList<VertexData> verticesT5 = new List<VertexData>(); VertexData T5a = new VertexData(); T5a.Normal = normals[2]; T5a.TexCoord = textureCoordinates[2]; T5a.Position = allVertices[0]; verticesT5.Add(T5a); VertexData T5b = new VertexData(); T5b.Normal = normals[2]; T5b.TexCoord = textureCoordinates[1]; T5b.Position = allVertices[4]; verticesT5.Add(T5b); VertexData T5c = new VertexData(); T5c.Normal = normals[2]; T5c.TexCoord = textureCoordinates[6]; T5c.Position = allVertices[1]; verticesT5.Add(T5c); Face F5 = new Face(verticesT5); faces.Add(F5); //6 IList<VertexData> verticesT6 = new List<VertexData>(); VertexData T6a = new VertexData(); T6a.Normal = normals[2]; T6a.TexCoord = textureCoordinates[1]; T6a.Position = allVertices[4]; verticesT6.Add(T6a); VertexData T6b = new VertexData(); T6b.Normal = normals[2]; T6b.TexCoord = textureCoordinates[5]; T6b.Position = allVertices[5]; verticesT6.Add(T6b); VertexData T6c = new VertexData(); T6c.Normal = normals[2]; T6c.TexCoord = textureCoordinates[6]; T6c.Position = allVertices[1]; verticesT6.Add(T6c); Face F6 = new Face(verticesT6); faces.Add(F6); //back face //7 IList<VertexData> verticesT7 = new List<VertexData>(); VertexData T7a = new VertexData(); T7a.Normal = normals[3]; T7a.TexCoord = textureCoordinates[4]; T7a.Position = allVertices[5]; verticesT7.Add(T7a); VertexData T7b = new VertexData(); T7b.Normal = normals[3]; T7b.TexCoord = textureCoordinates[9]; T7b.Position = allVertices[2]; verticesT7.Add(T7b); VertexData T7c = new VertexData(); T7c.Normal = normals[3]; T7c.TexCoord = textureCoordinates[5]; T7c.Position = allVertices[1]; verticesT7.Add(T7c); Face F7 = new Face(verticesT7); faces.Add(F7); //8 IList<VertexData> verticesT8 = new List<VertexData>(); VertexData T8a = new VertexData(); T8a.Normal = normals[3]; T8a.TexCoord = textureCoordinates[9]; T8a.Position = allVertices[2]; verticesT8.Add(T8a); VertexData T8b = new VertexData(); T8b.Normal = normals[3]; T8b.TexCoord = textureCoordinates[4]; T8b.Position = allVertices[5]; verticesT8.Add(T8b); VertexData T8c = new VertexData(); T8c.Normal = normals[3]; T8c.TexCoord = textureCoordinates[8]; T8c.Position = allVertices[6]; verticesT8.Add(T8c); Face F8 = new Face(verticesT8); faces.Add(F8); //left face //9 IList<VertexData> verticesT9 = new List<VertexData>(); VertexData T9a = new VertexData(); T9a.Normal = normals[4]; T9a.TexCoord = textureCoordinates[8]; T9a.Position = allVertices[6]; verticesT9.Add(T9a); VertexData T9b = new VertexData(); T9b.Normal = normals[4]; T9b.TexCoord = textureCoordinates[13]; T9b.Position = allVertices[3]; verticesT9.Add(T9b); VertexData T9c = new VertexData(); T9c.Normal = normals[4]; T9c.TexCoord = textureCoordinates[9]; T9c.Position = allVertices[2]; verticesT9.Add(T9c); Face F9 = new Face(verticesT9); faces.Add(F9); //10 IList<VertexData> verticesT10 = new List<VertexData>(); VertexData T10a = new VertexData(); T10a.Normal = normals[4]; T10a.TexCoord = textureCoordinates[8]; T10a.Position = allVertices[6]; verticesT10.Add(T10a); VertexData T10b = new VertexData(); T10b.Normal = normals[4]; T10b.TexCoord = textureCoordinates[12]; T10b.Position = allVertices[7]; verticesT10.Add(T10b); VertexData T10c = new VertexData(); T10c.Normal = normals[4]; T10c.TexCoord = textureCoordinates[13]; T10c.Position = allVertices[3]; verticesT10.Add(T10c); Face F10 = new Face(verticesT10); faces.Add(F10); //bottom face //11 IList<VertexData> verticesT11 = new List<VertexData>(); VertexData T11a = new VertexData(); T11a.Normal = normals[5]; T11a.TexCoord = textureCoordinates[10]; T11a.Position = allVertices[7]; verticesT11.Add(T11a); VertexData T11b = new VertexData(); T11b.Normal = normals[5]; T11b.TexCoord = textureCoordinates[9]; T11b.Position = allVertices[6]; verticesT11.Add(T11b); VertexData T11c = new VertexData(); T11c.Normal = normals[5]; T11c.TexCoord = textureCoordinates[14]; T11c.Position = allVertices[4]; verticesT11.Add(T11c); Face F11 = new Face(verticesT11); faces.Add(F11); //12 IList<VertexData> verticesT12 = new List<VertexData>(); VertexData T12a = new VertexData(); T12a.Normal = normals[5]; T12a.TexCoord = textureCoordinates[13]; T12a.Position = allVertices[5]; verticesT12.Add(T12a); VertexData T12b = new VertexData(); T12b.Normal = normals[5]; T12b.TexCoord = textureCoordinates[14]; T12b.Position = allVertices[4]; verticesT12.Add(T12b); VertexData T12c = new VertexData(); T12c.Normal = normals[5]; T12c.TexCoord = textureCoordinates[9]; T12c.Position = allVertices[6]; verticesT12.Add(T12c); Face F12 = new Face(verticesT12); faces.Add(F12); } public void draw() { GL.Begin(BeginMode.Triangles); foreach (Face face in faces) { foreach (VertexData datapoint in face.verticesWithTexCoords) { GL.Normal3(datapoint.Normal); GL.TexCoord2(datapoint.TexCoord); GL.Vertex3(datapoint.Position); } } GL.End(); } } } Gets me this very nice picture: The immediate mode cube renders nicely and taught me a bit on how to use OpenGL, but VBO's are the way to go. Since I read on the OpenTK forums that OpenTK has problems doing VA's or DL's, I decided to skip using those. Now, I've tried to change this cube to a VBO by using the same vertex, normal and tc collections, and making float arrays from them by using the coordinates in combination with uint arrays which contain the index numbers from the immediate cube. (see the private functions at end of the code sample) Somehow this only renders two triangles namespace SharpEngine.Utility.Mesh { using System; using System.Collections.Generic; using OpenTK; using OpenTK.Graphics; using OpenTK.Graphics.OpenGL; using SharpEngine.Utility; using System.Drawing; public class VBOFaceBasedCube : IMesh { private int VerticesVBOID; private int VerticesVBOStride; private int VertexCount; private int ELementBufferObjectID; private int textureCoordinateVBOID; private int textureCoordinateVBOStride; //private int textureCoordinateArraySize; private int normalVBOID; private int normalVBOStride; public VBOFaceBasedCube() { IList<Vector3> allVertices = new List<Vector3>(); //rechtsbovenvoor allVertices.Add(new Vector3(1.0f, 1.0f, 1.0f)); //0 //rechtsbovenachter allVertices.Add(new Vector3(1.0f, 1.0f, -1.0f)); //1 //linksbovenachter allVertices.Add(new Vector3(-1.0f, 1.0f, -1.0f)); //2 //linksbovenvoor allVertices.Add(new Vector3(-1.0f, 1.0f, 1.0f)); //3 //rechtsondervoor allVertices.Add(new Vector3(1.0f, -1.0f, 1.0f)); //4 //rechtsonderachter allVertices.Add(new Vector3(1.0f, -1.0f, -1.0f)); //5 //linksonderachter allVertices.Add(new Vector3(-1.0f, -1.0f, -1.0f)); //6 //linksondervoor allVertices.Add(new Vector3(-1.0f, -1.0f, 1.0f)); //7 IList<Vector2> textureCoordinates = new List<Vector2>(); textureCoordinates.Add(new Vector2(0, 0)); //AA - 0 textureCoordinates.Add(new Vector2(0, 0.3333333f)); //AB - 1 textureCoordinates.Add(new Vector2(0, 0.6666666f)); //AC - 2 textureCoordinates.Add(new Vector2(0, 1)); //AD - 3 textureCoordinates.Add(new Vector2(0.3333333f, 0)); //BA - 4 textureCoordinates.Add(new Vector2(0.3333333f, 0.3333333f)); //BB - 5 textureCoordinates.Add(new Vector2(0.3333333f, 0.6666666f)); //BC - 6 textureCoordinates.Add(new Vector2(0.3333333f, 1)); //BD - 7 textureCoordinates.Add(new Vector2(0.6666666f, 0)); //CA - 8 textureCoordinates.Add(new Vector2(0.6666666f, 0.3333333f)); //CB - 9 textureCoordinates.Add(new Vector2(0.6666666f, 0.6666666f)); //CC -10 textureCoordinates.Add(new Vector2(0.6666666f, 1)); //CD -11 textureCoordinates.Add(new Vector2(1, 0)); //DA -12 textureCoordinates.Add(new Vector2(1, 0.3333333f)); //DB -13 textureCoordinates.Add(new Vector2(1, 0.6666666f)); //DC -14 textureCoordinates.Add(new Vector2(1, 1)); //DD -15 Vector3 copy1 = new Vector3(-2.0f, -2.5f, -3.5f); IList<Vector3> normals = new List<Vector3>(); normals.Add(new Vector3(0, 1.0f, 0)); //0 normals.Add(new Vector3(0, 0, 1.0f)); //1 normals.Add(new Vector3(1.0f, 0, 0)); //2 normals.Add(new Vector3(0, 0, -1.0f)); //3 normals.Add(new Vector3(-1.0f, 0, 0)); //4 normals.Add(new Vector3(0, -1.0f, 0)); //5 //todo: VBO based rendering uint[] vertexElements = { 3,0,1, //01 1,2,3, //02 3,7,0, //03 0,7,4, //04 0,4,1, //05 4,5,1, //06 5,2,1, //07 2,5,6, //08 6,3,2, //09 6,7,5, //10 7,6,4, //11 5,4,6 //12 }; VertexCount = vertexElements.Length; IList<uint> vertexElementList = new List<uint>(vertexElements); uint[] normalElements = { 0,0,0, 0,0,0, 1,1,1, 1,1,1, 2,2,2, 2,2,2, 3,3,3, 3,3,3, 4,4,4, 4,4,4, 5,5,5, 5,5,5 }; IList<uint> normalElementList = new List<uint>(normalElements); uint[] textureIndexArray = { 5,9,10, 10,6,5, 1,0,5, 5,0,4, 2,1,6, 1,5,6, 4,9,5, 9,4,8, 8,13,9, 8,12,13, 10,9,14, 13,14,9 }; //textureCoordinateArraySize = textureIndexArray.Length; IList<uint> textureIndexList = new List<uint>(textureIndexArray); LoadVBO(allVertices, normals, textureCoordinates, vertexElements, normalElementList, textureIndexList); } public void draw() { //bind vertices //bind elements //bind normals //bind texture coordinates GL.EnableClientState(ArrayCap.VertexArray); GL.EnableClientState(ArrayCap.NormalArray); GL.EnableClientState(ArrayCap.TextureCoordArray); GL.BindBuffer(BufferTarget.ArrayBuffer, VerticesVBOID); GL.VertexPointer(3, VertexPointerType.Float, VerticesVBOStride, 0); GL.BindBuffer(BufferTarget.ArrayBuffer, normalVBOID); GL.NormalPointer(NormalPointerType.Float, normalVBOStride, 0); GL.BindBuffer(BufferTarget.ArrayBuffer, textureCoordinateVBOID); GL.TexCoordPointer(2, TexCoordPointerType.Float, textureCoordinateVBOStride, 0); GL.BindBuffer(BufferTarget.ElementArrayBuffer, ELementBufferObjectID); GL.DrawElements(BeginMode.Polygon, VertexCount, DrawElementsType.UnsignedShort, 0); } //loads a static VBO void LoadVBO(IList<Vector3> vertices, IList<Vector3> normals, IList<Vector2> texcoords, uint[] elements, IList<uint> normalIndices, IList<uint> texCoordIndices) { int size; //todo // To create a VBO: // 1) Generate the buffer handles for the vertex and element buffers. // 2) Bind the vertex buffer handle and upload your vertex data. Check that the buffer was uploaded correctly. // 3) Bind the element buffer handle and upload your element data. Check that the buffer was uploaded correctly. float[] verticesArray = convertVector3fListToFloatArray(vertices); float[] normalsArray = createFloatArrayFromListOfVector3ElementsAndIndices(normals, normalIndices); float[] textureCoordinateArray = createFloatArrayFromListOfVector2ElementsAndIndices(texcoords, texCoordIndices); GL.GenBuffers(1, out VerticesVBOID); GL.BindBuffer(BufferTarget.ArrayBuffer, VerticesVBOID); Console.WriteLine("load 1 - vertices"); VerticesVBOStride = BlittableValueType.StrideOf(verticesArray); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(verticesArray.Length * sizeof(float)), verticesArray, BufferUsageHint.StaticDraw); GL.GetBufferParameter(BufferTarget.ArrayBuffer, BufferParameterName.BufferSize, out size); if (verticesArray.Length * BlittableValueType.StrideOf(verticesArray) != size) { throw new ApplicationException("Vertex data not uploaded correctly"); } else { Console.WriteLine("load 1 finished ok"); size = 0; } Console.WriteLine("load 2 - elements"); GL.GenBuffers(1, out ELementBufferObjectID); GL.BindBuffer(BufferTarget.ElementArrayBuffer, ELementBufferObjectID); GL.BufferData(BufferTarget.ElementArrayBuffer, (IntPtr)(elements.Length * sizeof(uint)), elements, BufferUsageHint.StaticDraw); GL.GetBufferParameter(BufferTarget.ElementArrayBuffer, BufferParameterName.BufferSize, out size); if (elements.Length * sizeof(uint) != size) { throw new ApplicationException("Element data not uploaded correctly"); } else { size = 0; Console.WriteLine("load 2 finished ok"); } GL.GenBuffers(1, out normalVBOID); GL.BindBuffer(BufferTarget.ArrayBuffer, normalVBOID); Console.WriteLine("load 3 - normals"); normalVBOStride = BlittableValueType.StrideOf(normalsArray); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(normalsArray.Length * sizeof(float)), normalsArray, BufferUsageHint.StaticDraw); GL.GetBufferParameter(BufferTarget.ArrayBuffer, BufferParameterName.BufferSize, out size); Console.WriteLine("load 3 - pre check"); if (normalsArray.Length * BlittableValueType.StrideOf(normalsArray) != size) { throw new ApplicationException("Normal data not uploaded correctly"); } else { Console.WriteLine("load 3 finished ok"); size = 0; } GL.GenBuffers(1, out textureCoordinateVBOID); GL.BindBuffer(BufferTarget.ArrayBuffer, textureCoordinateVBOID); Console.WriteLine("load 4- texture coordinates"); textureCoordinateVBOStride = BlittableValueType.StrideOf(textureCoordinateArray); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(textureCoordinateArray.Length * textureCoordinateVBOStride), textureCoordinateArray, BufferUsageHint.StaticDraw); GL.GetBufferParameter(BufferTarget.ArrayBuffer, BufferParameterName.BufferSize, out size); if (textureCoordinateArray.Length * BlittableValueType.StrideOf(textureCoordinateArray) != size) { throw new ApplicationException("texture coordinate data not uploaded correctly"); } else { Console.WriteLine("load 3 finished ok"); size = 0; } } //used to convert vertex arrayss for use with VBO's private float[] convertVector3fListToFloatArray(IList<Vector3> input) { int arrayElementCount = input.Count * 3; float[] output = new float[arrayElementCount]; int fillCount = 0; foreach (Vector3 v in input) { output[fillCount] = v.X; output[fillCount + 1] = v.Y; output[fillCount + 2] = v.Z; fillCount += 3; } return output; } //used for converting texture coordinate arrays for use with VBO's private float[] convertVector2List_to_floatArray(IList<Vector2> input) { int arrayElementCount = input.Count * 2; float[] output = new float[arrayElementCount]; int fillCount = 0; foreach (Vector2 v in input) { output[fillCount] = v.X; output[fillCount + 1] = v.Y; fillCount += 2; } return output; } //used to create an array of floats from private float[] createFloatArrayFromListOfVector3ElementsAndIndices(IList<Vector3> inputVectors, IList<uint> indices) { int arrayElementCount = inputVectors.Count * indices.Count * 3; float[] output = new float[arrayElementCount]; int fillCount = 0; foreach (int i in indices) { output[fillCount] = inputVectors[i].X; output[fillCount + 1] = inputVectors[i].Y; output[fillCount + 2] = inputVectors[i].Z; fillCount += 3; } return output; } private float[] createFloatArrayFromListOfVector2ElementsAndIndices(IList<Vector2> inputVectors, IList<uint> indices) { int arrayElementCount = inputVectors.Count * indices.Count * 2; float[] output = new float[arrayElementCount]; int fillCount = 0; foreach (int i in indices) { output[fillCount] = inputVectors[i].X; output[fillCount + 1] = inputVectors[i].Y; fillCount += 2; } return output; } } } This code will only render two triangles and they're nothing like I had in mind: I've done some searching. In some other questions I read that, if I did something wrong, I'd get no rendering at all. Clearly, something gets sent to the GFX card, but it might be that I'm not sending the right data. I've tried altering the sequence in which the triangles are rendered by swapping some of the index numbers in the vert, tc and normal index arrays, but this doesn't seem to be of any effect. I'm slightly lost here. What am I doing wrong here?

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value types in the vm

- by john.rose

value types in the vm p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} p.p2 {margin: 0.0px 0.0px 14.0px 0.0px; font: 14.0px Times} p.p3 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times} p.p4 {margin: 0.0px 0.0px 15.0px 0.0px; font: 14.0px Times} p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier} p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier; min-height: 17.0px} p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p8 {margin: 0.0px 0.0px 0.0px 36.0px; text-indent: -36.0px; font: 14.0px Times; min-height: 18.0px} p.p9 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p10 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; color: #000000} li.li1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} li.li7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} span.s1 {font: 14.0px Courier} span.s2 {color: #000000} span.s3 {font: 14.0px Courier; color: #000000} ol.ol1 {list-style-type: decimal} Or, enduring values for a changing world. Introduction A value type is a data type which, generally speaking, is designed for being passed by value in and out of methods, and stored by value in data structures. The only value types which the Java language directly supports are the eight primitive types. Java indirectly and approximately supports value types, if they are implemented in terms of classes. For example, both Integer and String may be viewed as value types, especially if their usage is restricted to avoid operations appropriate to Object. In this note, we propose a definition of value types in terms of a design pattern for Java classes, accompanied by a set of usage restrictions. We also sketch the relation of such value types to tuple types (which are a JVM-level notion), and point out JVM optimizations that can apply to value types. This note is a thought experiment to extend the JVM’s performance model in support of value types. The demonstration has two phases. Initially the extension can simply use design patterns, within the current bytecode architecture, and in today’s Java language. But if the performance model is to be realized in practice, it will probably require new JVM bytecode features, changes to the Java language, or both. We will look at a few possibilities for these new features. An Axiom of Value In the context of the JVM, a value type is a data type equipped with construction, assignment, and equality operations, and a set of typed components, such that, whenever two variables of the value type produce equal corresponding values for their components, the values of the two variables cannot be distinguished by any JVM operation. Here are some corollaries: A value type is immutable, since otherwise a copy could be constructed and the original could be modified in one of its components, allowing the copies to be distinguished. Changing the component of a value type requires construction of a new value. The equals and hashCode operations are strictly component-wise. If a value type is represented by a JVM reference, that reference cannot be successfully synchronized on, and cannot be usefully compared for reference equality. A value type can be viewed in terms of what it doesn’t do. We can say that a value type omits all value-unsafe operations, which could violate the constraints on value types. These operations, which are ordinarily allowed for Java object types, are pointer equality comparison (the acmp instruction), synchronization (the monitor instructions), all the wait and notify methods of class Object, and non-trivial finalize methods. The clone method is also value-unsafe, although for value types it could be treated as the identity function. Finally, and most importantly, any side effect on an object (however visible) also counts as an value-unsafe operation. A value type may have methods, but such methods must not change the components of the value. It is reasonable and useful to define methods like toString, equals, and hashCode on value types, and also methods which are specifically valuable to users of the value type. Representations of Value Value types have two natural representations in the JVM, unboxed and boxed. An unboxed value consists of the components, as simple variables. For example, the complex number x=(1+2i), in rectangular coordinate form, may be represented in unboxed form by the following pair of variables: /*Complex x = Complex.valueOf(1.0, 2.0):*/ double x_re = 1.0, x_im = 2.0; These variables might be locals, parameters, or fields. Their association as components of a single value is not defined to the JVM. Here is a sample computation which computes the norm of the difference between two complex numbers: double distance(/*Complex x:*/ double x_re, double x_im, /*Complex y:*/ double y_re, double y_im) { /*Complex z = x.minus(y):*/ double z_re = x_re - y_re, z_im = x_im - y_im; /*return z.abs():*/ return Math.sqrt(z_re*z_re + z_im*z_im); } A boxed representation groups component values under a single object reference. The reference is to a ‘wrapper class’ that carries the component values in its fields. (A primitive type can naturally be equated with a trivial value type with just one component of that type. In that view, the wrapper class Integer can serve as a boxed representation of value type int.) The unboxed representation of complex numbers is practical for many uses, but it fails to cover several major use cases: return values, array elements, and generic APIs. The two components of a complex number cannot be directly returned from a Java function, since Java does not support multiple return values. The same story applies to array elements: Java has no ’array of structs’ feature. (Double-length arrays are a possible workaround for complex numbers, but not for value types with heterogeneous components.) By generic APIs I mean both those which use generic types, like Arrays.asList and those which have special case support for primitive types, like String.valueOf and PrintStream.println. Those APIs do not support unboxed values, and offer some problems to boxed values. Any ’real’ JVM type should have a story for returns, arrays, and API interoperability. The basic problem here is that value types fall between primitive types and object types. Value types are clearly more complex than primitive types, and object types are slightly too complicated. Objects are a little bit dangerous to use as value carriers, since object references can be compared for pointer equality, and can be synchronized on. Also, as many Java programmers have observed, there is often a performance cost to using wrapper objects, even on modern JVMs. Even so, wrapper classes are a good starting point for talking about value types. If there were a set of structural rules and restrictions which would prevent value-unsafe operations on value types, wrapper classes would provide a good notation for defining value types. This note attempts to define such rules and restrictions. Let’s Start Coding Now it is time to look at some real code. Here is a definition, written in Java, of a complex number value type. @ValueSafe public final class Complex implements java.io.Serializable { // immutable component structure: public final double re, im; private Complex(double re, double im) { this.re = re; this.im = im; } // interoperability methods: public String toString() { return "Complex("+re+","+im+")"; } public List<Double> asList() { return Arrays.asList(re, im); } public boolean equals(Complex c) { return re == c.re && im == c.im; } public boolean equals(@ValueSafe Object x) { return x instanceof Complex && equals((Complex) x); } public int hashCode() { return 31*Double.valueOf(re).hashCode() + Double.valueOf(im).hashCode(); } // factory methods: public static Complex valueOf(double re, double im) { return new Complex(re, im); } public Complex changeRe(double re2) { return valueOf(re2, im); } public Complex changeIm(double im2) { return valueOf(re, im2); } public static Complex cast(@ValueSafe Object x) { return x == null ? ZERO : (Complex) x; } // utility methods and constants: public Complex plus(Complex c) { return new Complex(re+c.re, im+c.im); } public Complex minus(Complex c) { return new Complex(re-c.re, im-c.im); } public double abs() { return Math.sqrt(re*re + im*im); } public static final Complex PI = valueOf(Math.PI, 0.0); public static final Complex ZERO = valueOf(0.0, 0.0); } This is not a minimal definition, because it includes some utility methods and other optional parts. The essential elements are as follows: The class is marked as a value type with an annotation. The class is final, because it does not make sense to create subclasses of value types. The fields of the class are all non-private and final. (I.e., the type is immutable and structurally transparent.) From the supertype Object, all public non-final methods are overridden. The constructor is private. Beyond these bare essentials, we can observe the following features in this example, which are likely to be typical of all value types: One or more factory methods are responsible for value creation, including a component-wise valueOf method. There are utility methods for complex arithmetic and instance creation, such as plus and changeIm. There are static utility constants, such as PI. The type is serializable, using the default mechanisms. There are methods for converting to and from dynamically typed references, such as asList and cast. The Rules In order to use value types properly, the programmer must avoid value-unsafe operations. A helpful Java compiler should issue errors (or at least warnings) for code which provably applies value-unsafe operations, and should issue warnings for code which might be correct but does not provably avoid value-unsafe operations. No such compilers exist today, but to simplify our account here, we will pretend that they do exist. A value-safe type is any class, interface, or type parameter marked with the @ValueSafe annotation, or any subtype of a value-safe type. If a value-safe class is marked final, it is in fact a value type. All other value-safe classes must be abstract. The non-static fields of a value class must be non-public and final, and all its constructors must be private. Under the above rules, a standard interface could be helpful to define value types like Complex. Here is an example: @ValueSafe public interface ValueType extends java.io.Serializable { // All methods listed here must get redefined. // Definitions must be value-safe, which means // they may depend on component values only. List<? extends Object> asList(); int hashCode(); boolean equals(@ValueSafe Object c); String toString(); } //@ValueSafe inherited from supertype: public final class Complex implements ValueType { … The main advantage of such a conventional interface is that (unlike an annotation) it is reified in the runtime type system. It could appear as an element type or parameter bound, for facilities which are designed to work on value types only. More broadly, it might assist the JVM to perform dynamic enforcement of the rules for value types. Besides types, the annotation @ValueSafe can mark fields, parameters, local variables, and methods. (This is redundant when the type is also value-safe, but may be useful when the type is Object or another supertype of a value type.) Working forward from these annotations, an expression E is defined as value-safe if it satisfies one or more of the following: The type of E is a value-safe type. E names a field, parameter, or local variable whose declaration is marked @ValueSafe. E is a call to a method whose declaration is marked @ValueSafe. E is an assignment to a value-safe variable, field reference, or array reference. E is a cast to a value-safe type from a value-safe expression. E is a conditional expression E0 ? E1 : E2, and both E1 and E2 are value-safe. Assignments to value-safe expressions and initializations of value-safe names must take their values from value-safe expressions. A value-safe expression may not be the subject of a value-unsafe operation. In particular, it cannot be synchronized on, nor can it be compared with the “==” operator, not even with a null or with another value-safe type. In a program where all of these rules are followed, no value-type value will be subject to a value-unsafe operation. Thus, the prime axiom of value types will be satisfied, that no two value type will be distinguishable as long as their component values are equal. More Code To illustrate these rules, here are some usage examples for Complex: Complex pi = Complex.valueOf(Math.PI, 0); Complex zero = pi.changeRe(0); //zero = pi; zero.re = 0; ValueType vtype = pi; @SuppressWarnings("value-unsafe") Object obj = pi; @ValueSafe Object obj2 = pi; obj2 = new Object(); // ok List<Complex> clist = new ArrayList<Complex>(); clist.add(pi); // (ok assuming List.add param is @ValueSafe) List<ValueType> vlist = new ArrayList<ValueType>(); vlist.add(pi); // (ok) List<Object> olist = new ArrayList<Object>(); olist.add(pi); // warning: "value-unsafe" boolean z = pi.equals(zero); boolean z1 = (pi == zero); // error: reference comparison on value type boolean z2 = (pi == null); // error: reference comparison on value type boolean z3 = (pi == obj2); // error: reference comparison on value type synchronized (pi) { } // error: synch of value, unpredictable result synchronized (obj2) { } // unpredictable result Complex qq = pi; qq = null; // possible NPE; warning: “null-unsafe" qq = (Complex) obj; // warning: “null-unsafe" qq = Complex.cast(obj); // OK @SuppressWarnings("null-unsafe") Complex empty = null; // possible NPE qq = empty; // possible NPE (null pollution) The Payoffs It follows from this that either the JVM or the java compiler can replace boxed value-type values with unboxed ones, without affecting normal computations. Fields and variables of value types can be split into their unboxed components. Non-static methods on value types can be transformed into static methods which take the components as value parameters. Some common questions arise around this point in any discussion of value types. Why burden the programmer with all these extra rules? Why not detect programs automagically and perform unboxing transparently? The answer is that it is easy to break the rules accidently unless they are agreed to by the programmer and enforced. Automatic unboxing optimizations are tantalizing but (so far) unreachable ideal. In the current state of the art, it is possible exhibit benchmarks in which automatic unboxing provides the desired effects, but it is not possible to provide a JVM with a performance model that assures the programmer when unboxing will occur. This is why I’m writing this note, to enlist help from, and provide assurances to, the programmer. Basically, I’m shooting for a good set of user-supplied “pragmas” to frame the desired optimization. Again, the important thing is that the unboxing must be done reliably, or else programmers will have no reason to work with the extra complexity of the value-safety rules. There must be a reasonably stable performance model, wherein using a value type has approximately the same performance characteristics as writing the unboxed components as separate Java variables. There are some rough corners to the present scheme. Since Java fields and array elements are initialized to null, value-type computations which incorporate uninitialized variables can produce null pointer exceptions. One workaround for this is to require such variables to be null-tested, and the result replaced with a suitable all-zero value of the value type. That is what the “cast” method does above. Generically typed APIs like List<T> will continue to manipulate boxed values always, at least until we figure out how to do reification of generic type instances. Use of such APIs will elicit warnings until their type parameters (and/or relevant members) are annotated or typed as value-safe. Retrofitting List<T> is likely to expose flaws in the present scheme, which we will need to engineer around. Here are a couple of first approaches: public interface java.util.List<@ValueSafe T> extends Collection<T> { … public interface java.util.List<T extends Object|ValueType> extends Collection<T> { … (The second approach would require disjunctive types, in which value-safety is “contagious” from the constituent types.) With more transformations, the return value types of methods can also be unboxed. This may require significant bytecode-level transformations, and would work best in the presence of a bytecode representation for multiple value groups, which I have proposed elsewhere under the title “Tuples in the VM”. But for starters, the JVM can apply this transformation under the covers, to internally compiled methods. This would give a way to express multiple return values and structured return values, which is a significant pain-point for Java programmers, especially those who work with low-level structure types favored by modern vector and graphics processors. The lack of multiple return values has a strong distorting effect on many Java APIs. Even if the JVM fails to unbox a value, there is still potential benefit to the value type. Clustered computing systems something have copy operations (serialization or something similar) which apply implicitly to command operands. When copying JVM objects, it is extremely helpful to know when an object’s identity is important or not. If an object reference is a copied operand, the system may have to create a proxy handle which points back to the original object, so that side effects are visible. Proxies must be managed carefully, and this can be expensive. On the other hand, value types are exactly those types which a JVM can “copy and forget” with no downside. Array types are crucial to bulk data interfaces. (As data sizes and rates increase, bulk data becomes more important than scalar data, so arrays are definitely accompanying us into the future of computing.) Value types are very helpful for adding structure to bulk data, so a successful value type mechanism will make it easier for us to express richer forms of bulk data. Unboxing arrays (i.e., arrays containing unboxed values) will provide better cache and memory density, and more direct data movement within clustered or heterogeneous computing systems. They require the deepest transformations, relative to today’s JVM. There is an impedance mismatch between value-type arrays and Java’s covariant array typing, so compromises will need to be struck with existing Java semantics. It is probably worth the effort, since arrays of unboxed value types are inherently more memory-efficient than standard Java arrays, which rely on dependent pointer chains. It may be sufficient to extend the “value-safe” concept to array declarations, and allow low-level transformations to change value-safe array declarations from the standard boxed form into an unboxed tuple-based form. Such value-safe arrays would not be convertible to Object[] arrays. Certain connection points, such as Arrays.copyOf and System.arraycopy might need additional input/output combinations, to allow smooth conversion between arrays with boxed and unboxed elements. Alternatively, the correct solution may have to wait until we have enough reification of generic types, and enough operator overloading, to enable an overhaul of Java arrays. Implicit Method Definitions The example of class Complex above may be unattractively complex. I believe most or all of the elements of the example class are required by the logic of value types. If this is true, a programmer who writes a value type will have to write lots of error-prone boilerplate code. On the other hand, I think nearly all of the code (except for the domain-specific parts like plus and minus) can be implicitly generated. Java has a rule for implicitly defining a class’s constructor, if no it defines no constructors explicitly. Likewise, there are rules for providing default access modifiers for interface members. Because of the highly regular structure of value types, it might be reasonable to perform similar implicit transformations on value types. Here’s an example of a “highly implicit” definition of a complex number type: public class Complex implements ValueType { // implicitly final public double re, im; // implicitly public final //implicit methods are defined elementwise from te fields: // toString, asList, equals(2), hashCode, valueOf, cast //optionally, explicit methods (plus, abs, etc.) would go here } In other words, with the right defaults, a simple value type definition can be a one-liner. The observant reader will have noticed the similarities (and suitable differences) between the explicit methods above and the corresponding methods for List<T>. Another way to abbreviate such a class would be to make an annotation the primary trigger of the functionality, and to add the interface(s) implicitly: public @ValueType class Complex { … // implicitly final, implements ValueType (But to me it seems better to communicate the “magic” via an interface, even if it is rooted in an annotation.) Implicitly Defined Value Types So far we have been working with nominal value types, which is to say that the sequence of typed components is associated with a name and additional methods that convey the intention of the programmer. A simple ordered pair of floating point numbers can be variously interpreted as (to name a few possibilities) a rectangular or polar complex number or Cartesian point. The name and the methods convey the intended meaning. But what if we need a truly simple ordered pair of floating point numbers, without any further conceptual baggage? Perhaps we are writing a method (like “divideAndRemainder”) which naturally returns a pair of numbers instead of a single number. Wrapping the pair of numbers in a nominal type (like “QuotientAndRemainder”) makes as little sense as wrapping a single return value in a nominal type (like “Quotient”). What we need here are structural value types commonly known as tuples. For the present discussion, let us assign a conventional, JVM-friendly name to tuples, roughly as follows: public class java.lang.tuple.$DD extends java.lang.tuple.Tuple { double $1, $2; } Here the component names are fixed and all the required methods are defined implicitly. The supertype is an abstract class which has suitable shared declarations. The name itself mentions a JVM-style method parameter descriptor, which may be “cracked” to determine the number and types of the component fields. The odd thing about such a tuple type (and structural types in general) is it must be instantiated lazily, in response to linkage requests from one or more classes that need it. The JVM and/or its class loaders must be prepared to spin a tuple type on demand, given a simple name reference, $xyz, where the xyz is cracked into a series of component types. (Specifics of naming and name mangling need some tasteful engineering.) Tuples also seem to demand, even more than nominal types, some support from the language. (This is probably because notations for non-nominal types work best as combinations of punctuation and type names, rather than named constructors like Function3 or Tuple2.) At a minimum, languages with tuples usually (I think) have some sort of simple bracket notation for creating tuples, and a corresponding pattern-matching syntax (or “destructuring bind”) for taking tuples apart, at least when they are parameter lists. Designing such a syntax is no simple thing, because it ought to play well with nominal value types, and also with pre-existing Java features, such as method parameter lists, implicit conversions, generic types, and reflection. That is a task for another day. Other Use Cases Besides complex numbers and simple tuples there are many use cases for value types. Many tuple-like types have natural value-type representations. These include rational numbers, point locations and pixel colors, and various kinds of dates and addresses. Other types have a variable-length ‘tail’ of internal values. The most common example of this is String, which is (mathematically) a sequence of UTF-16 character values. Similarly, bit vectors, multiple-precision numbers, and polynomials are composed of sequences of values. Such types include, in their representation, a reference to a variable-sized data structure (often an array) which (somehow) represents the sequence of values. The value type may also include ’header’ information. Variable-sized values often have a length distribution which favors short lengths. In that case, the design of the value type can make the first few values in the sequence be direct ’header’ fields of the value type. In the common case where the header is enough to represent the whole value, the tail can be a shared null value, or even just a null reference. Note that the tail need not be an immutable object, as long as the header type encapsulates it well enough. This is the case with String, where the tail is a mutable (but never mutated) character array. Field types and their order must be a globally visible part of the API. The structure of the value type must be transparent enough to have a globally consistent unboxed representation, so that all callers and callees agree about the type and order of components that appear as parameters, return types, and array elements. This is a trade-off between efficiency and encapsulation, which is forced on us when we remove an indirection enjoyed by boxed representations. A JVM-only transformation would not care about such visibility, but a bytecode transformation would need to take care that (say) the components of complex numbers would not get swapped after a redefinition of Complex and a partial recompile. Perhaps constant pool references to value types need to declare the field order as assumed by each API user. This brings up the delicate status of private fields in a value type. It must always be possible to load, store, and copy value types as coordinated groups, and the JVM performs those movements by moving individual scalar values between locals and stack. If a component field is not public, what is to prevent hostile code from plucking it out of the tuple using a rogue aload or astore instruction? Nothing but the verifier, so we may need to give it more smarts, so that it treats value types as inseparable groups of stack slots or locals (something like long or double). My initial thought was to make the fields always public, which would make the security problem moot. But public is not always the right answer; consider the case of String, where the underlying mutable character array must be encapsulated to prevent security holes. I believe we can win back both sides of the tradeoff, by training the verifier never to split up the components in an unboxed value. Just as the verifier encapsulates the two halves of a 64-bit primitive, it can encapsulate the the header and body of an unboxed String, so that no code other than that of class String itself can take apart the values. Similar to String, we could build an efficient multi-precision decimal type along these lines: public final class DecimalValue extends ValueType { protected final long header; protected private final BigInteger digits; public DecimalValue valueOf(int value, int scale) { assert(scale >= 0); return new DecimalValue(((long)value << 32) + scale, null); } public DecimalValue valueOf(long value, int scale) { if (value == (int) value) return valueOf((int)value, scale); return new DecimalValue(-scale, new BigInteger(value)); } } Values of this type would be passed between methods as two machine words. Small values (those with a significand which fits into 32 bits) would be represented without any heap data at all, unless the DecimalValue itself were boxed. (Note the tension between encapsulation and unboxing in this case. It would be better if the header and digits fields were private, but depending on where the unboxing information must “leak”, it is probably safer to make a public revelation of the internal structure.) Note that, although an array of Complex can be faked with a double-length array of double, there is no easy way to fake an array of unboxed DecimalValues. (Either an array of boxed values or a transposed pair of homogeneous arrays would be reasonable fallbacks, in a current JVM.) Getting the full benefit of unboxing and arrays will require some new JVM magic. Although the JVM emphasizes portability, system dependent code will benefit from using machine-level types larger than 64 bits. For example, the back end of a linear algebra package might benefit from value types like Float4 which map to stock vector types. This is probably only worthwhile if the unboxing arrays can be packed with such values. More Daydreams A more finely-divided design for dynamic enforcement of value safety could feature separate marker interfaces for each invariant. An empty marker interface Unsynchronizable could cause suitable exceptions for monitor instructions on objects in marked classes. More radically, a Interchangeable marker interface could cause JVM primitives that are sensitive to object identity to raise exceptions; the strangest result would be that the acmp instruction would have to be specified as raising an exception. @ValueSafe public interface ValueType extends java.io.Serializable, Unsynchronizable, Interchangeable { … public class Complex implements ValueType { // inherits Serializable, Unsynchronizable, Interchangeable, @ValueSafe … It seems possible that Integer and the other wrapper types could be retro-fitted as value-safe types. This is a major change, since wrapper objects would be unsynchronizable and their references interchangeable. It is likely that code which violates value-safety for wrapper types exists but is uncommon. It is less plausible to retro-fit String, since the prominent operation String.intern is often used with value-unsafe code. We should also reconsider the distinction between boxed and unboxed values in code. The design presented above obscures that distinction. As another thought experiment, we could imagine making a first class distinction in the type system between boxed and unboxed representations. Since only primitive types are named with a lower-case initial letter, we could define that the capitalized version of a value type name always refers to the boxed representation, while the initial lower-case variant always refers to boxed. For example: complex pi = complex.valueOf(Math.PI, 0); Complex boxPi = pi; // convert to boxed myList.add(boxPi); complex z = myList.get(0); // unbox Such a convention could perhaps absorb the current difference between int and Integer, double and Double. It might also allow the programmer to express a helpful distinction among array types. As said above, array types are crucial to bulk data interfaces, but are limited in the JVM. Extending arrays beyond the present limitations is worth thinking about; for example, the Maxine JVM implementation has a hybrid object/array type. Something like this which can also accommodate value type components seems worthwhile. On the other hand, does it make sense for value types to contain short arrays? And why should random-access arrays be the end of our design process, when bulk data is often sequentially accessed, and it might make sense to have heterogeneous streams of data as the natural “jumbo” data structure. These considerations must wait for another day and another note. More Work It seems to me that a good sequence for introducing such value types would be as follows: Add the value-safety restrictions to an experimental version of javac. Code some sample applications with value types, including Complex and DecimalValue. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so. Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. A staggered roll-out like this would decouple language changes from bytecode changes, which is always a convenient thing. A similar investigation should be applied (concurrently) to array types. In this case, it seems to me that the starting point is in the JVM: Add an experimental unboxing array data structure to a production JVM, perhaps along the lines of Maxine hybrids. No bytecode or language support is required at first; everything can be done with encapsulated unsafe operations and/or method handles. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so. Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. That’s enough musing me for now. Back to work!

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Java Cloud Service Integration to REST Service

- by Jani Rautiainen

Service (JCS) provides a platform to develop and deploy business applications in the cloud. In Fusion Applications Cloud deployments customers do not have the option to deploy custom applications developed with JDeveloper to ensure the integrity and supportability of the hosted application service. Instead the custom applications can be deployed to the JCS and integrated to the Fusion Application Cloud instance. This series of articles will go through the features of JCS, provide end-to-end examples on how to develop and deploy applications on JCS and how to integrate them with the Fusion Applications instance. In this article a custom application integrating with REST service will be implemented. We will use REST services provided by Taleo as an example; however the same approach will work with any REST service. In this example the data from the REST service is used to populate a dynamic table. Pre-requisites Access to Cloud instance In order to deploy the application access to a JCS instance is needed, a free trial JCS instance can be obtained from Oracle Cloud site. To register you will need a credit card even if the credit card will not be charged. To register simply click "Try it" and choose the "Java" option. The confirmation email will contain the connection details. See this video for example of the registration.Once the request is processed you will be assigned 2 service instances; Java and Database. Applications deployed to the JCS must use Oracle Database Cloud Service as their underlying database. So when JCS instance is created a database instance is associated with it using a JDBC data source.The cloud services can be monitored and managed through the web UI. For details refer to Getting Started with Oracle Cloud. JDeveloper JDeveloper contains Cloud specific features related to e.g. connection and deployment. To use these features download the JDeveloper from JDeveloper download site by clicking the "Download JDeveloper 11.1.1.7.1 for ADF deployment on Oracle Cloud" link, this version of JDeveloper will have the JCS integration features that will be used in this article. For versions that do not include the Cloud integration features the Oracle Java Cloud Service SDK or the JCS Java Console can be used for deployment. For details on installing and configuring the JDeveloper refer to the installation guideFor details on SDK refer to Using the Command-Line Interface to Monitor Oracle Java Cloud Service and Using the Command-Line Interface to Manage Oracle Java Cloud Service. Access to a local database The database associated with the JCS instance cannot be connected to with JDBC. Since creating ADFbc business component requires a JDBC connection we will need access to a local database. 3rd party libraries This example will use some 3rd party libraries for implementing the REST service call and processing the input / output content. Other libraries may also be used, however these are tested to work. Jersey 1.x Jersey library will be used as a client to make the call to the REST service. JCS documentation for supported specifications states: Java API for RESTful Web Services (JAX-RS) 1.1 So Jersey 1.x will be used. Download the single-JAR Jersey bundle; in this example Jersey 1.18 JAR bundle is used. Json-simple Jjson-simple library will be used to process the json objects. Download the JAR file; in this example json-simple-1.1.1.jar is used. Accessing data in Taleo Before implementing the application it is beneficial to familiarize oneself with the data in Taleo. Easiest way to do this is by using a RESTClient on your browser. Once added to the browser you can access the UI: The client can be used to call the REST services to test the URLs and data before adding them into the application. First derive the base URL for the service this can be done with: Method: GET URL: https://tbe.taleo.net/MANAGER/dispatcher/api/v1/serviceUrl/<company name> The response will contain the base URL to be used for the service calls for the company. Next obtain authentication token with: Method: POST URL: https://ch.tbe.taleo.net/CH07/ats/api/v1/login?orgCode=<company>&userName=<user name>&password=<password> The response includes an authentication token that can be used for few hours to authenticate with the service: { "response": { "authToken": "webapi26419680747505890557" }, "status": { "detail": {}, "success": true } } To authenticate the service calls navigate to "Headers -> Custom Header": And add a new request header with: Name: Cookie Value: authToken=webapi26419680747505890557 Once authentication token is defined the tool can be used to invoke REST services; for example: Method: GET URL: https://ch.tbe.taleo.net/CH07/ats/api/v1/object/candidate/search.xml?status=16 This data will be used on the application to be created. For details on the Taleo REST services refer to the Taleo Business Edition REST API Guide. Create Application First Fusion Web Application is created and configured. Start JDeveloper and click "New Application": Application Name: JcsRestDemo Application Package Prefix: oracle.apps.jcs.test Application Template: Fusion Web Application (ADF) Configure Local Cloud Connection Follow the steps documented in the "Java Cloud Service ADF Web Application" article to configure a local database connection needed to create the ADFbc objects. Configure Libraries Add the 3rd party libraries into the class path. Create the following directory and copy the jar files into it: <JDEV_USER_HOME>/JcsRestDemo/lib Select the "Model" project, navigate "Application -> Project Properties -> Libraries and Classpath -> Add JAR / Directory" and add the 2 3rd party libraries: Accessing Data from Taleo To access data from Taleo using the REST service the 3rd party libraries will be used. 2 Java classes are implemented, one representing the Candidate object and another for accessing the Taleo repository Candidate Candidate object is a POJO object used to represent the candidate data obtained from the Taleo repository. The data obtained will be used to populate the ADFbc object used to display the data on the UI. The candidate object contains simply the variables we obtain using the REST services and the getters / setters for them: Navigate "New -> General -> Java -> Java Class", enter "Candidate" as the name and create it in the package "oracle.apps.jcs.test.model". Copy / paste the following as the content: import oracle.jbo.domain.Number; public class Candidate { private Number candId; private String firstName; private String lastName; public Candidate() { super(); } public Candidate(Number candId, String firstName, String lastName) { super(); this.candId = candId; this.firstName = firstName; this.lastName = lastName; } public void setCandId(Number candId) { this.candId = candId; } public Number getCandId() { return candId; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getFirstName() { return firstName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getLastName() { return lastName; } } Taleo Repository Taleo repository class will interact with the Taleo REST services. The logic will query data from Taleo and populate Candidate objects with the data. The Candidate object will then be used to populate the ADFbc object used to display data on the UI. Navigate "New -> General -> Java -> Java Class", enter "TaleoRepository" as the name and create it in the package "oracle.apps.jcs.test.model". Copy / paste the following as the content (for details of the implementation refer to the documentation in the code): import com.sun.jersey.api.client.Client; import com.sun.jersey.api.client.ClientResponse; import com.sun.jersey.api.client.WebResource; import com.sun.jersey.core.util.MultivaluedMapImpl; import java.io.StringReader; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import java.util.Map; import javax.ws.rs.core.MediaType; import javax.ws.rs.core.MultivaluedMap; import oracle.jbo.domain.Number; import org.json.simple.JSONArray; import org.json.simple.JSONObject; import org.json.simple.parser.JSONParser; /** * This class interacts with the Taleo REST services */ public class TaleoRepository { /** * Connection information needed to access the Taleo services */ String _company = null; String _userName = null; String _password = null; /** * Jersey client used to access the REST services */ Client _client = null; /** * Parser for processing the JSON objects used as * input / output for the services */ JSONParser _parser = null; /** * The base url for constructing the REST URLs. This is obtained * from Taleo with a service call */ String _baseUrl = null; /** * Authentication token obtained from Taleo using a service call. * The token can be used to authenticate on subsequent * service calls. The token will expire in 4 hours */ String _authToken = null; /** * Static url that can be used to obtain the url used to construct * service calls for a given company */ private static String _taleoUrl = "https://tbe.taleo.net/MANAGER/dispatcher/api/v1/serviceUrl/"; /** * Default constructor for the repository * Authentication details are passed as parameters and used to generate * authentication token. Note that each service call will * generate its own token. This is done to avoid dealing with the expiry * of the token. Also only 20 tokens are allowed per user simultaneously. * So instead for each call there is login / logout. * * @param company the company for which the service calls are made * @param userName the user name to authenticate with * @param password the password to authenticate with. */ public TaleoRepository(String company, String userName, String password) { super(); _company = company; _userName = userName; _password = password; _client = Client.create(); _parser = new JSONParser(); _baseUrl = getBaseUrl(); } /** * This obtains the base url for a company to be used * to construct the urls for service calls * @return base url for the service calls */ private String getBaseUrl() { String result = null; if (null != _baseUrl) { result = _baseUrl; } else { try { String company = _company; WebResource resource = _client.resource(_taleoUrl + company); ClientResponse response = resource.type(MediaType.APPLICATION_FORM_URLENCODED_TYPE).get(ClientResponse.class); String entity = response.getEntity(String.class); JSONObject jsonObject = (JSONObject)_parser.parse(new StringReader(entity)); JSONObject jsonResponse = (JSONObject)jsonObject.get("response"); result = (String)jsonResponse.get("URL"); } catch (Exception ex) { ex.printStackTrace(); } } return result; } /** * Generates authentication token, that can be used to authenticate on * subsequent service calls. Note that each service call will * generate its own token. This is done to avoid dealing with the expiry * of the token. Also only 20 tokens are allowed per user simultaneously. * So instead for each call there is login / logout. * @return authentication token that can be used to authenticate on * subsequent service calls */ private String login() { String result = null; try { MultivaluedMap<String, String> formData = new MultivaluedMapImpl(); formData.add("orgCode", _company); formData.add("userName", _userName); formData.add("password", _password); WebResource resource = _client.resource(_baseUrl + "login"); ClientResponse response = resource.type(MediaType.APPLICATION_FORM_URLENCODED_TYPE).post(ClientResponse.class, formData); String entity = response.getEntity(String.class); JSONObject jsonObject = (JSONObject)_parser.parse(new StringReader(entity)); JSONObject jsonResponse = (JSONObject)jsonObject.get("response"); result = (String)jsonResponse.get("authToken"); } catch (Exception ex) { throw new RuntimeException("Unable to login ", ex); } if (null == result) throw new RuntimeException("Unable to login "); return result; } /** * Releases a authentication token. Each call to login must be followed * by call to logout after the processing is done. This is required as * the tokens are limited to 20 per user and if not released the tokens * will only expire after 4 hours. * @param authToken */ private void logout(String authToken) { WebResource resource = _client.resource(_baseUrl + "logout"); resource.header("cookie", "authToken=" + authToken).post(ClientResponse.class); } /** * This method is used to obtain a list of candidates using a REST * service call. At this example the query is hard coded to query * based on status. The url constructed to access the service is: * <_baseUrl>/object/candidate/search.xml?status=16 * @return List of candidates obtained with the service call */ public List<Candidate> getCandidates() { List<Candidate> result = new ArrayList<Candidate>(); try { // First login, note that in finally block we must have logout _authToken = "authToken=" + login(); /** * Construct the URL, the resulting url will be: * <_baseUrl>/object/candidate/search.xml?status=16 */ MultivaluedMap<String, String> formData = new MultivaluedMapImpl(); formData.add("status", "16"); JSONArray searchResults = (JSONArray)getTaleoResource("object/candidate/search", "searchResults", formData); /** * Process the results, the resulting JSON object is something like * this (simplified for readability): * * { * "response": * { * "searchResults": * [ * { * "candidate": * { * "candId": 211, * "firstName": "Mary", * "lastName": "Stochi", * logic here will find the candidate object(s), obtain the desired * data from them, construct a Candidate object based on the data * and add it to the results. */ for (Object object : searchResults) { JSONObject temp = (JSONObject)object; JSONObject candidate = (JSONObject)findObject(temp, "candidate"); Long candIdTemp = (Long)candidate.get("candId"); Number candId = (null == candIdTemp ? null : new Number(candIdTemp)); String firstName = (String)candidate.get("firstName"); String lastName = (String)candidate.get("lastName"); result.add(new Candidate(candId, firstName, lastName)); } } catch (Exception ex) { ex.printStackTrace(); } finally { if (null != _authToken) logout(_authToken); } return result; } /** * Convenience method to construct url for the service call, invoke the * service and obtain a resource from the response * @param path the path for the service to be invoked. This is combined * with the base url to construct a url for the service * @param resource the key for the object in the response that will be * obtained * @param parameters any parameters used for the service call. The call * is slightly different depending whether parameters exist or not. * @return the resource from the response for the service call */ private Object getTaleoResource(String path, String resource, MultivaluedMap<String, String> parameters) { Object result = null; try { WebResource webResource = _client.resource(_baseUrl + path); ClientResponse response = null; if (null == parameters) response = webResource.header("cookie", _authToken).get(ClientResponse.class); else response = webResource.queryParams(parameters).header("cookie", _authToken).get(ClientResponse.class); String entity = response.getEntity(String.class); JSONObject jsonObject = (JSONObject)_parser.parse(new StringReader(entity)); result = findObject(jsonObject, resource); } catch (Exception ex) { ex.printStackTrace(); } return result; } /** * Convenience method to recursively find a object with an key * traversing down from a given root object. This will traverse a * JSONObject / JSONArray recursively to find a matching key, if found * the object with the key is returned. * @param root root object which contains the key searched for * @param key the key for the object to search for * @return the object matching the key */ private Object findObject(Object root, String key) { Object result = null; if (root instanceof JSONObject) { JSONObject rootJSON = (JSONObject)root; if (rootJSON.containsKey(key)) { result = rootJSON.get(key); } else { Iterator children = rootJSON.entrySet().iterator(); while (children.hasNext()) { Map.Entry entry = (Map.Entry)children.next(); Object child = entry.getValue(); if (child instanceof JSONObject || child instanceof JSONArray) { result = findObject(child, key); if (null != result) break; } } } } else if (root instanceof JSONArray) { JSONArray rootJSON = (JSONArray)root; for (Object child : rootJSON) { if (child instanceof JSONObject || child instanceof JSONArray) { result = findObject(child, key); if (null != result) break; } } } return result; } } Creating Business Objects While JCS application can be created without a local database, the local database is required when using ADFbc objects even if database objects are not referred. For this example we will create a "Transient" view object that will be programmatically populated based the data obtained from Taleo REST services. Creating ADFbc objects Choose the "Model" project and navigate "New -> Business Tier : ADF Business Components : View Object". On the "Initialize Business Components Project" choose the local database connection created in previous step. On Step 1 enter "JcsRestDemoVO" on the "Name" and choose "Rows populated programmatically, not based on query": On step 2 create the following attributes: CandId Type: Number Updatable: Always Key Attribute: checked Name Type: String Updatable: Always On steps 3 and 4 accept defaults and click "Next". On step 5 check the "Application Module" checkbox and enter "JcsRestDemoAM" as the name: Click "Finish" to generate the objects. Populating the VO To display the data on the UI the "transient VO" is populated programmatically based on the data obtained from the Taleo REST services. Open the "JcsRestDemoVOImpl.java". Copy / paste the following as the content (for details of the implementation refer to the documentation in the code): import java.sql.ResultSet; import java.util.List; import java.util.ListIterator; import oracle.jbo.server.ViewObjectImpl; import oracle.jbo.server.ViewRowImpl; import oracle.jbo.server.ViewRowSetImpl; // --------------------------------------------------------------------- // --- File generated by Oracle ADF Business Components Design Time. // --- Tue Feb 18 09:40:25 PST 2014 // --- Custom code may be added to this class. // --- Warning: Do not modify method signatures of generated methods. // --------------------------------------------------------------------- public class JcsRestDemoVOImpl extends ViewObjectImpl { /** * This is the default constructor (do not remove). */ public JcsRestDemoVOImpl() { } @Override public void executeQuery() { /** * For some reason we need to reset everything, otherwise * 2nd entry to the UI screen may fail with * "java.util.NoSuchElementException" in createRowFromResultSet * call to "candidates.next()". I am not sure why this is happening * as the Iterator is new and "hasNext" is true at the point * of the execution. My theory is that since the iterator object is * exactly the same the VO cache somehow reuses the iterator including * the pointer that has already exhausted the iterable elements on the * previous run. Working around the issue * here by cleaning out everything on the VO every time before query * is executed on the VO. */ getViewDef().setQuery(null); getViewDef().setSelectClause(null); setQuery(null); this.reset(); this.clearCache(); super.executeQuery(); } /** * executeQueryForCollection - overridden for custom java data source support. */ protected void executeQueryForCollection(Object qc, Object[] params, int noUserParams) { /** * Integrate with the Taleo REST services using TaleoRepository class. * A list of candidates matching a hard coded query is obtained. */ TaleoRepository repository = new TaleoRepository(<company>, <username>, <password>); List<Candidate> candidates = repository.getCandidates(); /** * Store iterator for the candidates as user data on the collection. * This will be used in createRowFromResultSet to create rows based on * the custom iterator. */ ListIterator<Candidate> candidatescIterator = candidates.listIterator(); setUserDataForCollection(qc, candidatescIterator); super.executeQueryForCollection(qc, params, noUserParams); } /** * hasNextForCollection - overridden for custom java data source support. */ protected boolean hasNextForCollection(Object qc) { boolean result = false; /** * Determines whether there are candidates for which to create a row */ ListIterator<Candidate> candidates = (ListIterator<Candidate>)getUserDataForCollection(qc); result = candidates.hasNext(); /** * If all candidates to be created indicate that processing is done */ if (!result) { setFetchCompleteForCollection(qc, true); } return result; } /** * createRowFromResultSet - overridden for custom java data source support. */ protected ViewRowImpl createRowFromResultSet(Object qc, ResultSet resultSet) { /** * Obtain the next candidate from the collection and create a row * for it. */ ListIterator<Candidate> candidates = (ListIterator<Candidate>)getUserDataForCollection(qc); ViewRowImpl row = createNewRowForCollection(qc); try { Candidate candidate = candidates.next(); row.setAttribute("CandId", candidate.getCandId()); row.setAttribute("Name", candidate.getFirstName() + " " + candidate.getLastName()); } catch (Exception e) { e.printStackTrace(); } return row; } /** * getQueryHitCount - overridden for custom java data source support. */ public long getQueryHitCount(ViewRowSetImpl viewRowSet) { /** * For this example this is not implemented rather we always return 0. */ return 0; } } Creating UI Choose the "ViewController" project and navigate "New -> Web Tier : JSF : JSF Page". On the "Create JSF Page" enter "JcsRestDemo" as name and ensure that the "Create as XML document (*.jspx)" is checked. Open "JcsRestDemo.jspx" and navigate to "Data Controls -> JcsRestDemoAMDataControl -> JcsRestDemoVO1" and drag & drop the VO to the "<af:form> " as a "ADF Read-only Table": Accept the defaults in "Edit Table Columns". To execute the query navigate to to "Data Controls -> JcsRestDemoAMDataControl -> JcsRestDemoVO1 -> Operations -> Execute" and drag & drop the operation to the "<af:form> " as a "Button": Deploying to JCS Follow the same steps as documented in previous article"Java Cloud Service ADF Web Application". Once deployed the application can be accessed with URL: https://java-[identity domain].java.[data center].oraclecloudapps.com/JcsRestDemo-ViewController-context-root/faces/JcsRestDemo.jspx The UI displays a list of candidates obtained from the Taleo REST Services: Summary In this article we learned how to integrate with REST services using Jersey library in JCS. In future articles various other integration techniques will be covered.

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256 Windows Azure Worker Roles, Windows Kinect and a 90's Text-Based Ray-Tracer

- by Alan Smith

For a couple of years I have been demoing a simple render farm hosted in Windows Azure using worker roles and the Azure Storage service. At the start of the presentation I deploy an Azure application that uses 16 worker roles to render a 1,500 frame 3D ray-traced animation. At the end of the presentation, when the animation was complete, I would play the animation delete the Azure deployment. The standing joke with the audience was that it was that it was a “$2 demo”, as the compute charges for running the 16 instances for an hour was $1.92, factor in the bandwidth charges and it’s a couple of dollars. The point of the demo is that it highlights one of the great benefits of cloud computing, you pay for what you use, and if you need massive compute power for a short period of time using Windows Azure can work out very cost effective. The “$2 demo” was great for presenting at user groups and conferences in that it could be deployed to Azure, used to render an animation, and then removed in a one hour session. I have always had the idea of doing something a bit more impressive with the demo, and scaling it from a “$2 demo” to a “$30 demo”. The challenge was to create a visually appealing animation in high definition format and keep the demo time down to one hour. This article will take a run through how I achieved this. Ray Tracing Ray tracing, a technique for generating high quality photorealistic images, gained popularity in the 90’s with companies like Pixar creating feature length computer animations, and also the emergence of shareware text-based ray tracers that could run on a home PC. In order to render a ray traced image, the ray of light that would pass from the view point must be tracked until it intersects with an object. At the intersection, the color, reflectiveness, transparency, and refractive index of the object are used to calculate if the ray will be reflected or refracted. Each pixel may require thousands of calculations to determine what color it will be in the rendered image. Pin-Board Toys Having very little artistic talent and a basic understanding of maths I decided to focus on an animation that could be modeled fairly easily and would look visually impressive. I’ve always liked the pin-board desktop toys that become popular in the 80’s and when I was working as a 3D animator back in the 90’s I always had the idea of creating a 3D ray-traced animation of a pin-board, but never found the energy to do it. Even if I had a go at it, the render time to produce an animation that would look respectable on a 486 would have been measured in months. PolyRay Back in 1995 I landed my first real job, after spending three years being a beach-ski-climbing-paragliding-bum, and was employed to create 3D ray-traced animations for a CD-ROM that school kids would use to learn physics. I had got into the strange and wonderful world of text-based ray tracing, and was using a shareware ray-tracer called PolyRay. PolyRay takes a text file describing a scene as input and, after a few hours processing on a 486, produced a high quality ray-traced image. The following is an example of a basic PolyRay scene file. background Midnight_Blue static define matte surface { ambient 0.1 diffuse 0.7 } define matte_white texture { matte { color white } } define matte_black texture { matte { color dark_slate_gray } } define position_cylindrical 3 define lookup_sawtooth 1 define light_wood <0.6, 0.24, 0.1> define median_wood <0.3, 0.12, 0.03> define dark_wood <0.05, 0.01, 0.005> define wooden texture { noise surface { ambient 0.2 diffuse 0.7 specular white, 0.5 microfacet Reitz 10 position_fn position_cylindrical position_scale 1 lookup_fn lookup_sawtooth octaves 1 turbulence 1 color_map( [0.0, 0.2, light_wood, light_wood] [0.2, 0.3, light_wood, median_wood] [0.3, 0.4, median_wood, light_wood] [0.4, 0.7, light_wood, light_wood] [0.7, 0.8, light_wood, median_wood] [0.8, 0.9, median_wood, light_wood] [0.9, 1.0, light_wood, dark_wood]) } } define glass texture { surface { ambient 0 diffuse 0 specular 0.2 reflection white, 0.1 transmission white, 1, 1.5 }} define shiny surface { ambient 0.1 diffuse 0.6 specular white, 0.6 microfacet Phong 7 } define steely_blue texture { shiny { color black } } define chrome texture { surface { color white ambient 0.0 diffuse 0.2 specular 0.4 microfacet Phong 10 reflection 0.8 } } viewpoint { from <4.000, -1.000, 1.000> at <0.000, 0.000, 0.000> up <0, 1, 0> angle 60 resolution 640, 480 aspect 1.6 image_format 0 } light <-10, 30, 20> light <-10, 30, -20> object { disc <0, -2, 0>, <0, 1, 0>, 30 wooden } object { sphere <0.000, 0.000, 0.000>, 1.00 chrome } object { cylinder <0.000, 0.000, 0.000>, <0.000, 0.000, -4.000>, 0.50 chrome } After setting up the background and defining colors and textures, the viewpoint is specified. The “camera” is located at a point in 3D space, and it looks towards another point. The angle, image resolution, and aspect ratio are specified. Two lights are present in the image at defined coordinates. The three objects in the image are a wooden disc to represent a table top, and a sphere and cylinder that intersect to form a pin that will be used for the pin board toy in the final animation. When the image is rendered, the following image is produced. The pins are modeled with a chrome surface, so they reflect the environment around them. Note that the scale of the pin shaft is not correct, this will be fixed later. Modeling the Pin Board The frame of the pin-board is made up of three boxes, and six cylinders, the front box is modeled using a clear, slightly reflective solid, with the same refractive index of glass. The other shapes are modeled as metal. object { box <-5.5, -1.5, 1>, <5.5, 5.5, 1.2> glass } object { box <-5.5, -1.5, -0.04>, <5.5, 5.5, -0.09> steely_blue } object { box <-5.5, -1.5, -0.52>, <5.5, 5.5, -0.59> steely_blue } object { cylinder <-5.2, -1.2, 1.4>, <-5.2, -1.2, -0.74>, 0.2 steely_blue } object { cylinder <5.2, -1.2, 1.4>, <5.2, -1.2, -0.74>, 0.2 steely_blue } object { cylinder <-5.2, 5.2, 1.4>, <-5.2, 5.2, -0.74>, 0.2 steely_blue } object { cylinder <5.2, 5.2, 1.4>, <5.2, 5.2, -0.74>, 0.2 steely_blue } object { cylinder <0, -1.2, 1.4>, <0, -1.2, -0.74>, 0.2 steely_blue } object { cylinder <0, 5.2, 1.4>, <0, 5.2, -0.74>, 0.2 steely_blue } In order to create the matrix of pins that make up the pin board I used a basic console application with a few nested loops to create two intersecting matrixes of pins, which models the layout used in the pin boards. The resulting image is shown below. The pin board contains 11,481 pins, with the scene file containing 23,709 lines of code. For the complete animation 2,000 scene files will be created, which is over 47 million lines of code. Each pin in the pin-board will slide out a specific distance when an object is pressed into the back of the board. This is easily modeled by setting the Z coordinate of the pin to a specific value. In order to set all of the pins in the pin-board to the correct position, a bitmap image can be used. The position of the pin can be set based on the color of the pixel at the appropriate position in the image. When the Windows Azure logo is used to set the Z coordinate of the pins, the following image is generated. The challenge now was to make a cool animation. The Azure Logo is fine, but it is static. Using a normal video to animate the pins would not work; the colors in the video would not be the same as the depth of the objects from the camera. In order to simulate the pin board accurately a series of frames from a depth camera could be used. Windows Kinect The Kenect controllers for the X-Box 360 and Windows feature a depth camera. The Kinect SDK for Windows provides a programming interface for Kenect, providing easy access for .NET developers to the Kinect sensors. The Kinect Explorer provided with the Kinect SDK is a great starting point for exploring Kinect from a developers perspective. Both the X-Box 360 Kinect and the Windows Kinect will work with the Kinect SDK, the Windows Kinect is required for commercial applications, but the X-Box Kinect can be used for hobby projects. The Windows Kinect has the advantage of providing a mode to allow depth capture with objects closer to the camera, which makes for a more accurate depth image for setting the pin positions. Creating a Depth Field Animation The depth field animation used to set the positions of the pin in the pin board was created using a modified version of the Kinect Explorer sample application. In order to simulate the pin board accurately, a small section of the depth range from the depth sensor will be used. Any part of the object in front of the depth range will result in a white pixel; anything behind the depth range will be black. Within the depth range the pixels in the image will be set to RGB values from 0,0,0 to 255,255,255. A screen shot of the modified Kinect Explorer application is shown below. The Kinect Explorer sample application was modified to include slider controls that are used to set the depth range that forms the image from the depth stream. This allows the fine tuning of the depth image that is required for simulating the position of the pins in the pin board. The Kinect Explorer was also modified to record a series of images from the depth camera and save them as a sequence JPEG files that will be used to animate the pins in the animation the Start and Stop buttons are used to start and stop the image recording. En example of one of the depth images is shown below. Once a series of 2,000 depth images has been captured, the task of creating the animation can begin. Rendering a Test Frame In order to test the creation of frames and get an approximation of the time required to render each frame a test frame was rendered on-premise using PolyRay. The output of the rendering process is shown below. The test frame contained 23,629 primitive shapes, most of which are the spheres and cylinders that are used for the 11,800 or so pins in the pin board. The 1280x720 image contains 921,600 pixels, but as anti-aliasing was used the number of rays that were calculated was 4,235,777, with 3,478,754,073 object boundaries checked. The test frame of the pin board with the depth field image applied is shown below. The tracing time for the test frame was 4 minutes 27 seconds, which means rendering the2,000 frames in the animation would take over 148 hours, or a little over 6 days. Although this is much faster that an old 486, waiting almost a week to see the results of an animation would make it challenging for animators to create, view, and refine their animations. It would be much better if the animation could be rendered in less than one hour. Windows Azure Worker Roles The cost of creating an on-premise render farm to render animations increases in proportion to the number of servers. The table below shows the cost of servers for creating a render farm, assuming a cost of $500 per server. Number of Servers Cost 1 $500 16 $8,000 256 $128,000 As well as the cost of the servers, there would be additional costs for networking, racks etc. Hosting an environment of 256 servers on-premise would require a server room with cooling, and some pretty hefty power cabling. The Windows Azure compute services provide worker roles, which are ideal for performing processor intensive compute tasks. With the scalability available in Windows Azure a job that takes 256 hours to complete could be perfumed using different numbers of worker roles. The time and cost of using 1, 16 or 256 worker roles is shown below. Number of Worker Roles Render Time Cost 1 256 hours $30.72 16 16 hours $30.72 256 1 hour $30.72 Using worker roles in Windows Azure provides the same cost for the 256 hour job, irrespective of the number of worker roles used. Provided the compute task can be broken down into many small units, and the worker role compute power can be used effectively, it makes sense to scale the application so that the task is completed quickly, making the results available in a timely fashion. The task of rendering 2,000 frames in an animation is one that can easily be broken down into 2,000 individual pieces, which can be performed by a number of worker roles. Creating a Render Farm in Windows Azure The architecture of the render farm is shown in the following diagram. The render farm is a hybrid application with the following components: · On-Premise o Windows Kinect – Used combined with the Kinect Explorer to create a stream of depth images. o Animation Creator – This application uses the depth images from the Kinect sensor to create scene description files for PolyRay. These files are then uploaded to the jobs blob container, and job messages added to the jobs queue. o Process Monitor – This application queries the role instance lifecycle table and displays statistics about the render farm environment and render process. o Image Downloader – This application polls the image queue and downloads the rendered animation files once they are complete. · Windows Azure o Azure Storage – Queues and blobs are used for the scene description files and completed frames. A table is used to store the statistics about the rendering environment. The architecture of each worker role is shown below. The worker role is configured to use local storage, which provides file storage on the worker role instance that can be use by the applications to render the image and transform the format of the image. The service definition for the worker role with the local storage configuration highlighted is shown below. <?xml version="1.0" encoding="utf-8"?> <ServiceDefinition name="CloudRay" > <WorkerRole name="CloudRayWorkerRole" vmsize="Small"> <Imports> </Imports> <ConfigurationSettings> <Setting name="DataConnectionString" /> </ConfigurationSettings> <LocalResources> <LocalStorage name="RayFolder" cleanOnRoleRecycle="true" /> </LocalResources> </WorkerRole> </ServiceDefinition> The two executable programs, PolyRay.exe and DTA.exe are included in the Azure project, with Copy Always set as the property. PolyRay will take the scene description file and render it to a Truevision TGA file. As the TGA format has not seen much use since the mid 90’s it is converted to a JPG image using Dave's Targa Animator, another shareware application from the 90’s. Each worker roll will use the following process to render the animation frames. 1. The worker process polls the job queue, if a job is available the scene description file is downloaded from blob storage to local storage. 2. PolyRay.exe is started in a process with the appropriate command line arguments to render the image as a TGA file. 3. DTA.exe is started in a process with the appropriate command line arguments convert the TGA file to a JPG file. 4. The JPG file is uploaded from local storage to the images blob container. 5. A message is placed on the images queue to indicate a new image is available for download. 6. The job message is deleted from the job queue. 7. The role instance lifecycle table is updated with statistics on the number of frames rendered by the worker role instance, and the CPU time used. The code for this is shown below. public override void Run() { // Set environment variables string polyRayPath = Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), PolyRayLocation); string dtaPath = Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), DTALocation); LocalResource rayStorage = RoleEnvironment.GetLocalResource("RayFolder"); string localStorageRootPath = rayStorage.RootPath; JobQueue jobQueue = new JobQueue("renderjobs"); JobQueue downloadQueue = new JobQueue("renderimagedownloadjobs"); CloudRayBlob sceneBlob = new CloudRayBlob("scenes"); CloudRayBlob imageBlob = new CloudRayBlob("images"); RoleLifecycleDataSource roleLifecycleDataSource = new RoleLifecycleDataSource(); Frames = 0; while (true) { // Get the render job from the queue CloudQueueMessage jobMsg = jobQueue.Get(); if (jobMsg != null) { // Get the file details string sceneFile = jobMsg.AsString; string tgaFile = sceneFile.Replace(".pi", ".tga"); string jpgFile = sceneFile.Replace(".pi", ".jpg"); string sceneFilePath = Path.Combine(localStorageRootPath, sceneFile); string tgaFilePath = Path.Combine(localStorageRootPath, tgaFile); string jpgFilePath = Path.Combine(localStorageRootPath, jpgFile); // Copy the scene file to local storage sceneBlob.DownloadFile(sceneFilePath); // Run the ray tracer. string polyrayArguments = string.Format("\"{0}\" -o \"{1}\" -a 2", sceneFilePath, tgaFilePath); Process polyRayProcess = new Process(); polyRayProcess.StartInfo.FileName = Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), polyRayPath); polyRayProcess.StartInfo.Arguments = polyrayArguments; polyRayProcess.Start(); polyRayProcess.WaitForExit(); // Convert the image string dtaArguments = string.Format(" {0} /FJ /P{1}", tgaFilePath, Path.GetDirectoryName (jpgFilePath)); Process dtaProcess = new Process(); dtaProcess.StartInfo.FileName = Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), dtaPath); dtaProcess.StartInfo.Arguments = dtaArguments; dtaProcess.Start(); dtaProcess.WaitForExit(); // Upload the image to blob storage imageBlob.UploadFile(jpgFilePath); // Add a download job. downloadQueue.Add(jpgFile); // Delete the render job message jobQueue.Delete(jobMsg); Frames++; } else { Thread.Sleep(1000); } // Log the worker role activity. roleLifecycleDataSource.Alive ("CloudRayWorker", RoleLifecycleDataSource.RoleLifecycleId, Frames); } } Monitoring Worker Role Instance Lifecycle In order to get more accurate statistics about the lifecycle of the worker role instances used to render the animation data was tracked in an Azure storage table. The following class was used to track the worker role lifecycles in Azure storage. public class RoleLifecycle : TableServiceEntity { public string ServerName { get; set; } public string Status { get; set; } public DateTime StartTime { get; set; } public DateTime EndTime { get; set; } public long SecondsRunning { get; set; } public DateTime LastActiveTime { get; set; } public int Frames { get; set; } public string Comment { get; set; } public RoleLifecycle() { } public RoleLifecycle(string roleName) { PartitionKey = roleName; RowKey = Utils.GetAscendingRowKey(); Status = "Started"; StartTime = DateTime.UtcNow; LastActiveTime = StartTime; EndTime = StartTime; SecondsRunning = 0; Frames = 0; } } A new instance of this class is created and added to the storage table when the role starts. It is then updated each time the worker renders a frame to record the total number of frames rendered and the total processing time. These statistics are used be the monitoring application to determine the effectiveness of use of resources in the render farm. Rendering the Animation The Azure solution was deployed to Windows Azure with the service configuration set to 16 worker role instances. This allows for the application to be tested in the cloud environment, and the performance of the application determined. When I demo the application at conferences and user groups I often start with 16 instances, and then scale up the application to the full 256 instances. The configuration to run 16 instances is shown below. <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="CloudRay" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="1" osVersion="*"> <Role name="CloudRayWorkerRole"> <Instances count="16" /> <ConfigurationSettings> <Setting name="DataConnectionString" value="DefaultEndpointsProtocol=https;AccountName=cloudraydata;AccountKey=..." /> </ConfigurationSettings> </Role> </ServiceConfiguration> About six minutes after deploying the application the first worker roles become active and start to render the first frames of the animation. The CloudRay Monitor application displays an icon for each worker role instance, with a number indicating the number of frames that the worker role has rendered. The statistics on the left show the number of active worker roles and statistics about the render process. The render time is the time since the first worker role became active; the CPU time is the total amount of processing time used by all worker role instances to render the frames. Five minutes after the first worker role became active the last of the 16 worker roles activated. By this time the first seven worker roles had each rendered one frame of the animation. With 16 worker roles u and running it can be seen that one hour and 45 minutes CPU time has been used to render 32 frames with a render time of just under 10 minutes. At this rate it would take over 10 hours to render the 2,000 frames of the full animation. In order to complete the animation in under an hour more processing power will be required. Scaling the render farm from 16 instances to 256 instances is easy using the new management portal. The slider is set to 256 instances, and the configuration saved. We do not need to re-deploy the application, and the 16 instances that are up and running will not be affected. Alternatively, the configuration file for the Azure service could be modified to specify 256 instances. <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="CloudRay" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="1" osVersion="*"> <Role name="CloudRayWorkerRole"> <Instances count="256" /> <ConfigurationSettings> <Setting name="DataConnectionString" value="DefaultEndpointsProtocol=https;AccountName=cloudraydata;AccountKey=..." /> </ConfigurationSettings> </Role> </ServiceConfiguration> Six minutes after the new configuration has been applied 75 new worker roles have activated and are processing their first frames. Five minutes later the full configuration of 256 worker roles is up and running. We can see that the average rate of frame rendering has increased from 3 to 12 frames per minute, and that over 17 hours of CPU time has been utilized in 23 minutes. In this test the time to provision 140 worker roles was about 11 minutes, which works out at about one every five seconds. We are now half way through the rendering, with 1,000 frames complete. This has utilized just under three days of CPU time in a little over 35 minutes. The animation is now complete, with 2,000 frames rendered in a little over 52 minutes. The CPU time used by the 256 worker roles is 6 days, 7 hours and 22 minutes with an average frame rate of 38 frames per minute. The rendering of the last 1,000 frames took 16 minutes 27 seconds, which works out at a rendering rate of 60 frames per minute. The frame counts in the server instances indicate that the use of a queue to distribute the workload has been very effective in distributing the load across the 256 worker role instances. The first 16 instances that were deployed first have rendered between 11 and 13 frames each, whilst the 240 instances that were added when the application was scaled have rendered between 6 and 9 frames each. Completed Animation I’ve uploaded the completed animation to YouTube, a low resolution preview is shown below. Pin Board Animation Created using Windows Kinect and 256 Windows Azure Worker Roles The animation can be viewed in 1280x720 resolution at the following link: http://www.youtube.com/watch?v=n5jy6bvSxWc Effective Use of Resources According to the CloudRay monitor statistics the animation took 6 days, 7 hours and 22 minutes CPU to render, this works out at 152 hours of compute time, rounded up to the nearest hour. As the usage for the worker role instances are billed for the full hour, it may have been possible to render the animation using fewer than 256 worker roles. When deciding the optimal usage of resources, the time required to provision and start the worker roles must also be considered. In the demo I started with 16 worker roles, and then scaled the application to 256 worker roles. It would have been more optimal to start the application with maybe 200 worker roles, and utilized the full hour that I was being billed for. This would, however, have prevented showing the ease of scalability of the application. The new management portal displays the CPU usage across the worker roles in the deployment. The average CPU usage across all instances is 93.27%, with over 99% used when all the instances are up and running. This shows that the worker role resources are being used very effectively. Grid Computing Scenarios Although I am using this scenario for a hobby project, there are many scenarios where a large amount of compute power is required for a short period of time. Windows Azure provides a great platform for developing these types of grid computing applications, and can work out very cost effective. · Windows Azure can provide massive compute power, on demand, in a matter of minutes. · The use of queues to manage the load balancing of jobs between role instances is a simple and effective solution. · Using a cloud-computing platform like Windows Azure allows proof-of-concept scenarios to be tested and evaluated on a very low budget. · No charges for inbound data transfer makes the uploading of large data sets to Windows Azure Storage services cost effective. (Transaction charges still apply.) Tips for using Windows Azure for Grid Computing Scenarios I found the implementation of a render farm using Windows Azure a fairly simple scenario to implement. I was impressed by ease of scalability that Azure provides, and by the short time that the application took to scale from 16 to 256 worker role instances. In this case it was around 13 minutes, in other tests it took between 10 and 20 minutes. The following tips may be useful when implementing a grid computing project in Windows Azure. · Using an Azure Storage queue to load-balance the units of work across multiple worker roles is simple and very effective. The design I have used in this scenario could easily scale to many thousands of worker role instances. · Windows Azure accounts are typically limited to 20 cores. If you need to use more than this, a call to support and a credit card check will be required. · Be aware of how the billing model works. You will be charged for worker role instances for the full clock our in which the instance is deployed. Schedule the workload to start just after the clock hour has started. · Monitor the utilization of the resources you are provisioning, ensure that you are not paying for worker roles that are idle. · If you are deploying third party applications to worker roles, you may well run into licensing issues. Purchasing software licenses on a per-processor basis when using hundreds of processors for a short time period would not be cost effective. · Third party software may also require installation onto the worker roles, which can be accomplished using start-up tasks. Bear in mind that adding a startup task and possible re-boot will add to the time required for the worker role instance to start and activate. An alternative may be to use a prepared VM and use VM roles. · Consider using the Windows Azure Autoscaling Application Block (WASABi) to autoscale the worker roles in your application. When using a large number of worker roles, the utilization must be carefully monitored, if the scaling algorithms are not optimal it could get very expensive!

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CodePlex Daily Summary for Sunday, August 10, 2014

CodePlex Daily Summary for Sunday, August 10, 2014Popular ReleasesWinForms MVP: WinForms MVP v1.0.1008.2014: Issues Fixed Issue 1 New Added MessageBus and AppState features. Added tests in support of the MessageBus and AppState features Added dependency injection support for Ninject. Added tests in support of the NinjectPresenterFactory.WP8 Native Access Webserver: Version alpha 0.5.3: Figured I should post a newer version. This build includes pretty broad registry browsing (especially if you can use the AllCapabilities version) and (in the AC version) also fairly broad file system access. It also includes the ability to download .REG files. There have been tons of bugfixes and performance improvements as well, plus a slightly better UI in both the app and the web interface. For more info, please read the forum post here: http://forum.xda-developers.com/showthread.php?t=23...ClosedXML - The easy way to OpenXML: ClosedXML 0.74.0: Many updates. See history.SEToolbox: SEToolbox 01.042.019 Release 1: Added RadioAntenna broadcast name to ship name detail. Added two additional columns for Asteroid material generation for Asteroid Fields. Added Mass and Block number columns to main display. Added Ellipsis to some columns on main display to reduce name confusion. Added correct SE version number in file when saving. Re-added in reattaching Motor when drag/dropping or importing ships (KeenSH have added RotorEntityId back in after removing it months ago). Added option to export and r...Instant Beautiful Browsing: IBB 14.3 Alpha: An alpha release of IBB. After 3 years of the last release this version is made from scratch, with tons of new features like: Make your own IBB aps. HTML 5. Better UI. Extreme Windows 8 resemblance. Photos. Store. Movement TONS of times smother compared to previous versions. Remember that this is AN ALPHA release, I hope I will have "IBB 14" finished by December. The documentation on how to create a new application for IBB will come next monthjQuery List DragSort: jQuery List DragSort 0.5.2: Fixed scrollContainer removing deprecated use of $.browser so should now work with latest version of jQuery. Added the ability to return false in dragEnd to revert sort order Project changes Added nuget package for dragsort https://www.nuget.org/packages/dragsort Converted repository from SVN to MercurialCRM 2013 One Click Navigation: CRM2013OneClickNavigation_1_0_0_4_managed.zip: Fixed some minor issues and added support for the following languages Spanish German French Italian Portuguese Russian Arabic Chinese Japanese Hindi Hebrew Korean Polish ThaiBraintree Client Library: Braintree 2.32.0: Allow credit card verification options to be passed outside of the nonce for PaymentMethod.create Allow billingaddress parameters and billingaddress_id to be passed outside of the nonce for PaymentMethod.create Add Subscriptions to paypal accounts Add PaymentMethod.update Add failonduplicatepaymentmethod option to PaymentMethod.create Add support for dispute webhooksThe Mario Kart 8 App: V1.0.2.1: First Codeplex release. WINDOWS INSTALLER ONLYAspose Java for Docx4j: Aspose.Words vs Docx4j - v 1.0: Release contain the Code Comparison for Features in Docx4j SDK and Aspose.Words What's New ?Following Examples: Accessing Document Properties Add Bookmarks Convert to Formats Delete Bookmarks Working with Comments Feedback and Suggestions Many more examples are available at Aspose Docs. Raise your queries and suggest more examples via Aspose Forums or via this social coding site.File System Security PowerShell Module: NTFSSecurity 2.4.1: Add-Access and Remove-Access now take multiple accoutsYourSqlDba: YourSqlDba 5.2.1.: This version improves alert message that comes a while after you install the script. First it says to get it from YourSqlDba.CodePlex.com If you don't want to update now, just-rerun the script from your installed version. To get actual version running just execute install.PrintVersionInfo. . You can go to source code / history and click on change set 72957 to see changes in the script.Manipulator: Manipulator: manipulatorXNB filetype plugin for Paint.NET: Paint.NET XNB plugin v0.4.0.0: CHANGELOG Reverted old incomplete changes. Updated library for compatibility with Paint .NET 4. Updated project to NET 4.5. Updated version to 0.4.0.0. INSTALLATION INSTRUCTIONS Extract the ZIP file to your Paint.NET\FileTypes folder.EdiFabric: Release 4.1: Changed MessageContextWix# (WixSharp) - managed interface for WiX: Release 1.0.0.0: Release 1.0.0.0 Custom UI Custom MSI Dialog Custom CLR Dialog External UIMath.NET Numerics: Math.NET Numerics v3.2.0: Linear Algebra: Vector.Map2 (map2 in F#), storage-optimized Linear Algebra: fix RemoveColumn/Row early index bound check (was not strict enough) Statistics: Entropy ~Jeff Mastry Interpolation: use Array.BinarySearch instead of local implementation ~Candy Chiu Resources: fix a corrupted exception message string Portable Build: support .Net 4.0 as well by using profile 328 instead of 344. .Net 3.5: F# extensions now support .Net 3.5 as well .Net 3.5: NuGet package now contains pro...Virto Commerce Enterprise Open Source eCommerce Platform (asp.net mvc): Virto Commerce 1.11: Virto Commerce Community Edition version 1.11. To install the SDK package, please refer to SDK getting started documentation To configure source code package, please refer to Source code getting started documentation This release includes many bug fixes and minor improvements. More details about this release can be found on our blog at http://blog.virtocommerce.com.BoxStarter: Boxstarter 2.4.80: Running the Setup.bat file will install Chocolatey if not present and then install the Boxstarter modules.ProjkyAddin ssms addin script shortcut ssmsaddin: projkyaddin source code and msi files.: projkyaddin source code and msi files.New ProjectsBolos: BolosBWQS - The BitWise Query Service: Generic object queries with a bitwise syntax.DocX Razor: A DocX scaffolding engine with Razor syntaxJQuery Simple Logger: Its a very simple jQuery extension for logging client side events. There are four levels of logging: Error, Warning, Info, Debug ???????: ???????QQ:2281595668，?????，????，????　　?????????????????????，??1998?7??????，??????????，?????????，?????????????，????????????????????????. ????????????????????，????????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。???????，??????????????????????。????????，????????????，?????????: ???????????: ?????QQ:2281595668，?????，????，????。????????????????????????，????????????，??????98???????????，????，??????????，?????????. 　　?????????,????????????????，????????????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、???????: ???????????: ?????QQ：2281595668，?????，????，????。???????????????????，??1998?7??????，??????????，?????????，?????????????，??????????????????????. ????????????????????，????????????????: ????????????: ???????????: ?????QQ：2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，???????: ??????QQ:2281595668，?????，????，????。??????????????????，????????。????????????????、???????。??????????????。?????????????????,??????,??????,??????,??????????????，????????: ??????QQ:2281595668，?????，????，????　　????????????????????，????????。????????????????、???????。??????????????。???????????????????,??????,??????,??????,??????????????????: ???????????: ??????????: ?????QQ：2281595668，?????，????，????。???????????????????，??1998?7??????，??????????，?????????，?????????????，??????????????????????. ????????????????????，????????????????: ??????QQ:2281595668，?????，????，????　　 ????????????????????，??1998?7??????，??????????，??????? ????????，?????????????， ???????????????????????. ???????????????????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ????????????: ??????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，????????????，????，??“??????”????????: ??????QQ:2281595668，?????，????，????。??????????????????????????，????????????!??????????????????????????????????????????、???????、????、??????、??????????。???????????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、???????: ???????????: ?????QQ:2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,?????: ?????QQ：2281595668，?????，????，????。　　??????98???????????，???????????????????，????????????，????，??????????，?????????，?????????,????????????????，???????????，??????????: ??????????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“???????????: ?????QQ：2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，?????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、???????????????: ????????????: ???????????: ?????QQ：2281595668，?????，????，????。???????????????????，??1998?7??????，??????????，?????????，?????????????，??????????????????????. ????????????????????，???????????????: ?????QQ：2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,?????: ?????QQ：2281595668，?????，????，????。　　??????98???????????，???????????????????，????????????，????，??????????，?????????，?????????,????????????????，???????????，??????????: ?????QQ:2281595668，?????，????，????。?????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，???????????，???????: ??????????????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????????: ?????QQ：2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;??????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、??????????????: ???????????: ????????????: ????????????: ????????????: ????????????QQ:2281595668，?????，????，????　　???????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，????????????????????????: ?????????????: ???????QQ：2281595668，?????，????，????。???????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，??????????????: ??????QQ：2281595668，?????，????，????。???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????????: ?????QQ：2281595668，?????，????，????。??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，????????????????????????????????: ?????QQ:2281595668，?????，????，????。????????????????????????，????????????，??????98???????????，????，??????????，?????????. 　　?????????,????????????????，????????????????: ?????QQ:2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,?????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、??????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，?????: ?????QQ：2281595668，?????，????，????。???????????????????，??1998?7??????，??????????，?????????，?????????????，??????????????????????. ????????????????????，???????????????: ?????QQ:2281595668，?????，????，????　　????????????????????，????????。????????????????、???????。??????????????。???????????????????,??????,??????,??????,??????????????????: ?????QQ：2281595668，?????，????，????。??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，?????????????????????????????????: ???????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ???????????: ?????QQ：2281595668，?????，????，????。??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，????????????????????????????????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，??????: ?????QQ：2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;??????: ?????QQ:2281595668，?????，????，????。????????????????????????，????????????，??????98???????????，????，??????????，?????????. 　　?????????,????????????????，?????????????????: ??????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????? ????????????: ?????????????QQ:2281595668，?????，????，????　　???????????????????，????????????，???????98???????????，????，??????????，?????????. 　　?????????,????????????????，???????????: ?????QQ:2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;??????: ?????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”?????????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。???????，??????????????????????。????????，????????????，????????: ?????QQ：2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，???????: ??????QQ:2281595668，?????，????，????。?????????????????????????，????????????，???????98???????????，????，??????????，?????????. 　　?????????,????????????????，?????????????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，??????: ?????QQ:2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、??????: ??????????: ?????QQ：2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,??????: ???????????: ?????QQ：2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，??????: ?????QQ:2281595668，?????，????，????　　???????????????????，????????????，??????98???????????，????，??????????，?????????. 　　?????????,????????????????，???????????，????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、??????????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ???????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、???????: ?????????????: ??????????????QQ:2281595668，?????，????，????　　?????????????????????，??1998?7??????，??????????，?????????，?????????????，????????????????????????. ??????????????????????: ???????????: ????????????: ??????QQ:2281595668，?????，????，????　　???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;???????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”???? ?????，???????????????: ?????QQ:2281595668，?????，????，????　　??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;?????: ?????QQ:2281595668，?????，????，????。?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、??????????。??????????????????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”???? ?????，???????????????: ??????????: ?????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”??????????: ??????QQ:2281595668，?????，????，????。???????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”???? ?????，????????????????: ????????????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????: ?????QQ：2281595668，?????，????，????。?????????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????，????????: ?????QQ：2281595668，?????，????，????。　　??????98???????????，???????????????????，????????????，????，??????????，?????????，?????????,????????????????，???????????，??????????: ?????QQ:2281595668，?????，????，????　　??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、??????: ??????QQ:2281595668，?????，????，????　　???????????????????，????????????，???????98???????????，????，??????????，?????????. 　　?????????,????????????????，???????????，???????: ????????????: ?????????????: hhhtbjzjgh??????: ??????QQ：2281595668，?????，????，????。??????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，???????????????: ?????QQ:2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、??????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，???????: ???????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，?????: ?????QQ:2281595668，?????，????，????。　　?????????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????，???????: ??????QQ:2281595668，?????，????，????。??????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，????????????????: ??????QQ:2281595668，?????，????，????　　???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????????: ??????QQ:2281595668，?????，????，????　　???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;???????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，???????: ??????QQ：2281595668，?????，????，????。???????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，??????????????????????????????: ?????QQ：2281595668，?????，????，????。?????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，???????????，??????: ??????QQ:2281595668，?????，????，????。???????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????????: ?????QQ:2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;???????: ??????QQ:2281595668，?????，????，????。???????????????，?????????????????????，????????????????????????!??????????????????????????????????????????????、?????????、??????????: ????????????QQ:2281595668，?????，????，????　　???????????????，?????????????????????，????????????????????????!??????????????????????????????????????????????、?????????????: ???????????: ?????QQ:2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,?????: ?????QQ：2281595668，?????，????，????。?????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，???????????，?????: ?????QQ：2281595668，?????，????，????。???????????????????，??1998?7??????，??????????，?????????，?????????????，??????????????????????. ????????????????????，???????????????: ?????QQ:2281595668，?????，????，????　　??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，???????????????????????????????: tybjza?????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”???? ?????，????????????????: ??????QQ:2281595668，?????，????，????。　　??????????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，??????????????????: ?????QQ:2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,????????: ????????QQ:2281595668，?????，????，????　　?????????????????????????????,?????????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;??????: ?????QQ：2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;??????: ?????QQ：2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，?????: ?????QQ：2281595668，?????，????，????。?????????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????，????????: ?????QQ：2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,??????: ????????????QQ:2281595668，?????，????，????　　???????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，???????????????????????: ?????QQ:2281595668，?????，????，????。?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、??????????。??????????????????: ?????QQ:2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,?????: ?????QQ：2281595668，?????，????，????。??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，????????????????????????????????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。???????，??????????????????????。????????，????????????，????????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? 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????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????? ?????????: ?????QQ:2281595668，?????，????，????　　???????????????????，????????????，??????98???????????，????，??????????，?????????. 　　?????????,????????????????，???????????，????????: ??????????: ?????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”?????????: ?????QQ：2281595668，?????，????，????。???????????????????，??1998?7??????，??????????，?????????，?????????????，??????????????????????. ????????????????????，???????????????: ?????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????? ?????，??????: ???????????: ?????QQ：2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，???????: ????????????: ??????QQ:2281595668，?????，????，????　　????????????????????，????????。????????????????、???????。??????????????。???????????????????,??????,??????,??????,??????????????????: ??????QQ:2281595668，?????，????，????。???????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，???????????????: ??????QQ:2281595668，?????，????，????　　????????????????????，??1998?7??????，??????????，?????????，?????????????，???????????????????????. ????????????????????，???????????: ?????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”?????????: ?????????????????: ??????????????????: ????????????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，?????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ???????????: ?????QQ：2281595668，?????，????，????。?????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，???????????，??????: ????????????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，????????????，????，??“????????: ?????QQ:2281595668，?????，????，????。?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、??????????。??????????????????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”???? ?????，???????????????: ?????QQ：2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,??????: ????????????: ??????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????? ??????????: ?????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????? ?????，?????: ?????QQ:2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、???????: ??????QQ:2281595668，?????，????，????　　???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????????: ??????QQ:2281595668，?????，????，????　　???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????????: ??????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????? ??????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、???????????????: ??????QQ:2281595668，?????，????，????。???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;?????????: ????????????: ???????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，?????: ?????QQ：2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,?????: ??????????: ????????????: ????????????: ??????????: ????? QQ:2281595668，?????，????，????。????? ?????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，???????????????: ??????QQ:2281595668，?????，????，????。????????????????????，??????????????，????，?????????????????????，??????。????????，??????????????????????。????????，????????????，??????: ??????QQ:2281595668，?????，????，????　　???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;???????: ?????QQ:2281595668，?????，????，????。?????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，???????????，??????: ??????QQ:2281595668，?????，????，????　　???????????????????，????????????，???????98???????????，????，??????????，?????????. 　　?????????,????????????????，???????????，??????: ?????QQ：2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，???????: ??????QQ:2281595668，?????，????，????。????????????????????，??????????????，????，?????????????????????，??????。????????，??????????????????????。????????，????????????，????????: ????????QQ:2281595668，?????，????，????　　????????????????????，????????。????????????????、???????。??????????????。???????????????????,??????,??????,??????,??????????????????: ????????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，??????????????，????，??“???????????: ???????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ????????????: ??????QQ：2281595668，?????，????，????。????????????????????，??1998?7??????，??????????，?????????，?????????????，???????????????????????. ????????????????????，?????????????: ???????????: ?????QQ:2281595668，?????，????，????　　??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，???????????????????????????????: ?????QQ：2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;???????: ????????????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，??????????????: ??????QQ:2281595668，?????，????，????。??????????????????，????????。????????????????、???????。??????????????。?????????????????,??????,??????,??????,??????????????，????????: ????????????: ????????????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，????????????，????，??“????????: ???????????: ?????????????: ???????QQ:2281595668，?????，????，????。????????????????，?????????????????????，?????????????????????????!???????????????????????????????????????????????、?????????、??????: ??????QQ:2281595668，?????，????，????。???????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ???????????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。???????，??????????????????????。????????，????????????，?????????: ??????QQ:2281595668，?????，????，????。??????????????????????????，????????????!??????????????????????????????????????????、???????、????、??????、??????????。????????????????: ??????QQ:2281595668，?????，????，????。????????????????????，??????????????，????，?????????????????????，??????。????????，??????????????????????。????????，????????????，??????: ??????QQ:2281595668，?????，????，????。?????????????????????????，????????????，???????98???????????，????，??????????，?????????. 　　?????????,????????????????，??????????????: ????????????: ???????????: ?????QQ:2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;???????: ????????????: ????????????: ??????QQ:2281595668，?????，????，????　　???????????????????，????????????，???????98???????????，????，??????????，?????????. 　　?????????,????????????????，???????????，???????: ??????QQ:2281595668，?????，????，????。???????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，???????????????: ??????QQ:2281595668，?????，????，????。???????????????，?????????????????????，????????????????????????!??????????????????????????????????????????????、?????????、?????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、??????????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、???????????????: ??????QQ:2281595668，?????，????，????。???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????????: ?????QQ:2281595668，?????，????，????　　????????????????????，????????。????????????????、???????。??????????????。???????????????????,??????,??????,??????,??????????????????: ?????QQ:2281595668，?????，????，????。　　?????????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????，???????: ??????QQ:2281595668，?????，????，????。??????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，????????????????: ???????????: ?????QQ：2281595668，?????，????，????。　　??????98???????????，???????????????????，????????????，????，??????????，?????????，?????????,????????????????，???????????，??????????: ?????QQ：2281595668，?????，????，????。??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，?????????????????????????????????: ????????????: ????????????: ??????QQ:2281595668，?????，????，????。????????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，????????????: ????????????: ???????????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”???? ?????，???????????????: ?????QQ:2281595668，?????，????，????　　??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;?????: ?????QQ：2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ??????

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Images missing after moving Django to new server

- by miszczu

I'm moving Django project to new server. I'm newbie in Django, and I don't know where should be upload folder. There are all images which should be displayed on website. In config file I haven't seen upload folder I could specify, so I'm guessing it always should be the same location for django projects or I just can't find it. Locations are saved in database. When I've put uploaded files into media folder, so url was like domain.co.uk/media/upload/media/images/year/month/day/image_name.ext and the same is on the old website, images on website ware still missing. All images are visible if I put url by hand, but django doesn't seems to see files. Also I check django log file: 2012-05-30 09:13:33,393 ERROR render: Thumbnail tag failed: [in /usr/lib/python2.6/site-packages/sorl_thumbnail-11.12-py2.6.egg/sorl/thumbnail/templatetags/thumbnail.py (line 49)] Traceback (most recent call last): File "/usr/lib/python2.6/site-packages/sorl_thumbnail-11.12-py2.6.egg/sorl/thumbnail/templatetags/thumbnail.py", line 45, in render return self._render(context) File "/usr/lib/python2.6/site-packages/sorl_thumbnail-11.12-py2.6.egg/sorl/thumbnail/templatetags/thumbnail.py", line 97, in _render file_, geometry, **options File "/usr/lib/python2.6/site-packages/sorl_thumbnail-11.12-py2.6.egg/sorl/thumbnail/base.py", line 50, in get_thumbnail cached = default.kvstore.get(thumbnail) File "/usr/lib/python2.6/site-packages/sorl_thumbnail-11.12-py2.6.egg/sorl/thumbnail/kvstores/base.py", line 25, in get return self._get(image_file.key) File "/usr/lib/python2.6/site-packages/sorl_thumbnail-11.12-py2.6.egg/sorl/thumbnail/kvstores/base.py", line 123, in _get value = self._get_raw(add_prefix(key, identity)) File "/usr/lib/python2.6/site-packages/sorl_thumbnail-11.12-py2.6.egg/sorl/thumbnail/kvstores/cached_db_kvstore.py", line 26, in _get_raw value = KVStoreModel.objects.get(key=key).value File "/usr/lib/python2.6/site-packages/django/db/models/manager.py", line 132, in get return self.get_query_set().get(*args, **kwargs) File "/usr/lib/python2.6/site-packages/django/db/models/query.py", line 344, in get num = len(clone) File "/usr/lib/python2.6/site-packages/django/db/models/query.py", line 82, in __len__ self._result_cache = list(self.iterator()) File "/usr/lib/python2.6/site-packages/django/db/models/query.py", line 273, in iterator for row in compiler.results_iter(): File "/usr/lib/python2.6/site-packages/django/db/models/sql/compiler.py", line 680, in results_iter for rows in self.execute_sql(MULTI): File "/usr/lib/python2.6/site-packages/django/db/models/sql/compiler.py", line 735, in execute_sql cursor.execute(sql, params) File "/usr/lib/python2.6/site-packages/django/db/backends/util.py", line 34, in execute return self.cursor.execute(sql, params) File "/usr/lib/python2.6/site-packages/django/db/backends/mysql/base.py", line 86, in execute return self.cursor.execute(query, args) File "/usr/lib64/python2.6/site-packages/MySQLdb/cursors.py", line 174, in execute self.errorhandler(self, exc, value) File "/usr/lib64/python2.6/site-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler raise errorclass, errorvalue DatabaseError: (1146, "Table 'thumbnail_kvstore' doesn't exist") 2012-05-30 09:13:33,396 DEBUG execute: (0.000) SELECT `freetext_freetext`.`id`, `freetext_freetext`.`key`, `freetext_freetext`.`content`, `freetext_freetext`.`active` FROM `freetext_freetext` WHERE (`freetext_freetext`.`active` = True AND `freetext_freetext`.`key` = office-closed-message ); args=(True, u'office-closed-message') [in /usr/lib/python2.6/site-packages/django/db/backends/util.py (line 44)] 2012-05-30 09:13:33,399 DEBUG execute: (0.000) SELECT `menus_menu`.`id`, `menus_menu`.`name`, `menus_menu`.`slug`, `menus_menu`.`base_url`, `menus_menu`.`description`, `menus_menu`.`enabled` FROM `menus_menu` WHERE (`menus_menu`.`enabled` = True AND `menus_menu`.`slug` = about ); args=(True, u'about') [in /usr/lib/python2.6/site-packages/django/db/backends/util.py (line 44)] 2012-05-30 09:13:33,401 DEBUG execute: (0.000) SELECT `menus_menuitem`.`id`, `menus_menuitem`.`menu_id`, `menus_menuitem`.`title`, `menus_menuitem`.`url`, `menus_menuitem`.`order` FROM `menus_menuitem` INNER JOIN `menus_menu` ON (`menus_menuitem`.`menu_id` = `menus_menu`.`id`) WHERE `menus_menu`.`slug` = about ORDER BY `menus_menuitem`.`order` ASC; args=(u'about',) [in /usr/lib/python2.6/site-packages/django/db/backends/util.py (line 44)] 2012-05-30 09:13:33,404 DEBUG execute: (0.000) SELECT `freetext_freetext`.`id`, `freetext_freetext`.`key`, `freetext_freetext`.`content`, `freetext_freetext`.`active` FROM `freetext_freetext` WHERE (`freetext_freetext`.`active` = True AND `freetext_freetext`.`key` = contactdetails-footer ); args=(True, u'contactdetails-footer') [in /usr/lib/python2.6/site-packages/django/db/backends/util.py (line 44)] I checked database and there is no table calls thumbnail_kvstore, but I have database backup, and in backup files this table doesn't exist. All uploaded files I get are in media/uploads/media/. Also I'm getting errors on some pages: Syntax error. Expected: ``thumbnail source geometry [key1=val1 key2=val2...] as var`` /usr/lib/python2.6/site-packages/sorl_thumbnail-11.12-py2.6.egg/sorl/thumbnail/templatetags/thumbnail.py in __init__, line 72 In template /var/www/vhosts/domain.co.uk/sites/apps/shop/products/templates/products/product_detail.html, error at line 34 {% thumbnail image.file "800x700" detail as zoom %} Maybe some modules I install are not in the right version. Dont know how to fix it. Im using, CentOS 6, mod_wsgi, apache, python 2.6. Update 1.0: On the old server was Django 1.3, on the new one is Django 1.3.1 Update 1.1: I this i know where is the problem. I tried python manage.py syncdb and this is output: Syncing... Creating tables ... The following content types are stale and need to be deleted: orders | ordercontact Any objects related to these content types by a foreign key will also be deleted. Are you sure you want to delete these content types? If you're unsure, answer 'no'. Type 'yes' to continue, or 'no' to cancel: no Installing custom SQL ... Installing indexes ... No fixtures found. Synced: > django.contrib.auth > django.contrib.contenttypes > django.contrib.sessions > django.contrib.sites > django.contrib.messages > django.contrib.admin > django.contrib.admindocs > django.contrib.markup > django.contrib.sitemaps > django.contrib.redirects > django_filters > freetext > sorl.thumbnail > django_extensions > south > currencies > pagination > tagging > honeypot > core > faq > logentry > menus > news > shop > shop.cart > shop.orders Not synced (use migrations): - dbtemplates - contactform - links - media - pages - popularity - testimonials - shop.brands - shop.collections - shop.discount - shop.pricing - shop.product_types - shop.products - shop.shipping - shop.tax (use ./manage.py migrate to migrate these) Next I run python manage.py migrate, and thats what i get: Running migrations for dbtemplates: - Migrating forwards to 0002_auto__del_unique_template_name. > dbtemplates:0001_initial ! Error found during real run of migration! Aborting. ! Since you have a database that does not support running ! schema-altering statements in transactions, we have had ! to leave it in an interim state between migrations. ! You *might* be able to recover with: = DROP TABLE `django_template` CASCADE; [] = DROP TABLE `django_template_sites` CASCADE; [] ! The South developers regret this has happened, and would ! like to gently persuade you to consider a slightly ! easier-to-deal-with DBMS. ! NOTE: The error which caused the migration to fail is further up. Traceback (most recent call last): File "manage.py", line 13, in <module> execute_manager(settings) File "/usr/lib/python2.6/site-packages/django/core/management/__init__.py", line 438, in execute_manager utility.execute() File "/usr/lib/python2.6/site-packages/django/core/management/__init__.py", line 379, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "/usr/lib/python2.6/site-packages/django/core/management/base.py", line 191, in run_from_argv self.execute(*args, **options.__dict__) File "/usr/lib/python2.6/site-packages/django/core/management/base.py", line 220, in execute output = self.handle(*args, **options) File "/usr/lib/python2.6/site-packages/South-0.7.3-py2.6.egg/south/management/commands/migrate.py", line 105, in handle ignore_ghosts = ignore_ghosts, File "/usr/lib/python2.6/site-packages/South-0.7.3-py2.6.egg/south/migration/__init__.py", line 191, in migrate_app success = migrator.migrate_many(target, workplan, database) File "/usr/lib/python2.6/site-packages/South-0.7.3-py2.6.egg/south/migration/migrators.py", line 221, in migrate_many result = migrator.__class__.migrate_many(migrator, target, migrations, database) File "/usr/lib/python2.6/site-packages/South-0.7.3-py2.6.egg/south/migration/migrators.py", line 292, in migrate_many result = self.migrate(migration, database) File "/usr/lib/python2.6/site-packages/South-0.7.3-py2.6.egg/south/migration/migrators.py", line 125, in migrate result = self.run(migration) File "/usr/lib/python2.6/site-packages/South-0.7.3-py2.6.egg/south/migration/migrators.py", line 99, in run return self.run_migration(migration) File "/usr/lib/python2.6/site-packages/South-0.7.3-py2.6.egg/south/migration/migrators.py", line 81, in run_migration migration_function() File "/usr/lib/python2.6/site-packages/South-0.7.3-py2.6.egg/south/migration/migrators.py", line 57, in <lambda> return (lambda: direction(orm)) File "/usr/lib/python2.6/site-packages/django_dbtemplates-1.3-py2.6.egg/dbtemplates/migrations/0001_initial.py", line 18, in forwards ('last_changed', self.gf('django.db.models.fields.DateTimeField')(default=datetime.datetime.now)), File "/usr/lib/python2.6/site-packages/South-0.7.3-py2.6.egg/south/db/generic.py", line 226, in create_table ', '.join([col for col in columns if col]), File "/usr/lib/python2.6/site-packages/South-0.7.3-py2.6.egg/south/db/generic.py", line 150, in execute cursor.execute(sql, params) File "/usr/lib/python2.6/site-packages/django/db/backends/util.py", line 34, in execute return self.cursor.execute(sql, params) File "/usr/lib/python2.6/site-packages/django/db/backends/mysql/base.py", line 86, in execute return self.cursor.execute(query, args) File "/usr/lib64/python2.6/site-packages/MySQLdb/cursors.py", line 174, in execute self.errorhandler(self, exc, value) File "/usr/lib64/python2.6/site-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler raise errorclass, errorvalue _mysql_exceptions.OperationalError: (1050, "Table 'django_template' already exists") Also i run python manage.py migrate --list, and uotput is: dbtemplates (*) 0001_initial (*) 0002_auto__del_unique_template_name contactform (*) 0001_initial (*) 0002_auto__add_callback (*) 0003_auto__add_field_callback_notes (*) 0004_auto__add_field_callback_is_closed__add_field_callback_closed (*) 0005_auto__add_field_callback_url (*) 0006_auto__add_contact (*) 0007_auto__add_field_contact_category (*) 0008_auto__add_field_contact_url links (*) 0001_initial (*) 0002_auto__add_field_category_enabled__add_field_category_order media (*) 0001_initial (*) 0002_auto__del_field_image_external_url__add_field_image_link_url__del_fiel (*) 0003_add_model_FileAttachment (*) 0004_auto__chg_field_file_slug__chg_field_image_slug (*) 0005_auto__chg_field_image_file (*) 0006_auto__chg_field_file_file pages (*) 0001_initial (*) 0002_auto__chg_field_page_meta_description__chg_field_page_meta_title__chg_ (*) 0003_auto__add_field_page_show_in_sitemap (*) 0004_auto__add_field_page_changefreq__add_field_page_priority popularity (*) 0001_initial testimonials (*) 0001_initial (*) 0002_auto__add_field_testimonial_is_featured brands (*) 0001_initial (*) 0002_auto__add_field_brand_template (*) 0003_auto__chg_field_brand_meta_description__chg_field_brand_meta_title__ch (*) 0004_auto__add_field_brand_url (*) 0005_auto__del_field_brand_image__add_field_brand_logo collections (*) 0001_initial (*) 0002_auto__add_field_collection_discount (*) 0003_auto__chg_field_collection_meta_description__chg_field_collection_meta (*) 0004_auto__add_field_collection_is_featured (*) 0005_auto__add_field_collection_order discount (*) 0001_initial (*) 0002_added_field_discount_description (*) 0003_auto__add_field_discountvoucher_automatic (*) 0004_auto__add_field_discountvoucher_collection (*) 0005_auto__del_field_discountvoucher_collection (*) 0006_auto__chg_field_discountvoucher_expiry_date pricing (*) 0001_initial (*) 0002_auto__add_pricingrule product_types (*) 0001_initial (*) 0002_auto__add_field_producttype_meta_title__add_field_producttype_meta_des (*) 0003_auto__add_field_producttype_summary__add_field_producttype_description products (*) 0001_initial (*) 0002_auto__del_field_product_is_featured (*) 0003_auto__chg_field_product_meta_keywords__chg_field_product_meta_descript (*) 0004_auto shipping (*) 0001_initial (*) 0002_auto__add_field_shippingmethod_includes_tax__add_field_shippingmethod_ (*) 0003_auto__add_field_shippingmethod_order (*) 0004_auto__del_field_shippingmethod_tax_rate__del_field_shippingmethod_incl (*) 0005_auto__del_field_shippingrule_enabled tax (*) 0001_initial (*) 0002_auto__add_field_taxrate_internal_name (*) 0003_initial_internal_names (*) 0004_auto__add_unique_taxrate_internal_name (*) 0005_force_unique_taxrate_name (*) 0006_auto__add_unique_taxrate_name After that some images source were something like this: src="cache/1e/bd/1ebd719910aa843238028edd5fe49e71.jpg" Is any1 could help me with syncdb pledase?

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Why isn't my operator overloading working properly?

- by Mithrax

I have the following Polynomial class I'm working on: #include <iostream> using namespace std; class Polynomial { //define private member functions private: int coef[100]; // array of coefficients // coef[0] would hold all coefficients of x^0 // coef[1] would hold all x^1 // coef[n] = x^n ... int deg; // degree of polynomial (0 for the zero polynomial) //define public member functions public: Polynomial::Polynomial() //default constructor { for ( int i = 0; i < 100; i++ ) { coef[i] = 0; } } void set ( int a , int b ) //setter function { //coef = new Polynomial[b+1]; coef[b] = a; deg = degree(); } int degree() { int d = 0; for ( int i = 0; i < 100; i++ ) if ( coef[i] != 0 ) d = i; return d; } void print() { for ( int i = 99; i >= 0; i-- ) { if ( coef[i] != 0 ) { cout << coef[i] << "x^" << i << " "; } } } // use Horner's method to compute and return the polynomial evaluated at x int evaluate ( int x ) { int p = 0; for ( int i = deg; i >= 0; i-- ) p = coef[i] + ( x * p ); return p; } // differentiate this polynomial and return it Polynomial differentiate() { if ( deg == 0 ) { Polynomial t; t.set ( 0, 0 ); return t; } Polynomial deriv;// = new Polynomial ( 0, deg - 1 ); deriv.deg = deg - 1; for ( int i = 0; i < deg; i++ ) deriv.coef[i] = ( i + 1 ) * coef[i + 1]; return deriv; } Polynomial Polynomial::operator + ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) c.coef[i] += a.coef[i]; for ( int i = 0; i <= b.deg; i++ ) c.coef[i] += b.coef[i]; c.deg = c.degree(); return c; } Polynomial Polynomial::operator += ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) c.coef[i] += a.coef[i]; for ( int i = 0; i <= b.deg; i++ ) c.coef[i] += b.coef[i]; c.deg = c.degree(); for ( int i = 0; i < 100; i++) a.coef[i] = c.coef[i]; a.deg = a.degree(); return a; } Polynomial Polynomial::operator -= ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) c.coef[i] += a.coef[i]; for ( int i = 0; i <= b.deg; i++ ) c.coef[i] -= b.coef[i]; c.deg = c.degree(); for ( int i = 0; i < 100; i++) a.coef[i] = c.coef[i]; a.deg = a.degree(); return a; } Polynomial Polynomial::operator *= ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) for ( int j = 0; j <= b.deg; j++ ) c.coef[i+j] += ( a.coef[i] * b.coef[j] ); c.deg = c.degree(); for ( int i = 0; i < 100; i++) a.coef[i] = c.coef[i]; a.deg = a.degree(); return a; } Polynomial Polynomial::operator - ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) c.coef[i] += a.coef[i]; for ( int i = 0; i <= b.deg; i++ ) c.coef[i] -= b.coef[i]; c.deg = c.degree(); return c; } Polynomial Polynomial::operator * ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) for ( int j = 0; j <= b.deg; j++ ) c.coef[i+j] += ( a.coef[i] * b.coef[j] ); c.deg = c.degree(); return c; } }; int main() { Polynomial a, b, c, d; a.set ( 7, 4 ); //7x^4 a.set ( 1, 2 ); //x^2 b.set ( 6, 3 ); //6x^3 b.set ( -3, 2 ); //-3x^2 c = a - b; // (7x^4 + x^2) - (6x^3 - 3x^2) a -= b; c.print(); cout << "\n"; a.print(); cout << "\n"; c = a * b; // (7x^4 + x^2) * (6x^3 - 3x^2) c.print(); cout << "\n"; d = c.differentiate().differentiate(); d.print(); cout << "\n"; cout << c.evaluate ( 2 ); //substitue x with 2 cin.get(); } Now, I have the "-" operator overloaded and it works fine: Polynomial Polynomial::operator - ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) c.coef[i] += a.coef[i]; for ( int i = 0; i <= b.deg; i++ ) c.coef[i] -= b.coef[i]; c.deg = c.degree(); return c; } However, I'm having difficulty with my "-=" operator: Polynomial Polynomial::operator -= ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) c.coef[i] += a.coef[i]; for ( int i = 0; i <= b.deg; i++ ) c.coef[i] -= b.coef[i]; c.deg = c.degree(); // overwrite value of 'a' with the newly computed 'c' before returning 'a' for ( int i = 0; i < 100; i++) a.coef[i] = c.coef[i]; a.deg = a.degree(); return a; } I just slightly modified my "-" operator method to overwrite the value in 'a' and return 'a', and just use the 'c' polynomial as a temp. I've put in some debug print statement and I confirm that at the time of computation, both: c = a - b; and a -= b; are computed to the same value. However, when I go to print them, their results are different: Polynomial a, b; a.set ( 7, 4 ); //7x^4 a.set ( 1, 2 ); //x^2 b.set ( 6, 3 ); //6x^3 b.set ( -3, 2 ); //-3x^2 c = a - b; // (7x^4 + x^2) - (6x^3 - 3x^2) a -= b; c.print(); cout << "\n"; a.print(); cout << "\n"; Result: 7x^4 -6x^3 4x^2 7x^4 1x^2 Why is my c = a - b and a -= b giving me different results when I go to print them?

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Disable .htaccess from apache allowoverride none, still reads .htaccess files

- by John Magnolia

I have moved all of our .htaccess config into <Directory> blocks and set AllowOverride None in the default and default-ssl. Although after restarting apache it is still reading the .htaccess files. How can I completely turn off reading these files? Update of all files with "AllowOverride" /etc/apache2/mods-available/userdir.conf <IfModule mod_userdir.c> UserDir public_html UserDir disabled root <Directory /home/*/public_html> AllowOverride FileInfo AuthConfig Limit Indexes Options MultiViews Indexes SymLinksIfOwnerMatch IncludesNoExec <Limit GET POST OPTIONS> Order allow,deny Allow from all </Limit> <LimitExcept GET POST OPTIONS> Order deny,allow Deny from all </LimitExcept> </Directory> </IfModule> /etc/apache2/mods-available/alias.conf <IfModule alias_module> # # Aliases: Add here as many aliases as you need (with no limit). The format is # Alias fakename realname # # Note that if you include a trailing / on fakename then the server will # require it to be present in the URL. So "/icons" isn't aliased in this # example, only "/icons/". If the fakename is slash-terminated, then the # realname must also be slash terminated, and if the fakename omits the # trailing slash, the realname must also omit it. # # We include the /icons/ alias for FancyIndexed directory listings. If # you do not use FancyIndexing, you may comment this out. # Alias /icons/ "/usr/share/apache2/icons/" <Directory "/usr/share/apache2/icons"> Options Indexes MultiViews AllowOverride None Order allow,deny Allow from all </Directory> </IfModule> /etc/apache2/httpd.conf # # Directives to allow use of AWStats as a CGI # Alias /awstatsclasses "/usr/share/doc/awstats/examples/wwwroot/classes/" Alias /awstatscss "/usr/share/doc/awstats/examples/wwwroot/css/" Alias /awstatsicons "/usr/share/doc/awstats/examples/wwwroot/icon/" ScriptAlias /awstats/ "/usr/share/doc/awstats/examples/wwwroot/cgi-bin/" # # This is to permit URL access to scripts/files in AWStats directory. # <Directory "/usr/share/doc/awstats/examples/wwwroot"> Options None AllowOverride None Order allow,deny Allow from all </Directory> Alias /awstats-icon/ /usr/share/awstats/icon/ <Directory /usr/share/awstats/icon> Options None AllowOverride None Order allow,deny Allow from all </Directory> /etc/apache2/sites-available/default-ssl <IfModule mod_ssl.c> <VirtualHost _default_:443> ServerAdmin webmaster@localhost DocumentRoot /var/www <Directory /> Options FollowSymLinks AllowOverride None </Directory> <Directory /var/www/> Options Indexes FollowSymLinks MultiViews AllowOverride None </Directory> ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/ <Directory "/usr/lib/cgi-bin"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all </Directory> ErrorLog ${APACHE_LOG_DIR}/error.log # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. LogLevel warn CustomLog ${APACHE_LOG_DIR}/ssl_access.log combined # SSL Engine Switch: # Enable/Disable SSL for this virtual host. SSLEngine on # A self-signed (snakeoil) certificate can be created by installing # the ssl-cert package. See # /usr/share/doc/apache2.2-common/README.Debian.gz for more info. # If both key and certificate are stored in the same file, only the # SSLCertificateFile directive is needed. SSLCertificateFile /etc/ssl/certs/ssl-cert-snakeoil.pem SSLCertificateKeyFile /etc/ssl/private/ssl-cert-snakeoil.key # Server Certificate Chain: # Point SSLCertificateChainFile at a file containing the # concatenation of PEM encoded CA certificates which form the # certificate chain for the server certificate. Alternatively # the referenced file can be the same as SSLCertificateFile # when the CA certificates are directly appended to the server # certificate for convinience. #SSLCertificateChainFile /etc/apache2/ssl.crt/server-ca.crt # Certificate Authority (CA): # Set the CA certificate verification path where to find CA # certificates for client authentication or alternatively one # huge file containing all of them (file must be PEM encoded) # Note: Inside SSLCACertificatePath you need hash symlinks # to point to the certificate files. Use the provided # Makefile to update the hash symlinks after changes. #SSLCACertificatePath /etc/ssl/certs/ #SSLCACertificateFile /etc/apache2/ssl.crt/ca-bundle.crt # Certificate Revocation Lists (CRL): # Set the CA revocation path where to find CA CRLs for client # authentication or alternatively one huge file containing all # of them (file must be PEM encoded) # Note: Inside SSLCARevocationPath you need hash symlinks # to point to the certificate files. Use the provided # Makefile to update the hash symlinks after changes. #SSLCARevocationPath /etc/apache2/ssl.crl/ #SSLCARevocationFile /etc/apache2/ssl.crl/ca-bundle.crl # Client Authentication (Type): # Client certificate verification type and depth. Types are # none, optional, require and optional_no_ca. Depth is a # number which specifies how deeply to verify the certificate # issuer chain before deciding the certificate is not valid. #SSLVerifyClient require #SSLVerifyDepth 10 # Access Control: # With SSLRequire you can do per-directory access control based # on arbitrary complex boolean expressions containing server # variable checks and other lookup directives. The syntax is a # mixture between C and Perl. See the mod_ssl documentation # for more details. #<Location /> #SSLRequire ( %{SSL_CIPHER} !~ m/^(EXP|NULL)/ \ # and %{SSL_CLIENT_S_DN_O} eq "Snake Oil, Ltd." \ # and %{SSL_CLIENT_S_DN_OU} in {"Staff", "CA", "Dev"} \ # and %{TIME_WDAY} >= 1 and %{TIME_WDAY} <= 5 \ # and %{TIME_HOUR} >= 8 and %{TIME_HOUR} <= 20 ) \ # or %{REMOTE_ADDR} =~ m/^192\.76\.162\.[0-9]+$/ #</Location> # SSL Engine Options: # Set various options for the SSL engine. # o FakeBasicAuth: # Translate the client X.509 into a Basic Authorisation. This means that # the standard Auth/DBMAuth methods can be used for access control. The # user name is the `one line' version of the client's X.509 certificate. # Note that no password is obtained from the user. Every entry in the user # file needs this password: `xxj31ZMTZzkVA'. # o ExportCertData: # This exports two additional environment variables: SSL_CLIENT_CERT and # SSL_SERVER_CERT. These contain the PEM-encoded certificates of the # server (always existing) and the client (only existing when client # authentication is used). This can be used to import the certificates # into CGI scripts. # o StdEnvVars: # This exports the standard SSL/TLS related `SSL_*' environment variables. # Per default this exportation is switched off for performance reasons, # because the extraction step is an expensive operation and is usually # useless for serving static content. So one usually enables the # exportation for CGI and SSI requests only. # o StrictRequire: # This denies access when "SSLRequireSSL" or "SSLRequire" applied even # under a "Satisfy any" situation, i.e. when it applies access is denied # and no other module can change it. # o OptRenegotiate: # This enables optimized SSL connection renegotiation handling when SSL # directives are used in per-directory context. #SSLOptions +FakeBasicAuth +ExportCertData +StrictRequire <FilesMatch "\.(cgi|shtml|phtml|php)$"> SSLOptions +StdEnvVars </FilesMatch> <Directory /usr/lib/cgi-bin> SSLOptions +StdEnvVars </Directory> # SSL Protocol Adjustments: # The safe and default but still SSL/TLS standard compliant shutdown # approach is that mod_ssl sends the close notify alert but doesn't wait for # the close notify alert from client. When you need a different shutdown # approach you can use one of the following variables: # o ssl-unclean-shutdown: # This forces an unclean shutdown when the connection is closed, i.e. no # SSL close notify alert is send or allowed to received. This violates # the SSL/TLS standard but is needed for some brain-dead browsers. Use # this when you receive I/O errors because of the standard approach where # mod_ssl sends the close notify alert. # o ssl-accurate-shutdown: # This forces an accurate shutdown when the connection is closed, i.e. a # SSL close notify alert is send and mod_ssl waits for the close notify # alert of the client. This is 100% SSL/TLS standard compliant, but in # practice often causes hanging connections with brain-dead browsers. Use # this only for browsers where you know that their SSL implementation # works correctly. # Notice: Most problems of broken clients are also related to the HTTP # keep-alive facility, so you usually additionally want to disable # keep-alive for those clients, too. Use variable "nokeepalive" for this. # Similarly, one has to force some clients to use HTTP/1.0 to workaround # their broken HTTP/1.1 implementation. Use variables "downgrade-1.0" and # "force-response-1.0" for this. BrowserMatch "MSIE [2-6]" \ nokeepalive ssl-unclean-shutdown \ downgrade-1.0 force-response-1.0 # MSIE 7 and newer should be able to use keepalive BrowserMatch "MSIE [17-9]" ssl-unclean-shutdown </VirtualHost> </IfModule> /etc/apache2/sites-available/default <VirtualHost *:80> ServerAdmin webmaster@localhost DocumentRoot /var/www <Directory /> Options FollowSymLinks AllowOverride None </Directory> <Directory /var/www/> Options -Indexes FollowSymLinks MultiViews AllowOverride None Order allow,deny allow from all </Directory> ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/ <Directory "/usr/lib/cgi-bin"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all </Directory> Alias /delboy /usr/share/phpmyadmin <Directory /usr/share/phpmyadmin> # Restrict phpmyadmin access Order Deny,Allow Allow from all </Directory> ErrorLog ${APACHE_LOG_DIR}/error.log # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. LogLevel warn CustomLog ${APACHE_LOG_DIR}/access.log combined Alias /doc/ "/usr/share/doc/" <Directory "/usr/share/doc/"> Options Indexes MultiViews FollowSymLinks AllowOverride None Order deny,allow Deny from all Allow from 127.0.0.0/255.0.0.0 ::1/128 </Directory> </VirtualHost> /etc/apache2/conf.d/security # # Disable access to the entire file system except for the directories that # are explicitly allowed later. # # This currently breaks the configurations that come with some web application # Debian packages. # #<Directory /> # AllowOverride None # Order Deny,Allow # Deny from all #</Directory> # Changing the following options will not really affect the security of the # server, but might make attacks slightly more difficult in some cases. # # ServerTokens # This directive configures what you return as the Server HTTP response # Header. The default is 'Full' which sends information about the OS-Type # and compiled in modules. # Set to one of: Full | OS | Minimal | Minor | Major | Prod # where Full conveys the most information, and Prod the least. # #ServerTokens Minimal ServerTokens OS #ServerTokens Full # # Optionally add a line containing the server version and virtual host # name to server-generated pages (internal error documents, FTP directory # listings, mod_status and mod_info output etc., but not CGI generated # documents or custom error documents). # Set to "EMail" to also include a mailto: link to the ServerAdmin. # Set to one of: On | Off | EMail # #ServerSignature Off ServerSignature On # # Allow TRACE method # # Set to "extended" to also reflect the request body (only for testing and # diagnostic purposes). # # Set to one of: On | Off | extended # TraceEnable Off #TraceEnable On /etc/apache2/apache2.conf # # Based upon the NCSA server configuration files originally by Rob McCool. # # This is the main Apache server configuration file. It contains the # configuration directives that give the server its instructions. # See http://httpd.apache.org/docs/2.2/ for detailed information about # the directives. # # Do NOT simply read the instructions in here without understanding # what they do. They're here only as hints or reminders. If you are unsure # consult the online docs. You have been warned. # # The configuration directives are grouped into three basic sections: # 1. Directives that control the operation of the Apache server process as a # whole (the 'global environment'). # 2. Directives that define the parameters of the 'main' or 'default' server, # which responds to requests that aren't handled by a virtual host. # These directives also provide default values for the settings # of all virtual hosts. # 3. Settings for virtual hosts, which allow Web requests to be sent to # different IP addresses or hostnames and have them handled by the # same Apache server process. # # Configuration and logfile names: If the filenames you specify for many # of the server's control files begin with "/" (or "drive:/" for Win32), the # server will use that explicit path. If the filenames do *not* begin # with "/", the value of ServerRoot is prepended -- so "foo.log" # with ServerRoot set to "/etc/apache2" will be interpreted by the # server as "/etc/apache2/foo.log". # ### Section 1: Global Environment # # The directives in this section affect the overall operation of Apache, # such as the number of concurrent requests it can handle or where it # can find its configuration files. # # # ServerRoot: The top of the directory tree under which the server's # configuration, error, and log files are kept. # # NOTE! If you intend to place this on an NFS (or otherwise network) # mounted filesystem then please read the LockFile documentation (available # at <URL:http://httpd.apache.org/docs/2.2/mod/mpm_common.html#lockfile>); # you will save yourself a lot of trouble. # # Do NOT add a slash at the end of the directory path. # #ServerRoot "/etc/apache2" # # The accept serialization lock file MUST BE STORED ON A LOCAL DISK. # LockFile ${APACHE_LOCK_DIR}/accept.lock # # PidFile: The file in which the server should record its process # identification number when it starts. # This needs to be set in /etc/apache2/envvars # PidFile ${APACHE_PID_FILE} # # Timeout: The number of seconds before receives and sends time out. # Timeout 300 # # KeepAlive: Whether or not to allow persistent connections (more than # one request per connection). Set to "Off" to deactivate. # KeepAlive On # # MaxKeepAliveRequests: The maximum number of requests to allow # during a persistent connection. Set to 0 to allow an unlimited amount. # We recommend you leave this number high, for maximum performance. # MaxKeepAliveRequests 100 # # KeepAliveTimeout: Number of seconds to wait for the next request from the # same client on the same connection. # KeepAliveTimeout 4 ## ## Server-Pool Size Regulation (MPM specific) ## # prefork MPM # StartServers: number of server processes to start # MinSpareServers: minimum number of server processes which are kept spare # MaxSpareServers: maximum number of server processes which are kept spare # MaxClients: maximum number of server processes allowed to start # MaxRequestsPerChild: maximum number of requests a server process serves <IfModule mpm_prefork_module> StartServers 5 MinSpareServers 5 MaxSpareServers 10 MaxClients 150 MaxRequestsPerChild 500 </IfModule> # worker MPM # StartServers: initial number of server processes to start # MaxClients: maximum number of simultaneous client connections # MinSpareThreads: minimum number of worker threads which are kept spare # MaxSpareThreads: maximum number of worker threads which are kept spare # ThreadLimit: ThreadsPerChild can be changed to this maximum value during a # graceful restart. ThreadLimit can only be changed by stopping # and starting Apache. # ThreadsPerChild: constant number of worker threads in each server process # MaxRequestsPerChild: maximum number of requests a server process serves <IfModule mpm_worker_module> StartServers 2 MinSpareThreads 25 MaxSpareThreads 75 ThreadLimit 64 ThreadsPerChild 25 MaxClients 150 MaxRequestsPerChild 0 </IfModule> # event MPM # StartServers: initial number of server processes to start # MaxClients: maximum number of simultaneous client connections # MinSpareThreads: minimum number of worker threads which are kept spare # MaxSpareThreads: maximum number of worker threads which are kept spare # ThreadsPerChild: constant number of worker threads in each server process # MaxRequestsPerChild: maximum number of requests a server process serves <IfModule mpm_event_module> StartServers 2 MaxClients 150 MinSpareThreads 25 MaxSpareThreads 75 ThreadLimit 64 ThreadsPerChild 25 MaxRequestsPerChild 0 </IfModule> # These need to be set in /etc/apache2/envvars User ${APACHE_RUN_USER} Group ${APACHE_RUN_GROUP} # # AccessFileName: The name of the file to look for in each directory # for additional configuration directives. See also the AllowOverride # directive. # AccessFileName .htaccess # # The following lines prevent .htaccess and .htpasswd files from being # viewed by Web clients. # <Files ~ "^\.ht"> Order allow,deny Deny from all Satisfy all </Files> # # DefaultType is the default MIME type the server will use for a document # if it cannot otherwise determine one, such as from filename extensions. # If your server contains mostly text or HTML documents, "text/plain" is # a good value. If most of your content is binary, such as applications # or images, you may want to use "application/octet-stream" instead to # keep browsers from trying to display binary files as though they are # text. # DefaultType text/plain # # HostnameLookups: Log the names of clients or just their IP addresses # e.g., www.apache.org (on) or 204.62.129.132 (off). # The default is off because it'd be overall better for the net if people # had to knowingly turn this feature on, since enabling it means that # each client request will result in AT LEAST one lookup request to the # nameserver. # HostnameLookups Off # ErrorLog: The location of the error log file. # If you do not specify an ErrorLog directive within a <VirtualHost> # container, error messages relating to that virtual host will be # logged here. If you *do* define an error logfile for a <VirtualHost> # container, that host's errors will be logged there and not here. # ErrorLog ${APACHE_LOG_DIR}/error.log # # LogLevel: Control the number of messages logged to the error_log. # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. # LogLevel warn # Include module configuration: Include mods-enabled/*.load Include mods-enabled/*.conf # Include all the user configurations: Include httpd.conf # Include ports listing Include ports.conf # # The following directives define some format nicknames for use with # a CustomLog directive (see below). # If you are behind a reverse proxy, you might want to change %h into %{X-Forwarded-For}i # LogFormat "%v:%p %h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" vhost_combined LogFormat "%h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" combined LogFormat "%h %l %u %t \"%r\" %>s %O" common LogFormat "%{Referer}i -> %U" referer LogFormat "%{User-agent}i" agent # Include of directories ignores editors' and dpkg's backup files, # see README.Debian for details. # Include generic snippets of statements Include conf.d/ # Include the virtual host configurations: Include sites-enabled/

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trouble running smooth animation in thread only when using key listener

- by heysuse renard

first time using a forum for coding help so sorry if i post this all wrong. i have more than a few classes i don't think screenManger or core holds the problem but i included them just incase. i got most of this code working through a set of tutorials. but a certain point started trying to do more on my own. i want to play the animation only when i'm moving my sprite. in my KeyTest class i am using threads to run the animation it used to work (poorly) but now not at all pluss it really gunks up my computer. i think it's because of the thread. im new to threads so i'm not to sure if i should even be using one in this situation or if its dangerous for my computer. the animation worked smoothly when i had the sprite bouce around the screen forever. the animation loop played with out stopping. i think the main problem is between the animationThread, Sprite, and keyTest classes, but itcould be more indepth. if someone could point me in the right direction for making the animation run smoothly when i push down a key and stop runing when i let off it would be greatly apriciated. i already looked at this Java a moving animation (sprite) obviously we were doing the same tutorial. but i feel my problem is slightly different. p.s. sorry for the typos. import java.awt.*; import java.awt.event.KeyEvent; import java.awt.event.KeyListener; import java.awt.image.BufferStrategy; import java.awt.image.BufferedImage; import java.util.ArrayList; import javax.swing.ImageIcon; import javax.swing.JFrame; public class KeyTest extends Core implements KeyListener { public static void main(String[] args) { new KeyTest().run(); } Sprite player1; Image hobo; Image background; animation hoboRun; animationThread t1; //init also calls init form superclass public void init() { super.init(); loadImages(); Window w = s.getFullScreenWindow(); w.setFocusTraversalKeysEnabled(false); w.addKeyListener(this); } //load method will go here. //load all pics need for animation and sprite public void loadImages() { background = new ImageIcon("\\\\STUART-PC\\Users\\Stuart\\workspace\\Gaming\\yellow square.jpg").getImage(); Image face1 = new ImageIcon("\\\\STUART-PC\\Users\\Stuart\\workspace\\Gaming\\circle.png").getImage(); Image face2 = new ImageIcon("\\\\STUART-PC\\Users\\Stuart\\workspace\\Gaming\\one eye.png").getImage(); hoboRun = new animation(); hoboRun.addScene(face1, 250); hoboRun.addScene(face2, 250); player1 = new Sprite(hoboRun); this.t1 = new animationThread(); this.t1.setAnimation(player1); } //key pressed public void keyPressed(KeyEvent e) { int keyCode = e.getKeyCode(); if (keyCode == KeyEvent.VK_ESCAPE) { stop(); } if (keyCode == KeyEvent.VK_RIGHT) { player1.setVelocityX(0.3f); try { this.t1.setRunning(true); Thread th1 = new Thread(this.t1); th1.start(); } catch (Exception ex) { System.out.println("noooo"); } } if (keyCode == KeyEvent.VK_LEFT) { player1.setVelocityX(-0.3f); try { this.t1.setRunning(true); Thread th1 = new Thread(this.t1); th1.start(); } catch (Exception ex) { System.out.println("noooo"); } } if (keyCode == KeyEvent.VK_DOWN) { player1.setVelocityY(0.3f); try { this.t1.setRunning(true); Thread th1 = new Thread(this.t1); th1.start(); } catch (Exception ex) { System.out.println("noooo"); } } if (keyCode == KeyEvent.VK_UP) { player1.setVelocityY(-0.3f); try { this.t1.setRunning(true); Thread th1 = new Thread(this.t1);; th1.start(); } catch (Exception ex) { System.out.println("noooo"); } } else { e.consume(); } } //keyReleased @SuppressWarnings("static-access") public void keyReleased(KeyEvent e) { int keyCode = e.getKeyCode(); if (keyCode == KeyEvent.VK_RIGHT || keyCode == KeyEvent.VK_LEFT) { player1.setVelocityX(0); try { this.t1.setRunning(false); } catch (Exception ex) { } } if (keyCode == KeyEvent.VK_UP || keyCode == KeyEvent.VK_DOWN) { player1.setVelocityY(0); try { this.t1.setRunning(false); } catch (Exception ex) { } } else { e.consume(); } } //last method from interface public void keyTyped(KeyEvent e) { e.consume(); } //draw public void draw(Graphics2D g) { Window w = s.getFullScreenWindow(); g.setColor(w.getBackground()); g.fillRect(0, 0, s.getWidth(), s.getHieght()); g.setColor(w.getForeground()); g.drawImage(player1.getImage(), Math.round(player1.getX()), Math.round(player1.getY()), null); } public void update(long timePassed) { player1.update(timePassed); } } abstract class Core { private static DisplayMode modes[] = { new DisplayMode(1600, 900, 64, 0), new DisplayMode(800, 600, 32, 0), new DisplayMode(800, 600, 24, 0), new DisplayMode(800, 600, 16, 0), new DisplayMode(800, 480, 32, 0), new DisplayMode(800, 480, 24, 0), new DisplayMode(800, 480, 16, 0),}; private boolean running; protected ScreenManager s; //stop method public void stop() { running = false; } public void run() { try { init(); gameLoop(); } finally { s.restoreScreen(); } } //set to full screen //set current background here public void init() { s = new ScreenManager(); DisplayMode dm = s.findFirstCompatibleMode(modes); s.setFullScreen(dm); Window w = s.getFullScreenWindow(); w.setFont(new Font("Arial", Font.PLAIN, 20)); w.setBackground(Color.GREEN); w.setForeground(Color.WHITE); running = true; } //main gameLoop public void gameLoop() { long startTime = System.currentTimeMillis(); long cumTime = startTime; while (running) { long timePassed = System.currentTimeMillis() - cumTime; cumTime += timePassed; update(timePassed); Graphics2D g = s.getGraphics(); draw(g); g.dispose(); s.update(); try { Thread.sleep(20); } catch (Exception ex) { } } } //update animation public void update(long timePassed) { } //draws to screen abstract void draw(Graphics2D g); } class animationThread implements Runnable { String name; boolean playing; Sprite a; //constructor takes input from keyboard public animationThread() { } //The run method for animation public void run() { long startTime = System.currentTimeMillis(); long cumTime = startTime; boolean test = getRunning(); while (test) { long timePassed = System.currentTimeMillis() - cumTime; cumTime += timePassed; test = getRunning(); } } public String getName() { return name; } public void setAnimation(Sprite a) { this.a = a; } public void setName(String name) { this.name = name; } public void setRunning(boolean running) { this.playing = running; } public boolean getRunning() { return playing; } } class animation { private ArrayList scenes; private int sceneIndex; private long movieTime; private long totalTime; //constructor public animation() { scenes = new ArrayList(); totalTime = 0; start(); } //add scene to ArrayLisy and set time for each scene public synchronized void addScene(Image i, long t) { totalTime += t; scenes.add(new OneScene(i, totalTime)); } public synchronized void start() { movieTime = 0; sceneIndex = 0; } //change scenes public synchronized void update(long timePassed) { if (scenes.size() > 1) { movieTime += timePassed; if (movieTime >= totalTime) { movieTime = 0; sceneIndex = 0; } while (movieTime > getScene(sceneIndex).endTime) { sceneIndex++; } } } //get animations current scene(aka image) public synchronized Image getImage() { if (scenes.size() == 0) { return null; } else { return getScene(sceneIndex).pic; } } //get scene private OneScene getScene(int x) { return (OneScene) scenes.get(x); } //Private Inner CLASS////////////// private class OneScene { Image pic; long endTime; public OneScene(Image pic, long endTime) { this.pic = pic; this.endTime = endTime; } } } class Sprite { private animation a; private float x; private float y; private float vx; private float vy; //Constructor public Sprite(animation a) { this.a = a; } //change position public void update(long timePassed) { x += vx * timePassed; y += vy * timePassed; } public void startAnimation(long timePassed) { a.update(timePassed); } //get x position public float getX() { return x; } //get y position public float getY() { return y; } //set x public void setX(float x) { this.x = x; } //set y public void setY(float y) { this.y = y; } //get sprite width public int getWidth() { return a.getImage().getWidth(null); } //get sprite height public int getHeight() { return a.getImage().getHeight(null); } //get horizontal velocity public float getVelocityX() { return vx; } //get vertical velocity public float getVelocityY() { return vx; } //set horizontal velocity public void setVelocityX(float vx) { this.vx = vx; } //set vertical velocity public void setVelocityY(float vy) { this.vy = vy; } //get sprite / image public Image getImage() { return a.getImage(); } } class ScreenManager { private GraphicsDevice vc; public ScreenManager() { GraphicsEnvironment e = GraphicsEnvironment.getLocalGraphicsEnvironment(); vc = e.getDefaultScreenDevice(); } //get all compatible DM public DisplayMode[] getCompatibleDisplayModes() { return vc.getDisplayModes(); } //compares DM passed into vc DM and see if they match public DisplayMode findFirstCompatibleMode(DisplayMode modes[]) { DisplayMode goodModes[] = vc.getDisplayModes(); for (int x = 0; x < modes.length; x++) { for (int y = 0; y < goodModes.length; y++) { if (displayModesMatch(modes[x], goodModes[y])) { return modes[x]; } } } return null; } //get current DM public DisplayMode getCurrentDisplayMode() { return vc.getDisplayMode(); } //checks if two modes match each other public boolean displayModesMatch(DisplayMode m1, DisplayMode m2) { if (m1.getWidth() != m2.getWidth() || m1.getHeight() != m2.getHeight()) { return false; } if (m1.getBitDepth() != DisplayMode.BIT_DEPTH_MULTI && m2.getBitDepth() != DisplayMode.BIT_DEPTH_MULTI && m1.getBitDepth() != m2.getBitDepth()) { return false; } if (m1.getRefreshRate() != DisplayMode.REFRESH_RATE_UNKNOWN && m2.getRefreshRate() != DisplayMode.REFRESH_RATE_UNKNOWN && m1.getRefreshRate() != m2.getRefreshRate()) { return false; } return true; } //make frame full screen public void setFullScreen(DisplayMode dm) { JFrame f = new JFrame(); f.setUndecorated(true); f.setIgnoreRepaint(true); f.setResizable(false); vc.setFullScreenWindow(f); if (dm != null && vc.isDisplayChangeSupported()) { try { vc.setDisplayMode(dm); } catch (Exception ex) { } } f.createBufferStrategy(2); } //sets graphics object = this return public Graphics2D getGraphics() { Window w = vc.getFullScreenWindow(); if (w != null) { BufferStrategy s = w.getBufferStrategy(); return (Graphics2D) s.getDrawGraphics(); } else { return null; } } //updates display public void update() { Window w = vc.getFullScreenWindow(); if (w != null) { BufferStrategy s = w.getBufferStrategy(); if (!s.contentsLost()) { s.show(); } } } //returns full screen window public Window getFullScreenWindow() { return vc.getFullScreenWindow(); } //get width of window public int getWidth() { Window w = vc.getFullScreenWindow(); if (w != null) { return w.getWidth(); } else { return 0; } } //get height of window public int getHieght() { Window w = vc.getFullScreenWindow(); if (w != null) { return w.getHeight(); } else { return 0; } } //get out of full screen public void restoreScreen() { Window w = vc.getFullScreenWindow(); if (w != null) { w.dispose(); } vc.setFullScreenWindow(null); } //create image compatible with monitor public BufferedImage createCopatibleImage(int w, int h, int t) { Window win = vc.getFullScreenWindow(); if (win != null) { GraphicsConfiguration gc = win.getGraphicsConfiguration(); return gc.createCompatibleImage(w, h, t); } return null; } }

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Scripting with the Sun ZFS Storage 7000 Appliance

- by Geoff Ongley

The Sun ZFS Storage 7000 appliance has a user friendly and easy to understand graphical web based interface we call the "BUI" or "Browser User Interface".This interface is very useful for many tasks, but in some cases a script (or workflow) may be more appropriate, such as:Repetitive tasksTasks which work on (or obtain information about) a large number of shares or usersTasks which are triggered by an alert threshold (workflows)Tasks where you want a only very basic input, but a consistent output (workflows)The appliance scripting language is based on ECMAscript 3 (close to javascript). I'm not going to cover ECMAscript 3 in great depth (I'm far from an expert here), but I would like to show you some neat things you can do with the appliance, to get you started based on what I have found from my own playing around.I'm making the assumption you have some sort of programming background, and understand variables, arrays, functions to some extent - but of course if something is not clear, please let me know so I can fix it up or clarify it.Variable Declarations and ArraysVariablesECMAScript is a dynamically and weakly typed language. If you don't know what that means, google is your friend - but at a high level it means we can just declare variables with no specific type and on the fly.For example, I can declare a variable and use it straight away in the middle of my code, for example:projects=list();Which makes projects an array of values that are returned from the list(); function (which is usable in most contexts). With this kind of variable, I can do things like:projects.length (this property on array tells you how many objects are in it, good for for loops etc). Alternatively, I could say:projects=3;and now projects is just a simple number.Should we declare variables like this so loosely? In my opinion, the answer is no - I feel it is a better practice to declare variables you are going to use, before you use them - and given them an initial value. You can do so as follows:var myVariable=0;To demonstrate the ability to just randomly assign and change the type of variables, you can create a simple script at the cli as follows (bold for input):fishy10:> script("." to run)> run("cd /");("." to run)> run ("shares");("." to run)> var projects;("." to run)> projects=list();("." to run)> printf("Number of projects is: %d\n",projects.length);("." to run)> projects=152;("." to run)> printf("Value of the projects variable as an integer is now: %d\n",projects);("." to run)> .Number of projects is: 7Value of the projects variable as an integer is now: 152You can also confirm this behaviour by checking the typeof variable we are dealing with:fishy10:> script("." to run)> run("cd /");("." to run)> run ("shares");("." to run)> var projects;("." to run)> projects=list();("." to run)> printf("var projects is of type %s\n",typeof(projects));("." to run)> projects=152;("." to run)> printf("var projects is of type %s\n",typeof(projects));("." to run)> .var projects is of type objectvar projects is of type numberArraysSo you likely noticed that we have already touched on arrays, as the list(); (in the shares context) stored an array into the 'projects' variable.But what if you want to declare your own array? Easy! This is very similar to Java and other languages, we just instantiate a brand new "Array" object using the keyword new:var myArray = new Array();will create an array called "myArray".A quick example:fishy10:> script("." to run)> testArray = new Array();("." to run)> testArray[0]="This";("." to run)> testArray[1]="is";("." to run)> testArray[2]="just";("." to run)> testArray[3]="a";("." to run)> testArray[4]="test";("." to run)> for (i=0; i < testArray.length; i++)("." to run)> {("." to run)> printf("Array element %d is %s\n",i,testArray[i]);("." to run)> }("." to run)> .Array element 0 is ThisArray element 1 is isArray element 2 is justArray element 3 is aArray element 4 is testWorking With LoopsFor LoopFor loops are very similar to those you will see in C, java and several other languages. One of the key differences here is, as you were made aware earlier, we can be a bit more sloppy with our variable declarations.The general way you would likely use a for loop is as follows:for (variable; test-case; modifier for variable){}For example, you may wish to declare a variable i as 0; and a MAX_ITERATIONS variable to determine how many times this loop should repeat:var i=0;var MAX_ITERATIONS=10;And then, use this variable to be tested against some case existing (has i reached MAX_ITERATIONS? - if not, increment i using i++);for (i=0; i < MAX_ITERATIONS; i++){ // some work to do}So lets run something like this on the appliance:fishy10:> script("." to run)> var i=0;("." to run)> var MAX_ITERATIONS=10;("." to run)> for (i=0; i < MAX_ITERATIONS; i++)("." to run)> {("." to run)> printf("The number is %d\n",i);("." to run)> }("." to run)> .The number is 0The number is 1The number is 2The number is 3The number is 4The number is 5The number is 6The number is 7The number is 8The number is 9While LoopWhile loops again are very similar to other languages, we loop "while" a condition is met. For example:fishy10:> script("." to run)> var isTen=false;("." to run)> var counter=0;("." to run)> while(isTen==false)("." to run)> {("." to run)> if (counter==10) ("." to run)> { ("." to run)> isTen=true; ("." to run)> } ("." to run)> printf("Counter is %d\n",counter);("." to run)> counter++; ("." to run)> }("." to run)> printf("Loop has ended and Counter is %d\n",counter);("." to run)> .Counter is 0Counter is 1Counter is 2Counter is 3Counter is 4Counter is 5Counter is 6Counter is 7Counter is 8Counter is 9Counter is 10Loop has ended and Counter is 11So what do we notice here? Something has actually gone wrong - counter will technically be 11 once the loop completes... Why is this?Well, if we have a loop like this, where the 'while' condition that will end the loop may be set based on some other condition(s) existing (such as the counter has reached 10) - we must ensure that we terminate this iteration of the loop when the condition is met - otherwise the rest of the code will be followed which may not be desirable. In other words, like in other languages, we will only ever check the loop condition once we are ready to perform the next iteration, so any other code after we set "isTen" to be true, will still be executed as we can see it was above.We can avoid this by adding a break into our loop once we know we have set the condition - this will stop the rest of the logic being processed in this iteration (and as such, counter will not be incremented). So lets try that again:fishy10:> script("." to run)> var isTen=false;("." to run)> var counter=0;("." to run)> while(isTen==false)("." to run)> {("." to run)> if (counter==10) ("." to run)> { ("." to run)> isTen=true; ("." to run)> break;("." to run)> } ("." to run)> printf("Counter is %d\n",counter);("." to run)> counter++; ("." to run)> }("." to run)> printf("Loop has ended and Counter is %d\n", counter);("." to run)> .Counter is 0Counter is 1Counter is 2Counter is 3Counter is 4Counter is 5Counter is 6Counter is 7Counter is 8Counter is 9Loop has ended and Counter is 10Much better!Methods to Obtain and Manipulate DataGet MethodThe get method allows you to get simple properties from an object, for example a quota from a user. The syntax is fairly simple:var myVariable=get('property');An example of where you may wish to use this, is when you are getting a bunch of information about a user (such as quota information when in a shares context):var users=list();for(k=0; k < users.length; k++){ user=users[k]; run('select ' + user); var username=get('name'); var usage=get('usage'); var quota=get('quota');...Which you can then use to your advantage - to print or manipulate infomation (you could change a user's information with a set method, based on the information returned from the get method). The set method is explained next.Set MethodThe set method can be used in a simple manner, similar to get. The syntax for set is:set('property','value'); // where value is a string, if it was a number, you don't need quotesFor example, we could set the quota on a share as follows (first observing the initial value):fishy10:shares default/test-geoff> script("." to run)> var currentQuota=get('quota');("." to run)> printf("Current Quota is: %s\n",currentQuota);("." to run)> set('quota','30G');("." to run)> run('commit');("." to run)> currentQuota=get('quota');("." to run)> printf("Current Quota is: %s\n",currentQuota);("." to run)> .Current Quota is: 0Current Quota is: 32212254720This shows us using both the get and set methods as can be used in scripts, of course when only setting an individual share, the above is overkill - it would be much easier to set it manually at the cli using 'set quota=3G' and then 'commit'.List MethodThe list method can be very powerful, especially in more complex scripts which iterate over large amounts of data and manipulate it if so desired. The general way you will use list is as follows:var myVar=list();Which will make "myVar" an array, containing all the objects in the relevant context (this could be a list of users, shares, projects, etc). You can then gather or manipulate data very easily.We could list all the shares and mountpoints in a given project for example:fishy10:shares another-project> script("." to run)> var shares=list();("." to run)> for (i=0; i < shares.length; i++)("." to run)> {("." to run)> run('select ' + shares[i]);("." to run)> var mountpoint=get('mountpoint');("." to run)> printf("Share %s discovered, has mountpoint %s\n",shares[i],mountpoint);("." to run)> run('done');("." to run)> }("." to run)> .Share and-another discovered, has mountpoint /export/another-project/and-anotherShare another-share discovered, has mountpoint /export/another-project/another-shareShare bob discovered, has mountpoint /export/another-projectShare more-shares-for-all discovered, has mountpoint /export/another-project/more-shares-for-allShare yep discovered, has mountpoint /export/another-project/yepWriting More Complex and Re-Usable CodeFunctionsThe best way to be able to write more complex code is to use functions to split up repeatable or reusable sections of your code. This also makes your more complex code easier to read and understand for other programmers.We write functions as follows:function functionName(variable1,variable2,...,variableN){}For example, we could have a function that takes a project name as input, and lists shares for that project (assuming we're already in the 'project' context - context is important!):function getShares(proj){ run('select ' + proj); shares=list(); printf("Project: %s\n", proj); for(j=0; j < shares.length; j++) { printf("Discovered share: %s\n",shares[i]); } run('done'); // exit selected project}Commenting your CodeLike any other language, a large part of making it readable and understandable is to comment it. You can use the same comment style as in C and Java amongst other languages.In other words, sngle line comments use://at the beginning of the comment.Multi line comments use:/*at the beginning, and:*/ at the end.For example, here we will use both:fishy10:> script("." to run)> // This is a test comment("." to run)> printf("doing some work...\n");("." to run)> /* This is a multi-line("." to run)> comment which I will span across("." to run)> three lines in total */("." to run)> printf("doing some more work...\n");("." to run)> .doing some work...doing some more work...Your comments do not have to be on their own, they can begin (particularly with single line comments this is handy) at the end of a statement, for examplevar projects=list(); // The variable projects is an array containing all projects on the system.Try and Catch StatementsYou may be used to using try and catch statements in other languages, and they can (and should) be utilised in your code to catch expected or unexpected error conditions, that you do NOT wish to stop your code from executing (if you do not catch these errors, your script will exit!):try{ // do some work}catch(err) // Catch any error that could occur{ // do something here under the error condition}For example, you may wish to only execute some code if a context can be reached. If you can't perform certain actions under certain circumstances, that may be perfectly acceptable.For example if you want to test a condition that only makes sense when looking at a SMB/NFS share, but does not make sense when you hit an iscsi or FC LUN, you don't want to stop all processing of other shares you may not have covered yet.For example we may wish to obtain quota information on all shares for all users on a share (but this makes no sense for a LUN):function getShareQuota(shar) // Get quota for each user of this share{ run('select ' + shar); printf(" SHARE: %s\n", shar); try { run('users'); printf(" %20s %11s %11s %3s\n","Username","Usage(G)","Quota(G)","Quota(%)"); printf(" %20s %11s %11s %4s\n","--------","--------","--------","----"); users=list(); for(k=0; k < users.length; k++) { user=users[k]; getUserQuota(user); } run('done'); // exit user context } catch(err) { printf(" SKIPPING %s - This is NOT a NFS or CIFs share, not looking for users\n", shar); } run('done'); // done with this share}Running Scripts Remotely over SSHAs you have likely noticed, writing and running scripts for all but the simplest jobs directly on the appliance is not going to be a lot of fun.There's a couple of choices on what you can do here:Create scripts on a remote system and run them over sshCreate scripts, wrapping them in workflow code, so they are stored on the appliance and can be triggered under certain circumstances (like a threshold being reached)We'll cover the first one here, and then cover workflows later on (as these are for the most part just scripts with some wrapper information around them).Creating a SSH Public/Private SSH Key PairLog on to your handy Solaris box (You wouldn't be using any other OS, right? :P) and use ssh-keygen to create a pair of ssh keys. I'm storing this separate to my normal key:[geoff@lightning ~] ssh-keygen -t rsa -b 1024Generating public/private rsa key pair.Enter file in which to save the key (/export/home/geoff/.ssh/id_rsa): /export/home/geoff/.ssh/nas_key_rsaEnter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /export/home/geoff/.ssh/nas_key_rsa.Your public key has been saved in /export/home/geoff/.ssh/nas_key_rsa.pub.The key fingerprint is:7f:3d:53:f0:2a:5e:8b:2d:94:2a:55:77:66:5c:9b:14 geoff@lightningInstalling the Public Key on the ApplianceOn your Solaris host, observe the public key:[geoff@lightning ~] cat .ssh/nas_key_rsa.pub ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAvYfK3RIaAYmMHBOvyhKM41NaSmcgUMC3igPN5gUKJQvSnYmjuWG6CBr1CkF5UcDji7v19jG3qAD5lAMFn+L0CxgRr8TNaAU+hA4/tpAGkjm+dKYSyJgEdMIURweyyfUFXoerweR8AWW5xlovGKEWZTAfvJX9Zqvh8oMQ5UJLUUc= geoff@lightningNow, copy and paste everything after "ssh-rsa" and before "user@hostname" - in this case, geoff@lightning. That is, this bit:AAAAB3NzaC1yc2EAAAABIwAAAIEAvYfK3RIaAYmMHBOvyhKM41NaSmcgUMC3igPN5gUKJQvSnYmjuWG6CBr1CkF5UcDji7v19jG3qAD5lAMFn+L0CxgRr8TNaAU+hA4/tpAGkjm+dKYSyJgEdMIURweyyfUFXoerweR8AWW5xlovGKEWZTAfvJX9Zqvh8oMQ5UJLUUc=Logon to your appliance and get into the preferences -> keys area for this user (root):[geoff@lightning ~] ssh [email protected]: Last login: Mon Dec 6 17:13:28 2010 from 192.168.0.2fishy10:> configuration usersfishy10:configuration users> select rootfishy10:configuration users root> preferences fishy10:configuration users root preferences> keysOR do it all in one hit:fishy10:> configuration users select root preferences keysNow, we create a new public key that will be accepted for this user and set the type to RSA:fishy10:configuration users root preferences keys> createfishy10:configuration users root preferences key (uncommitted)> set type=RSASet the key itself using the string copied previously (between ssh-rsa and user@host), and set the key ensuring you put double quotes around it (eg. set key="<key>"):fishy10:configuration users root preferences key (uncommitted)> set key="AAAAB3NzaC1yc2EAAAABIwAAAIEAvYfK3RIaAYmMHBOvyhKM41NaSmcgUMC3igPN5gUKJQvSnYmjuWG6CBr1CkF5UcDji7v19jG3qAD5lAMFn+L0CxgRr8TNaAU+hA4/tpAGkjm+dKYSyJgEdMIURweyyfUFXoerweR8AWW5xlovGKEWZTAfvJX9Zqvh8oMQ5UJLUUc="Now set the comment for this key (do not use spaces):fishy10:configuration users root preferences key (uncommitted)> set comment="LightningRSAKey" Commit the new key:fishy10:configuration users root preferences key (uncommitted)> commitVerify the key is there:fishy10:configuration users root preferences keys> lsKeys:NAME MODIFIED TYPE COMMENT key-000 2010-10-25 20:56:42 RSA cycloneRSAKey key-001 2010-12-6 17:44:53 RSA LightningRSAKey As you can see, we now have my new key, and a previous key I have created on this appliance.Running your Script over SSH from a Remote SystemHere I have created a basic test script, and saved it as test.ecma3:[geoff@lightning ~] cat test.ecma3 script// This is a test script, By Geoff Ongley 2010.printf("Testing script remotely over ssh\n");.Now, we can run this script remotely with our keyless login:[geoff@lightning ~] ssh -i .ssh/nas_key_rsa root@fishy10 < test.ecma3Pseudo-terminal will not be allocated because stdin is not a terminal.Testing script remotely over sshPutting it Together - An Example Completed Quota Gathering ScriptSo now we have a lot of the basics to creating a script, let us do something useful, like, find out how much every user is using, on every share on the system (you will recognise some of the code from my previous examples): script/************************************** Quick and Dirty Quota Check script ** Written By Geoff Ongley ** 25 October 2010 **************************************/function getUserQuota(usr){ run('select ' + usr); var username=get('name'); var usage=get('usage'); var quota=get('quota'); var usage_g=usage / 1073741824; // convert bytes to gigabytes var quota_g=quota / 1073741824; // as above var quota_percent=0 if (quota > 0) { quota_percent=(usage / quota)*(100/1); } printf(" %20s %8.2f %8.2f %d%%\n",username,usage_g,quota_g,quota_percent); run('done'); // done with this selected user}function getShareQuota(shar){ //printf("DEBUG: selecting share %s\n", shar); run('select ' + shar); printf(" SHARE: %s\n", shar); try { run('users'); printf(" %20s %11s %11s %3s\n","Username","Usage(G)","Quota(G)","Quota(%)"); printf(" %20s %11s %11s %4s\n","--------","--------","--------","--------"); users=list(); for(k=0; k < users.length; k++) { user=users[k]; getUserQuota(user); } run('done'); // exit user context } catch(err) { printf(" SKIPPING %s - This is NOT a NFS or CIFs share, not looking for users\n", shar); } run('done'); // done with this share}function getShares(proj){ //printf("DEBUG: selecting project %s\n",proj); run('select ' + proj); shares=list(); printf("Project: %s\n", proj); for(j=0; j < shares.length; j++) { share=shares[j]; getShareQuota(share); } run('done'); // exit selected project}function getProjects(){ run('cd /'); run('shares'); projects=list(); for (i=0; i < projects.length; i++) { var project=projects[i]; getShares(project); } run('done'); // exit context for all projects}getProjects();.Which can be run as follows, and will print information like this:[geoff@lightning ~/FISHWORKS_SCRIPTS] ssh -i ~/.ssh/nas_key_rsa root@fishy10 < get_quota_utilisation.ecma3Pseudo-terminal will not be allocated because stdin is not a terminal.Project: another-project SHARE: and-another Username Usage(G) Quota(G) Quota(%) -------- -------- -------- -------- nobody 0.00 0.00 0% geoffro 0.05 0.00 0% Billy 0.10 0.00 0% root 0.00 0.00 0% testing-user 0.05 0.00 0% SHARE: another-share Username Usage(G) Quota(G) Quota(%) -------- -------- -------- -------- root 0.00 0.00 0% nobody 0.00 0.00 0% geoffro 0.05 0.49 9% testing-user 0.05 0.02 249% Billy 0.10 0.29 33% SHARE: bob Username Usage(G) Quota(G) Quota(%) -------- -------- -------- -------- nobody 0.00 0.00 0% root 0.00 0.00 0% SHARE: more-shares-for-all Username Usage(G) Quota(G) Quota(%) -------- -------- -------- -------- Billy 0.10 0.00 0% testing-user 0.05 0.00 0% nobody 0.00 0.00 0% root 0.00 0.00 0% geoffro 0.05 0.00 0% SHARE: yep Username Usage(G) Quota(G) Quota(%) -------- -------- -------- -------- root 0.00 0.00 0% nobody 0.00 0.00 0% Billy 0.10 0.01 999% testing-user 0.05 0.49 9% geoffro 0.05 0.00 0%Project: default SHARE: Test-LUN SKIPPING Test-LUN - This is NOT a NFS or CIFs share, not looking for users SHARE: test-geoff Username Usage(G) Quota(G) Quota(%) -------- -------- -------- -------- geoffro 0.05 0.00 0% root 3.18 10.00 31% uucp 0.00 0.00 0% nobody 0.59 0.49 119%^CKilled by signal 2.Creating a WorkflowWorkflows are scripts that we store on the appliance, and can have the script execute either on request (even from the BUI), or on an event such as a threshold being met.Workflow BasicsA workflow allows you to create a simple process that can be executed either via the BUI interface interactively, or by an alert being raised (for some threshold being reached, for example).The basics parameters you will have to set for your "workflow object" (notice you're creating a variable, that embodies ECMAScript) are as follows (parameters is optional):name: A name for this workflowdescription: A Description for the workflowparameters: A set of input parameters (useful when you need user input to execute the workflow)execute: The code, the script itself to execute, which will be function (parameters)With parameters, you can specify things like this (slightly modified sample taken from the System Administration Guide): ...parameters: variableParam1: { label: 'Name of Share', type: 'String' }, variableParam2 { label: 'Share Size', type: 'size' },execute: ....}; Note the commas separating the sections of name, parameters, execute, and so on. This is important!Also - there is plenty of properties you can set on the parameters for your workflow, these are described in the Sun ZFS Storage System Administration Guide.Creating a Basic Workflow from a Basic ScriptTo make a basic script into a basic workflow, you need to wrap the following around your script to create a 'workflow' object:var workflow = {name: 'Get User Quotas',description: 'Displays Quota Utilisation for each user on each share',execute: function() {// (basic script goes here, minus the "script" at the beginning, and "." at the end)}};However, it appears (at least in my experience to date) that the workflow object may only be happy with one function in the execute parameter - either that or I'm doing something wrong. As far as I can tell, after execute: you should only have a basic one function context like so:execute: function(){}To deal with this, and to give an example similar to our script earlier, I have created another simple quota check, to show the same basic functionality, but in a workflow format:var workflow = {name: 'Get User Quotas',description: 'Displays Quota Utilisation for each user on each share',execute: function () { run('cd /'); run('shares'); projects=list(); for (i=0; i < projects.length; i++) { run('select ' + projects[i]); shares=list('filesystem'); printf("Project: %s\n", projects[i]); for(j=0; j < shares.length; j++) { run('select ' +shares[j]); try { run('users'); printf(" SHARE: %s\n", shares[j]); printf(" %20s %11s %11s %3s\n","Username","Usage(G)","Quota(G)","Quota(%)"); printf(" %20s %11s %11s %4s\n","--------","--------","--------","-------"); users=list(); for(k=0; k < users.length; k++) { run('select ' + users[k]); username=get('name'); usage=get('usage'); quota=get('quota'); usage_g=usage / 1073741824; // convert bytes to gigabytes quota_g=quota / 1073741824; // as above quota_percent=0 if (quota > 0) { quota_percent=(usage / quota)*(100/1); } printf(" %20s %8.2f %8.2f %d%%\n",username,usage_g,quota_g,quota_percent); run('done'); } run('done'); // exit user context } catch(err) { // printf(" %s is a LUN, Not looking for users\n", shares[j]); } run('done'); // exit selected share context } run('done'); // exit project context } }};SummaryThe Sun ZFS Storage 7000 Appliance offers lots of different and interesting features to Sun/Oracle customers, including the world renowned Analytics. Hopefully the above will help you to think of new creative things you could be doing by taking advantage of one of the other neat features, the internal scripting engine!Some references are below to help you continue learning more, I'll update this post as I do the same! Enjoy...More information on ECMAScript 3A complete reference to ECMAScript 3 which will help you learn more of the details you may be interested in, can be found here:http://www.ecma-international.org/publications/files/ECMA-ST-ARCH/ECMA-262,%203rd%20edition,%20December%201999.pdfMore Information on Administering the Sun ZFS Storage 7000The Sun ZFS Storage 7000 System Administration guide can be a useful reference point, and can be found here:http://wikis.sun.com/download/attachments/186238602/2010_Q3_2_ADMIN.pdf

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Steganography Experiment - Trouble hiding message bits in DCT coefficients

- by JohnHankinson

I have an application requiring me to be able to embed loss-less data into an image. As such I've been experimenting with steganography, specifically via modification of DCT coefficients as the method I select, apart from being loss-less must also be relatively resilient against format conversion, scaling/DSP etc. From the research I've done thus far this method seems to be the best candidate. I've seen a number of papers on the subject which all seem to neglect specific details (some neglect to mention modification of 0 coefficients, or modification of AC coefficient etc). After combining the findings and making a few modifications of my own which include: 1) Using a more quantized version of the DCT matrix to ensure we only modify coefficients that would still be present should the image be JPEG'ed further or processed (I'm using this in place of simply following a zig-zag pattern). 2) I'm modifying bit 4 instead of the LSB and then based on what the original bit value was adjusting the lower bits to minimize the difference. 3) I'm only modifying the blue channel as it should be the least visible. This process must modify the actual image and not the DCT values stored in file (like jsteg) as there is no guarantee the file will be a JPEG, it may also be opened and re-saved at a later stage in a different format. For added robustness I've included the message multiple times and use the bits that occur most often, I had considered using a QR code as the message data or simply applying the reed-solomon error correction, but for this simple application and given that the "message" in question is usually going to be between 10-32 bytes I have plenty of room to repeat it which should provide sufficient redundancy to recover the true bits. No matter what I do I don't seem to be able to recover the bits at the decode stage. I've tried including / excluding various checks (even if it degrades image quality for the time being). I've tried using fixed point vs. double arithmetic, moving the bit to encode, I suspect that the message bits are being lost during the IDCT back to image. Any thoughts or suggestions on how to get this working would be hugely appreciated. (PS I am aware that the actual DCT/IDCT could be optimized from it's naive On4 operation using row column algorithm, or an FDCT like AAN, but for now it just needs to work :) ) Reference Papers: http://www.lokminglui.com/dct.pdf http://arxiv.org/ftp/arxiv/papers/1006/1006.1186.pdf Code for the Encode/Decode process in C# below: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Drawing.Imaging; using System.Drawing; namespace ImageKey { public class Encoder { public const int HIDE_BIT_POS = 3; // use bit position 4 (1 << 3). public const int HIDE_COUNT = 16; // Number of times to repeat the message to avoid error. // JPEG Standard Quantization Matrix. // (to get higher quality multiply by (100-quality)/50 .. // for lower than 50 multiply by 50/quality. Then round to integers and clip to ensure only positive integers. public static double[] Q = {16,11,10,16,24,40,51,61, 12,12,14,19,26,58,60,55, 14,13,16,24,40,57,69,56, 14,17,22,29,51,87,80,62, 18,22,37,56,68,109,103,77, 24,35,55,64,81,104,113,92, 49,64,78,87,103,121,120,101, 72,92,95,98,112,100,103,99}; // Maximum qauality quantization matrix (if all 1's doesn't modify coefficients at all). public static double[] Q2 = {1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1}; public static Bitmap Encode(Bitmap b, string key) { Bitmap response = new Bitmap(b.Width, b.Height, PixelFormat.Format32bppArgb); uint imgWidth = ((uint)b.Width) & ~((uint)7); // Maximum usable X resolution (divisible by 8). uint imgHeight = ((uint)b.Height) & ~((uint)7); // Maximum usable Y resolution (divisible by 8). // Start be transferring the unmodified image portions. // As we'll be using slightly less width/height for the encoding process we'll need the edges to be populated. for (int y = 0; y < b.Height; y++) for (int x = 0; x < b.Width; x++) { if( (x >= imgWidth && x < b.Width) || (y>=imgHeight && y < b.Height)) response.SetPixel(x, y, b.GetPixel(x, y)); } // Setup the counters and byte data for the message to encode. StringBuilder sb = new StringBuilder(); for(int i=0;i<HIDE_COUNT;i++) sb.Append(key); byte[] codeBytes = System.Text.Encoding.ASCII.GetBytes(sb.ToString()); int bitofs = 0; // Current bit position we've encoded too. int totalBits = (codeBytes.Length * 8); // Total number of bits to encode. for (int y = 0; y < imgHeight; y += 8) { for (int x = 0; x < imgWidth; x += 8) { int[] redData = GetRedChannelData(b, x, y); int[] greenData = GetGreenChannelData(b, x, y); int[] blueData = GetBlueChannelData(b, x, y); int[] newRedData; int[] newGreenData; int[] newBlueData; if (bitofs < totalBits) { double[] redDCT = DCT(ref redData); double[] greenDCT = DCT(ref greenData); double[] blueDCT = DCT(ref blueData); int[] redDCTI = Quantize(ref redDCT, ref Q2); int[] greenDCTI = Quantize(ref greenDCT, ref Q2); int[] blueDCTI = Quantize(ref blueDCT, ref Q2); int[] blueDCTC = Quantize(ref blueDCT, ref Q); HideBits(ref blueDCTI, ref blueDCTC, ref bitofs, ref totalBits, ref codeBytes); double[] redDCT2 = DeQuantize(ref redDCTI, ref Q2); double[] greenDCT2 = DeQuantize(ref greenDCTI, ref Q2); double[] blueDCT2 = DeQuantize(ref blueDCTI, ref Q2); newRedData = IDCT(ref redDCT2); newGreenData = IDCT(ref greenDCT2); newBlueData = IDCT(ref blueDCT2); } else { newRedData = redData; newGreenData = greenData; newBlueData = blueData; } MapToRGBRange(ref newRedData); MapToRGBRange(ref newGreenData); MapToRGBRange(ref newBlueData); for(int dy=0;dy<8;dy++) { for(int dx=0;dx<8;dx++) { int col = (0xff<<24) + (newRedData[dx+(dy*8)]<<16) + (newGreenData[dx+(dy*8)]<<8) + (newBlueData[dx+(dy*8)]); response.SetPixel(x+dx,y+dy,Color.FromArgb(col)); } } } } if (bitofs < totalBits) throw new Exception("Failed to encode data - insufficient cover image coefficients"); return (response); } public static void HideBits(ref int[] DCTMatrix, ref int[] CMatrix, ref int bitofs, ref int totalBits, ref byte[] codeBytes) { int tempValue = 0; for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { if ( (u != 0 || v != 0) && CMatrix[v+(u*8)] != 0 && DCTMatrix[v+(u*8)] != 0) { if (bitofs < totalBits) { tempValue = DCTMatrix[v + (u * 8)]; int bytePos = (bitofs) >> 3; int bitPos = (bitofs) % 8; byte mask = (byte)(1 << bitPos); byte value = (byte)((codeBytes[bytePos] & mask) >> bitPos); // 0 or 1. if (value == 0) { int a = DCTMatrix[v + (u * 8)] & (1 << HIDE_BIT_POS); if (a != 0) DCTMatrix[v + (u * 8)] |= (1 << HIDE_BIT_POS) - 1; DCTMatrix[v + (u * 8)] &= ~(1 << HIDE_BIT_POS); } else if (value == 1) { int a = DCTMatrix[v + (u * 8)] & (1 << HIDE_BIT_POS); if (a == 0) DCTMatrix[v + (u * 8)] &= ~((1 << HIDE_BIT_POS) - 1); DCTMatrix[v + (u * 8)] |= (1 << HIDE_BIT_POS); } if (DCTMatrix[v + (u * 8)] != 0) bitofs++; else DCTMatrix[v + (u * 8)] = tempValue; } } } } } public static void MapToRGBRange(ref int[] data) { for(int i=0;i<data.Length;i++) { data[i] += 128; if(data[i] < 0) data[i] = 0; else if(data[i] > 255) data[i] = 255; } } public static int[] GetRedChannelData(Bitmap b, int sx, int sy) { int[] data = new int[8 * 8]; for (int y = sy; y < (sy + 8); y++) { for (int x = sx; x < (sx + 8); x++) { uint col = (uint)b.GetPixel(x,y).ToArgb(); data[(x - sx) + ((y - sy) * 8)] = (int)((col >> 16) & 0xff) - 128; } } return (data); } public static int[] GetGreenChannelData(Bitmap b, int sx, int sy) { int[] data = new int[8 * 8]; for (int y = sy; y < (sy + 8); y++) { for (int x = sx; x < (sx + 8); x++) { uint col = (uint)b.GetPixel(x, y).ToArgb(); data[(x - sx) + ((y - sy) * 8)] = (int)((col >> 8) & 0xff) - 128; } } return (data); } public static int[] GetBlueChannelData(Bitmap b, int sx, int sy) { int[] data = new int[8 * 8]; for (int y = sy; y < (sy + 8); y++) { for (int x = sx; x < (sx + 8); x++) { uint col = (uint)b.GetPixel(x, y).ToArgb(); data[(x - sx) + ((y - sy) * 8)] = (int)((col >> 0) & 0xff) - 128; } } return (data); } public static int[] Quantize(ref double[] DCTMatrix, ref double[] Q) { int[] DCTMatrixOut = new int[8*8]; for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { DCTMatrixOut[v + (u * 8)] = (int)Math.Round(DCTMatrix[v + (u * 8)] / Q[v + (u * 8)]); } } return(DCTMatrixOut); } public static double[] DeQuantize(ref int[] DCTMatrix, ref double[] Q) { double[] DCTMatrixOut = new double[8*8]; for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { DCTMatrixOut[v + (u * 8)] = (double)DCTMatrix[v + (u * 8)] * Q[v + (u * 8)]; } } return(DCTMatrixOut); } public static double[] DCT(ref int[] data) { double[] DCTMatrix = new double[8 * 8]; for (int v = 0; v < 8; v++) { for (int u = 0; u < 8; u++) { double cu = 1; if (u == 0) cu = (1.0 / Math.Sqrt(2.0)); double cv = 1; if (v == 0) cv = (1.0 / Math.Sqrt(2.0)); double sum = 0.0; for (int y = 0; y < 8; y++) { for (int x = 0; x < 8; x++) { double s = data[x + (y * 8)]; double dctVal = Math.Cos((2 * y + 1) * v * Math.PI / 16) * Math.Cos((2 * x + 1) * u * Math.PI / 16); sum += s * dctVal; } } DCTMatrix[u + (v * 8)] = (0.25 * cu * cv * sum); } } return (DCTMatrix); } public static int[] IDCT(ref double[] DCTMatrix) { int[] Matrix = new int[8 * 8]; for (int y = 0; y < 8; y++) { for (int x = 0; x < 8; x++) { double sum = 0; for (int v = 0; v < 8; v++) { for (int u = 0; u < 8; u++) { double cu = 1; if (u == 0) cu = (1.0 / Math.Sqrt(2.0)); double cv = 1; if (v == 0) cv = (1.0 / Math.Sqrt(2.0)); double idctVal = (cu * cv) / 4.0 * Math.Cos((2 * y + 1) * v * Math.PI / 16) * Math.Cos((2 * x + 1) * u * Math.PI / 16); sum += (DCTMatrix[u + (v * 8)] * idctVal); } } Matrix[x + (y * 8)] = (int)Math.Round(sum); } } return (Matrix); } } public class Decoder { public static string Decode(Bitmap b, int expectedLength) { expectedLength *= Encoder.HIDE_COUNT; uint imgWidth = ((uint)b.Width) & ~((uint)7); // Maximum usable X resolution (divisible by 8). uint imgHeight = ((uint)b.Height) & ~((uint)7); // Maximum usable Y resolution (divisible by 8). // Setup the counters and byte data for the message to decode. byte[] codeBytes = new byte[expectedLength]; byte[] outBytes = new byte[expectedLength / Encoder.HIDE_COUNT]; int bitofs = 0; // Current bit position we've decoded too. int totalBits = (codeBytes.Length * 8); // Total number of bits to decode. for (int y = 0; y < imgHeight; y += 8) { for (int x = 0; x < imgWidth; x += 8) { int[] blueData = ImageKey.Encoder.GetBlueChannelData(b, x, y); double[] blueDCT = ImageKey.Encoder.DCT(ref blueData); int[] blueDCTI = ImageKey.Encoder.Quantize(ref blueDCT, ref Encoder.Q2); int[] blueDCTC = ImageKey.Encoder.Quantize(ref blueDCT, ref Encoder.Q); if (bitofs < totalBits) GetBits(ref blueDCTI, ref blueDCTC, ref bitofs, ref totalBits, ref codeBytes); } } bitofs = 0; for (int i = 0; i < (expectedLength / Encoder.HIDE_COUNT) * 8; i++) { int bytePos = (bitofs) >> 3; int bitPos = (bitofs) % 8; byte mask = (byte)(1 << bitPos); List<int> values = new List<int>(); int zeroCount = 0; int oneCount = 0; for (int j = 0; j < Encoder.HIDE_COUNT; j++) { int val = (codeBytes[bytePos + ((expectedLength / Encoder.HIDE_COUNT) * j)] & mask) >> bitPos; values.Add(val); if (val == 0) zeroCount++; else oneCount++; } if (oneCount >= zeroCount) outBytes[bytePos] |= mask; bitofs++; values.Clear(); } return (System.Text.Encoding.ASCII.GetString(outBytes)); } public static void GetBits(ref int[] DCTMatrix, ref int[] CMatrix, ref int bitofs, ref int totalBits, ref byte[] codeBytes) { for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { if ((u != 0 || v != 0) && CMatrix[v + (u * 8)] != 0 && DCTMatrix[v + (u * 8)] != 0) { if (bitofs < totalBits) { int bytePos = (bitofs) >> 3; int bitPos = (bitofs) % 8; byte mask = (byte)(1 << bitPos); int value = DCTMatrix[v + (u * 8)] & (1 << Encoder.HIDE_BIT_POS); if (value != 0) codeBytes[bytePos] |= mask; bitofs++; } } } } } } } UPDATE: By switching to using a QR Code as the source message and swapping a pair of coefficients in each block instead of bit manipulation I've been able to get the message to survive the transform. However to get the message to come through without corruption I have to adjust both coefficients as well as swap them. For example swapping (3,4) and (4,3) in the DCT matrix and then respectively adding 8 and subtracting 8 as an arbitrary constant seems to work. This survives a re-JPEG'ing of 96 but any form of scaling/cropping destroys the message again. I was hoping that by operating on mid to low frequency values that the message would be preserved even under some light image manipulation.

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Content Box is a Little Off in IE9 ... How to Fix?

- by Kelsey Nealon

Hi there! I have a website at www.thetotempole.ca and when viewed in IE9... My websites content box (The green wooden backgrounded box with content inside) is moved slightly over to the left making a space between the actual container and the content box... Is there anyway I can fix this without harming any of the other browsers? Thanks! Screenshot: HTML: <!DOCTYPE html> <head> <title>The Totem Pole News - Movies</title>  <link rel="stylesheet" type="text/css" href="engine1/style.css" /> <script type="text/javascript" src="engine1/jquery.js"></script>  <script type="text/javascript"> var _gaq = _gaq || []; _gaq.push(['_setAccount', 'UA-45342007-1']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); </script> <meta charset="utf-8"> <meta name="description" content="A totem pole themed news website posting articles on news, music, movies, video games, and health."> <link href="thecss2.css" rel="stylesheet" type="text/css"> <link rel="icon" type="image/ico" href="images/favicon.ico"> <meta http-equiv="X-UA-Compatible" content="IE=8" /> </head> <body> <div id="container"> <div id="contentbox" align="Center"> <a href="index.html"><div id="banner" align="Center"> </div></a> <div id="navbar"> <p><a href="index.html"><img src="images/home.png" width="65" height="54" alt="picture of a house to relate to the home page (content)" style="position: absolute; left: 23px; top: 16px; width: 57px; height: 48px;"><span style="position: absolute; left: 24px; z-index:2; top: 71px; height: 23px;">Content</span></a> <a href="#"><img src="images/eagleicon.gif" width="73" height="39" alt="An Eagle icon for the News section of the Totem Pole" style="position: absolute; left: 111px; top: 28px;"><span style="position: absolute; z-index: 2; left: 127px; top: 72px;">News</span></a> <a href="#"><img src="images/owlicon.gif" width="81" height="61" alt="An Owl icon for the Music section of the totem pole" style="position: absolute; left: 210px; top: 11px;"><span style="position: absolute; z-index:2; left: 226px; top: 73px;"><strong>Music</strong></span></a><a href="movies.html"><img src="images/wolficon.gif" width="88" height="54" alt="A Wolf icon for the Movies section of the totem pole" style="position: absolute; left: 320px; top: 15px;"><span style="position: absolute; left: 336px; top: 72px; z-index:2;"><strong>Movies</strong></span></a> <a href="#"><img src="images/hareimage.gif" width="60" height="56" alt="A Hare icon for Video Game section of the Totem Pole" style="position: absolute; left: 441px; top: 13px;"><span style="position: absolute; z-index:2; left: 428px; top: 73px;"><strong>Video Games</strong></span></a> <a href="#"><img src="images/bearicon.gif" width="91" height="57" alt="A bear icon for the Health section of The Totem Pole" style="position: absolute; left: 551px; top: 13px;"><span style="position: absolute; left: 580px; top: 72px; z-index:2;">Health</span></a></p> </div>  <div id="navbar2"> <a href="#">About Us</a> <a href="#">Feedback</a> <a href="#">Subscribe</a> </div>  <div id="searchbar"> <form method="get" action="http://search.atomz.com/search/"> <input id="searchbox" size="13" name="sp_q" value="Search..." onFocus="if (this.value == 'Search...') {this.value=''}"> <input class="css_btn_class" type="submit" value="Search"> <input type="hidden" name="sp_a" value="sp1005092e"> <input type="hidden" name="sp_p" value="all"> <input type="hidden" name="sp_f" value="UTF-8"> </form> </div>  <div id="mywowslider"> <div id="wowslider-container1"> <div class="ws_images"> <ul> <li><img src="images/anchor.jpg" alt="Ron Burgundy" title="Ron Burgundy" id="wows1_0"/>Played by Will Ferrell</li> <li><img src="images/anchor2.jpg" alt="Brian Fantana" title="Brian Fantana" id="wows1_1"/>Played by Paul Rudd</li> <li><img src="images/anchor3.jpg" alt="Brick Tamland" title="Brick Tamland" id="wows1_2"/>Played by Steve Carrell</li> <li><img src="images/anchor4.jpg" alt="Champ Kind" title="Champ Kind" id="wows1_3"/>Played by David Koechner</li> </ul> </div> <div class="ws_bullets"><div> <a href="#" title="Ron Burgundy"><img src="images/anchor.jpg" alt="Ron Burgundy"/>1</a> <a href="#" title="Brian Fantana"><img src="images/anchor2.jpg" alt="Brian Fantana"/>2</a> <a href="#" title="Brick Tamland"><img src="images/anchor3.jpg" alt="Brick Tamland"/>3</a> <a href="#" title="Champ Kind"><img src="images/anchor4.jpg" alt="Champ Kind"/>4</a> </div> </div> <span class="wsl"><a href="http://wowslider.com"></a></span> <div class="ws_shadow"></div> </div> <script type="text/javascript" src="engine1/wowslider.js"></script> <script type="text/javascript" src="engine1/script.js"></script> </div>    <script type="text/javascript" src="//s7.addthis.com/js/300/addthis_widget.js#pubid=ra-5279b96309e7df24"></script> <script type="text/javascript"> addthis.layers({ 'theme' : 'transparent', 'share' : { 'position' : 'left', 'numPreferredServices' : 5 } }); </script>  <div id="sources"><p> Source(s): <a href="http://en.wikipedia.org/wiki/Anchorman_2:_The_Legend_Continues">wikipedia.com</a></p></div> <div id="infocontent"> <p align="left"><em><strong>       Anchorman 2: The Legend Continues</strong></em> is an upcoming American comedy film being released on December 20, 2013, also a sequel to the 2004 film <em>Anchorman: The Legend of Ron Burgandy</em>. On March 28, 2012, actor Will Ferrell officially announced the sequel dressed in character as Ron Burgundy on the late-night talk-show <em>Conan</em>. As with the original film, it is directed by Adam McKay, produced by Judd Apatow, stars Will Ferrell and is written by Adam McKay and Will Ferrell. Unlike the original film, which was distributed by DreamWorks Pictures, <em>The Legend Continues</em> will be distributed by Paramount Pictures.</p> <p align="left"><em><strong>      </strong></em>The movie now has a website at <a href="www.anchormanmovie.com">www.anchormanmovie.com</a> where a countdown for the release of this film can be seen. By the looks of these images, I think we can expect big things when the movie comes out this December. Enjoy the poster photos and trailers all posted below, and don't forget to submit your vote in the poll!</p> </div> <div id="trailer1"><iframe width="560" height="315" src="//www.youtube.com/embed/Elczv0ghqw0?rel=0" frameborder="0" allowfullscreen></iframe></div> <div id="trailer2"> <iframe width="560" height="315" src="//www.youtube.com/embed/mZ-JX-7B3uM?rel=0" frameborder="0" allowfullscreen></iframe> </div> <div id="poll"> <form method="post" action="http://poll.pollcode.com/763294"><table style="border: black 1px solid;" border="1" width="175" bgcolor="EEEEEE" cellspacing="2" cellpadding="0"><tr><td colspan="2" height="10"><font face="Verdana" size="2" color="000000"><b>What Rating Do You Think This Will Recieve</b></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="1" id="763294answer1"></td><td> <font face="Verdana" size="2" color="000000"><label for="763294answer1">10</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="2" id="763294answer2"></td><td> <font face="Verdana" size="2" color="000000"><label for="763294answer2">9</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="3" id="763294answer3"></td><td> <font face="Verdana" size="2" color="000000"><label for="763294answer3">8</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="4" id="763294answer4"></td><td> <font face="Verdana" size="2" color="000000"><label for="763294answer4">7</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="5" id="763294answer5"></td><td> <font face="Verdana" size="2" color="000000"><label for="763294answer5">6</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="6" id="763294answer6"></td><td> <font face="Verdana" size="2" color="000000"><label for="763294answer6">5</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="7" id="763294answer7"></td><td> <font face="Verdana" size="2" color="000000"><label for="763294answer7">4</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="8" id="763294answer8"></td><td> <font face="Verdana" size="2" color="000000"><label for="763294answer8">3</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="9" id="763294answer9"></td><td> <font face="Verdana" size="2" color="000000"><label for="763294answer9">2</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="10" id="763294answer10"></td><td> <font face="Verdana" size="2" color="000000"><label for="763294answer10">1</label></font></td></tr><tr><td colspan="2" height="10"><center><input type="submit" value=" Vote ">  <input title="Clicking this will send you to a new page" type="submit" name="view" value=" View "></center></td></tr><tr><td colspan="2" align="right"><font face="Verdana" height="5" size="1" color="000000"></font></td></tr></table></form></div> <span style="position: absolute; left: 0px; top: 225px; width: 1000px; border-bottom: 2px black double; height: 58px;"> <h1 style="font-weight: normal; font-size:28px"><em>Anchorman 2 Arrives Soon</em></h1></span> <div id="contentbox2"></div>  <center><div id="footer"><a href="#">Sitemap</a> <a href="#">About Us</a> <a href="#">Feedback</a></div></center> <div id="disqus"><div id="disqus_thread"></div> <script type="text/javascript"> /* * * CONFIGURATION VARIABLES: EDIT BEFORE PASTING INTO YOUR WEBPAGE * * */ var disqus_shortname = 'thetotempoleanchorman2'; // required: replace example with your forum shortname /* * * DON'T EDIT BELOW THIS LINE * * */ (function() { var dsq = document.createElement('script'); dsq.type = 'text/javascript'; dsq.async = true; dsq.src = '//' + disqus_shortname + '.disqus.com/embed.js'; (document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(dsq); })(); </script> <noscript>Please enable JavaScript to view the <a href="http://disqus.com/?ref_noscript">comments powered by Disqus.</a></noscript> <a href="http://disqus.com" class="dsq-brlink">comments powered by <span class="logo-disqus">Disqus</span></a></div> </div>  </div> </body> </html> CSS: html { background: url(images/pine.jpg) no-repeat center center fixed; 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