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• Ultrawingrid - how to display #1/1/1800# as blank ( as if null )

  - by Charles Hankey

  Ultrawingrid 9.2 VS2008 .net 3.5 My wingrid uses a bindingsource. All datetimes which are null in SQL Server are delivered to the bindingsource as #1/1/1800# I would like Ultrawingrid to display this date as blank as it would a null from source. Also, if the date is null in the grid ( i.e. blanked out ) I would like to update the data source to the date #1/1/1800# ( the framework takes care of getting that date back into the backend as a null ) This seems like it should be a trivial matter but I can find no documentation on just where to intervene so the grid will see a particular date as a null and save a null as a particular date. This is the direction I've been headed but I don't think either is the right place and I can't even get the syntax to work in the BeforeRowUpdate as I cannot see how to set a value that is passed to the data binding without setting the value of control itself, which I think has to remain null in order to display as blank Private Sub ugPropMaster_BeforeRowUpdate(ByVal sender As Object, ByVal e As _ Infragistics.Win.UltraWinGrid.CancelableRowEventArgs) Handles _ ugPropMaster.BeforeRowUpdate If e.Row.Cells.Item("Exdate").Value Is Nothing Then e.Row.Cells("Exdate").Value = CDate(#1/1/1800#) End If End Sub Private Sub ugPropMaster_InitializeRow(ByVal sender As Object, ByVal e As _ Infragistics.Win.UltraWinGrid.InitializeRowEventArgs) Handles _ ugPropMaster.InitializeRow If CDate(e.Row.Cells.Item("Exdate").Value) = CDate(#1/1/1800#) Then e.Row.Cells.Item("Exdate").Value = Nothing End If End Sub Guidance much appreciated

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• When to use "property" builtin: auxiliary functions and generators

  - by Seth Johnson

  I recently discovered Python's property built-in, which disguises class method getters and setters as a class's property. I'm now being tempted to use it in ways that I'm pretty sure are inappropriate. Using the property keyword is clearly the right thing to do if class A has a property _x whose allowable values you want to restrict; i.e., it would replace the getX() and setX() construction one might write in C++. But where else is it appropriate to make a function a property? For example, if you have class Vertex(object): def __init__(self): self.x = 0.0 self.y = 1.0 class Polygon(object): def __init__(self, list_of_vertices): self.vertices = list_of_vertices def get_vertex_positions(self): return zip( *( (v.x,v.y) for v in self.vertices ) ) is it appropriate to add vertex_positions = property( get_vertex_positions ) ? Is it ever ok to make a generator look like a property? Imagine if a change in our code meant that we no longer stored Polygon.vertices the same way. Would it then be ok to add this to Polygon? @property def vertices(self): for v in self._new_v_thing: yield v.calculate_equivalent_vertex()

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• How can I draw on JPanel using another quadrant for the coordinates?

  - by Sanoj

  I would like to draw some shapes on a JPanel by overriding paintComponent. I would like to be able to pan and zoom. Panning and zooming is easy to do with AffineTransform and the setTransform method on the Graphics2D object. After doing that I can easyli draw the shapes with g2.draw(myShape) The shapes are defined with the "world coordinates" so it works fine when panning and I have to translate them to the canvas/JPanel coordinates before drawing. Now I would like to change the quadrant of the coordinates. From the 4th quadrant that JPanel and computer often uses to the 1st quadrant that the users are most familiar with. The X is the same but the Y-axe should increase upwards instead of downwards. It is easy to redefine origo by new Point(origo.x, -origo.y); But How can I draw the shapes in this quadrant? I would like to keep the coordinates of the shapes (defined in the world coordinates) rather than have them in the canvas coordinates. So I need to transform them in some way, or transform the Graphics2D object, and I would like to do it efficiently. Can I do this with AffineTransform too?

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• How to pass parameters to manage_shared_memory.construct() in Boost.Interprocess

  - by recipriversexclusion

  I've stared at the Boost.Interprocess documentation for hours but still haven't been able to figure this out. In the doc, they have an example of creating a vector in shared memory like so: //Define an STL compatible allocator of ints that allocates from the managed_shared_memory. //This allocator will allow placing containers in the segment typedef allocator<int, managed_shared_memory::segment_manager> ShmemAllocator; //Alias a vector that uses the previous STL-like allocator so that allocates //its values from the segment typedef vector<int, ShmemAllocator> MyVector; int main(int argc, char *argv[]) { //Create a new segment with given name and size managed_shared_memory segment(create_only, "MySharedMemory", 65536); //Initialize shared memory STL-compatible allocator const ShmemAllocator alloc_inst (segment.get_segment_manager()); //Construct a vector named "MyVector" in shared memory with argument alloc_inst MyVector *myvector = segment.construct<MyVector>("MyVector")(alloc_inst); Now, I understand this. What I'm stuck is how to pass a second parameter to segment.construct() to specify the number of elements. The interprocess document gives the prototype for construct() as MyType *ptr = managed_memory_segment.construct<MyType>("Name") (par1, par2...); but when I try MyVector *myvector = segment.construct<MyVector>("MyVector")(100, alloc_inst); I get compilation errors. My questions are: Who actually gets passed the parameters par1, par2 from segment.construct, the constructor of the object, e.g. vector? My understanding is that the template allocator parameter is being passed. Is that correct? How can I add another parameter, in addition to alloc_inst that is required by the constructor of the object being created in shared memory? There's very little information other than the terse Boost docs on this.

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• HTTPSConnection module missing in Python 2.6 on CentOS 5.2

  - by d2kagw

  Hi guys, I'm playing around with a Python application on CentOS 5.2. It uses the Boto module to communicate with Amazon Web Services, which requires communication through a HTTPS connection. When I try running my application I get an error regarding HTTPSConnection being missing: "AttributeError: 'module' object has no attribute 'HTTPSConnection'" Google doesn't really return anything relevant, I've tried most of the solutions but none of them solve the problem. Has anyone come across anything like it? Here's the traceback: Traceback (most recent call last): File "./chatter.py", line 114, in <module> sys.exit(main()) File "./chatter.py", line 92, in main chatter.status( ) File "/mnt/application/chatter/__init__.py", line 161, in status cQueue.connect() File "/mnt/application/chatter/tools.py", line 42, in connect self.connection = SQSConnection(cConfig.get("AWS", "KeyId"), cConfig.get("AWS", "AccessKey")); File "/usr/local/lib/python2.6/site-packages/boto-1.7a-py2.6.egg/boto/sqs/connection.py", line 54, in __init__ self.region.endpoint, debug, https_connection_factory) File "/usr/local/lib/python2.6/site-packages/boto-1.7a-py2.6.egg/boto/connection.py", line 418, in __init__ debug, https_connection_factory) File "/usr/local/lib/python2.6/site-packages/boto-1.7a-py2.6.egg/boto/connection.py", line 189, in __init__ self.refresh_http_connection(self.server, self.is_secure) File "/usr/local/lib/python2.6/site-packages/boto-1.7a-py2.6.egg/boto/connection.py", line 247, in refresh_http_connection connection = httplib.HTTPSConnection(host) AttributeError: 'module' object has no attribute 'HTTPSConnection'

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• Why would delaying a thread response fix view corruption?

  - by Beth S

  6 times out of 10 my very simple iPhone app is getting a corrupted display on launch or crashes randomly. But it behaves fine in the simulator. The display corruption looks like mis-colored fonts, out of place font text, wrong background colors, etc. I've found a strange work-around.. when my thread delays by 2 seconds before calling the "done" notification, everything works swimmingly. The thread reads a web page and the "done" notification loads up a PickerView with strings. So what gives? Can I not safely initiate a threaded task from viewDidLoad? - (void) loadWebPage:(NSString *)urlAddition { NSAutoreleasePool *subPool = [[NSAutoreleasePool alloc] init]; NSString *pageSource; NSError *err; NSString *urlString = [NSString stringWithString:@"http://server/%@", urlAddition]; pageSource = [NSString stringWithContentsOfURL:[NSURL URLWithString: urlString] encoding:NSUTF8StringEncoding error:&err]; [NSThread sleepForTimeInterval:2.0]; // THIS STOPS THE DISPLAY CORRUPTION [[NSNotificationCenter defaultCenter] postNotificationName:@"webDoneNotification" object:nil]; [subPool drain]; } - (void) webDoneNotification: (NSNotification *)pNotification { [mediaArray release]; mediaArray = [[NSArray arrayWithObjects: [NSString stringWithString:@"new pickerview text"], nil] retain]; [mediaPickerView reloadAllComponents]; [mediaPickerView selectRow:0 inComponent:0 animated:NO]; } - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { mediaArray = [[NSArray arrayWithObjects: [NSString stringWithString:@"init pickerview text"], nil] retain]; if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) { // Custom initialization } return self; } - (void)viewDidLoad { [super viewDidLoad]; myWebThread = [[WebThread alloc] initWithDelegate:self]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(webDoneNotification:) name:@"webDoneNotification" object:nil]; [myWebThread performSelectorInBackground:@selector(loadWebPage:) withObject:@""]; } Thanks! Update: Even a delay of 0.1 seconds is enough to completely fix the problem.

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• Writing language converter in ANTLR

  - by Stefan

  I'm writing a converter between some dialects of the same programming language. I've found a grammar on the net - it's complex and handles all the cases. Now I'm trying to write the appropriate actions. Most of the input is just going to be rewritten to output. What I need to do is parse function calls, do my magic (rename function, reorder arguments, etc) and write it. I'm using AST as output. When I come across a function call, I build a custom object structure (from classes defined in my target language), call the appropriate function and I have a string that represents the transformed function that I want to get. The problem is, what I'm supposed to do with that string? I'd like to replace the .text attribute of the enclosing rule, but setText() is only available on lexer rules and the rule's .text attribute is read-only. How to solve this problem? program : statement_list { output = $statement_list.text; } ; //... statement : expression_statement // ... ; expression_statement : function_call // ... ; function_call : ID '(' { /* build the object, assign name */ Function function = new Function(); //... } ( arg1 = expression { /* add first parameter */ } ( ',' arg2 = expression { /* add the rest of parameters */ } )* )? ')' { /* convert the function call */ string converted = Tools.Convert(function); // $setText(converted); // doesn't work // $functionCall.text = converted; // doesn't work } ;

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• Represent multiple Null/Generic objects in an ActiveRecord association?

  - by slothbear

  I have a Casefile model that belongs_to a Doctor. In additional to all the "real" doctors, there are several generic Doctors: "self-treated", "not specified", and "removed" (it used to have a real doctor, but no longer does). I suspect there will be even more generic values in the future. I started with special "doctors" in the database, generated from seed. The generic Doctors only need to respond to the "name" and "real_doctor?" methods. This worked with one, was strained with two, and now feels completely broken. I want to change the behavior and can't figure out how to test it, a bad sign. Creating all the generic objects for testing is also trouble, including fake values to pass validation of the required Doctor attributes. The Null Object pattern works well for one generic object. The "name" method could check casefile.doctor.nil? and return "self-treated", as demonstrated by Craig Ambrose. What pattern should I use when there are multiple generic objects with very limited state?

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• APS.NET MVC Ajax: Passing a IList from the View to the Controller

  - by Bpimenta

  I need to pass the grid rows from the view to the controller using POST. The idea is to pass an IList of objects (people) that have the following structure: String Name String Address String ID I want to read the data from the JQGrid and pass it to the controller to fill the IList. I'm trying to build the data object to pass through the Ajax data parameter. Here is the Javascript code: $("#saveButton").click( function() { var returnData = '{'; var existingIDs = $('#listPeople').getDataIDs(); if (idsPeople.length > 0) { for (i=0;i<idsPeople.length;i++) { //Trying to build the obejct data ret = ret + '"people['+ i +'].Name":' $('#listPeople').getRowData(idsPeople[i]).Name + ','; ret = ret + '"people['+ i +'].Address":' $('#listPeople').getRowData(idsPeople[i]).Address+ ','; ret = ret + '"people['+ i +'].Id":' $('#listPeople').getRowData(idsPeople[i]).Id+ ','; //If it has more than one element if (idsPeople.length>1 && (i+1)<idsPeople.length) { ret = ret + ','; } } } ret = ret + '}'; My Ajax function for sending: var url_all = '<%=Url.Action("SaveData") %>; $.ajax({ type: "POST", url: url_all, data: ret, dataType: "json", success: function(){ alert("OK"); }, error: function(){ alert("Error: check SaveData"); } }); My controller: public ActionResult SaveData(IList<PeopleHeader> people){ // using debug to know if "people" variable has any values return Json(true); } The problem I'm getting is an error: "System.NotSupportedException: Fixed size collection", and no data is being delivered. I think my problem relies on creating the object... is there any simpler way of doing this procedure? Thanks in advance,

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• .NET out of memory troubleshooting

  - by bushman

  After reading a few enlightening articles about memory in the .NET technology, Out of Memory does not refer to physical memory, 597499. I thought I understood why a C# app would throw an out of memory exception -- until I started experimenting with two servers-- both are having 2.5 gigs of ram, windows server 2003 and identical programs running. The only significant difference between the two being one has 7% hard drive storage left and the other more than 50%. The server with 7% storage space left is consistently throwing an out of memory while the other is performing consistently well. My app is a C# web application that process' hundreds of MBs of String object. Why would this difference happen seeing that the most likely reason for the out of memory issue is out of contiguous virtual address space -- What solutions do you guys propose -- and what do you say about the following 1. turn on the 3gb switch to increase the virtual address space -- 2. instead of using one giant string object, break it up into smaller pieces and collect it in a jagged array (here I have to find a way to return to the caller in some other way as right now, the return type is a string) thanks SO

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• To what degree should I use Marshal.ReleaseComObject with Excel Interop objects?

  - by DanM

  I've seen several examples where Marshal.ReleaseComObject() is used with Excel Interop objects (i.e., objects from namespace Microsoft.Office.Interop.Excel), but I've seen it used to various degrees. I'm wondering if I can get away with something like this: var application = new ApplicationClass(); try { // do work with application, workbooks, worksheets, cells, etc. } finally { Marashal.ReleaseComObject(application) } Or if I need to release every single object created, as in this method: public void CreateExcelWorkbookWithSingleSheet() { var application = new ApplicationClass(); var workbook = application.Workbooks.Add(_missing); var worksheets = workbook.Worksheets; for (var worksheetIndex = 1; worksheetIndex < worksheets.Count; worksheetIndex++) { var worksheet = (WorksheetClass)worksheets[worksheetIndex]; worksheet.Delete(); Marshal.ReleaseComObject(worksheet); } workbook.SaveAs( WorkbookPath, _missing, _missing, _missing, _missing, _missing, XlSaveAsAccessMode.xlExclusive, _missing, _missing, _missing, _missing, _missing); workbook.Close(true, _missing, _missing); application.Quit(); Marshal.ReleaseComObject(worksheets); Marshal.ReleaseComObject(workbook); Marshal.ReleaseComObject(application); } What prompted me to ask this question is that, being the LINQ devotee I am, I really want to do something like this: var worksheetNames = worksheets.Cast<Worksheet>().Select(ws => ws.Name); ...but I'm concerned I'll end up with memory leaks or ghost processes if I don't release each worksheet (ws) object. Any insight on this would be appreciated.

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• undefined references

  - by Brandon

  Hello, I'm trying to compile some fortran code and I'm running into some confusing linking errors. I have some code that I compile and place into a static library: >gfortran -c -I../../inc -o bdout.o bdout.F >ar rv libgeo.a bdout.o I then try to compile against that library with some simple test code and get the following: >gfortran -o mytest -L -lgeo mytest.F /tmp/cc4uvcsj.o: In function `MAIN__': mytest.F:(.text+0xb0): undefined reference to `ncwrite1_' collect2: ld returned 1 exit status It's not in the object naming because everything looks fine: >nm -u libgeo.a bdout.o: U _gfortran_exit_i4 U _gfortran_st_write U _gfortran_st_write_done U _gfortran_transfer_character U _gfortran_transfer_integer U ncobjcl_ U ncobjwrp_ U ncopencr_ U ncopenshcr_ U ncopenwr_ U ncwrite1_ U ncwrite2_ U ncwrite3_ U ncwrite4_ U ncwritev_ I can check the original object file too: >nm -u bdout.o U _gfortran_exit_i4 U _gfortran_st_write U _gfortran_st_write_done U _gfortran_transfer_character U _gfortran_transfer_integer U ncobjcl_ U ncobjwrp_ U ncopencr_ U ncopenshcr_ U ncopenwr_ U ncwrite1_ U ncwrite2_ U ncwrite3_ U ncwrite4_ U ncwritev_ The test code simply contains a single call to a function defined in bdout.o: program hello print *,"Hello World!" call ncwrite1( istat, f, ix2, ix3, ix4, ix5, ih ) end program hello I can't figure out what the problem is. Does anyone have any suggestions? Maybe even just a way to track the problem down? Cheers.

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• OpenCV shape matching

  - by MAckerman

  I'm new to OpenCV (am actually using Emgu CV C# wrapper) and am attempting to do some object detection. I'm attempting to determine if an object matches a predefined set of objects (that I will have to define). The background is well lit and does not move. My objects that I am starting with are bottles and cans. My current approach is: Do absDiff with a previously taken background image to separate the background. Then dilate 4x to make the lighter areas (in labels) shrink. Then I do a binary threshold to get a big blog, followed by finding contours in this image. I then take the largest contour and draw it, which becomes my shape to either save to the accepted set or compare with the accepted set. Currently I'm using cvMatchShapes, but the double return value seems to vary widely. I'm guessing it is because it doesn't take into account rotation. Is this approach a good one? It isn't working well for glass bottles since the edges are hard to find... I've read about haar classifiers, but thinking that might be overkill for my task.

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• Complex derived attributes in Django models

  - by rabidpebble

  What I want to do is implement submission scoring for a site with users voting on the content, much like in e.g. reddit (see the 'hot' function in http://code.reddit.com/browser/sql/functions.sql). My submission model currently keeps track of up and down vote totals. Currently, when a user votes I create and save a related Vote object and then use F() expressions to update the Submission object's voting totals. The problem is that I want to update the score for the submission at the same time, but F() expressions are limited to only simple operations (it's missing support for log(), date_part(), sign() etc.) From my limited experience with Django I can see 4 options here: extend F() somehow (haven't looked at the code yet) to support the missing SQL functions; this is my preferred option and seems to fit within the Django framework the best define a scoring function (much like reddit's 'hot' function) in my database, and have Django use the value of that function for the value of the score field; as far as I can tell, #2 is not possible wrap my two step voting process in a suitably isolated transaction so that I can calculate the voting totals in Python and then update the Submission's voting totals without fear that another vote against the submission could be added/changed in the meantime; I'm hesitant to take this route because it seems overly complex - what is a "suitably isolated transaction" in this case anyway? use raw SQL; I would prefer to avoid this entirely -- what's the point of an ORM if I have to revert to SQL for such a common use case as this! (Note that this coming from somebody who loves sprocs, but is using Django for ease of development.) Before I embark on this mission to extend F() (which I'm not sure is even possible), am I about to reinvent the wheel? Is there a more standard way to do this? It seems like such a common use case and yet in an hour of searching I have yet to find a common solution...

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• Passing youtube video id from video feed to flash

  - by Grant Anderson

  I'm working on a flash web application (Actionscript 2.0) for my honours project but am having trouble embedding youtube videos. Basically the user selects symbols which queries the youtube api with certain tags depending on the symbols chosenand a random video is then picked from the first 30 videos. I have this working using the following code: on (release) { url="http://gdata.youtube.com/feeds/api/videos?q=danger+passion&orderby=published&start-index="+random(30)+"&max-results=1&v=2" getURL(url); } but this just displays a webpage with a link to the youtube video. This is the code I'll be using as the foundations for the player: // create a MovieClip to load the player into var ytplayer:MovieClip = _root.createEmptyMovieClip("ytplayer", 1); // create a listener object for the MovieClipLoader to use var ytPlayerLoaderListener:Object = { onLoadInit: function() { // When the player clip first loads, we start an interval to // check for when the player is ready loadInterval = setInterval(checkPlayerLoaded, 250); } }; var loadInterval:Number; function checkPlayerLoaded():Void { // once the player is ready, we can subscribe to events, or in the case of // the chromeless player, we could load videos if (ytplayer.isPlayerLoaded()) { ytplayer.addEventListener("onStateChange", onPlayerStateChange); ytplayer.addEventListener("onError", onPlayerError); clearInterval(loadInterval); } } function onPlayerStateChange(newState:Number) { trace("New player state: "+ newState); } function onPlayerError(errorCode:Number) { trace("An error occurred: "+ errorCode); } // create a MovieClipLoader to handle the loading of the player var ytPlayerLoader:MovieClipLoader = new MovieClipLoader(); ytPlayerLoader.addListener(ytPlayerLoaderListener); // load the player ytPlayerLoader.loadClip("http://www.youtube.com/v/pv5zWaTEVkI", ytplayer); can anyone help me on how to get the id of the video (for example: pv5zWaTEVkI) from the feed? Or how to send a query from flash which will return the video url/id as opposed to the url of a feed. Any help would be much appreciated as my hand in rather soon. Thanks

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• LotusScript - Setting element in for loop

  - by Kris.Mitchell

  I have an array set up Dim managerList(1 To 50, 1 To 100) As String what I am trying to do, is set the first, second, and third elements in the row managerList(index,1) = tempManagerName managerList(index,2) = tempIdeaNumber managerList(index,3) = 1 But get an error when I try to do that saying that the object variable is not set. I maintain index as an integer, and the value corresponds to a single manager, but I can't seem to manually set the third element. The first and second elements set correctly. On the flip side, I have the following code that will allow for the element to be set, For x=1 To 50 If StrConv(tempManagerName,3) = managerList(x,1) Then found = x For y=3 to 100 If managerList(x,y) = "" Then managerList(x,y) = tempIdeaNumber Exit for End If Next Exit For End If Next It spins through the array (laterally) trying to find an empty element. Ideally I would like to set the index of the element the y variable is on into the 3rd element in the row, to keep a count of how many ideas are on the row. What is the best way to keep a count like this? Any idea why I am getting a Object variable not set error when I try to manually set the element?

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• How are Scala closures transformed to Java objects?

  - by iguana

  I'm currently looking at closure implementations in different languages. When it comes to Scala, however, I'm unable to find any documentation on how a closure is mapped to Java objects. It is well documented that Scala functions are mapped to FunctionN objects. I assume that the reference to the free variable of the closure must be stored somewhere in that function object (as it is done in C++0x, e.g.). I also tried compiling the following with scalac and then decompiling the class files with JD: object ClosureExample extends Application { def addN(n: Int) = (a: Int) => a + n var add5 = addN(5) println(add5(20)) } In the decompiled sources, I see an anonymous subtype of Function1, which ought to be my closure. But the apply() method is empty, and the anonymous class has no fields (which could potentially store the closure variables). I suppose the decompiler didn't manage to get the interesting part out of the class files... Now to the questions: Do you know how the transformation is done exactly? Do you know where it is documented? Do you have another idea how I could solve the mystery?

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• Why is my html getting mal-formed?

  - by alkaloids

  I have the following table in a form that's embedded in a formtastic form (semantic_form_for). Everything I ask to be generated by ruby shows up, but the table gets badly mangled (essentially, the tags NEVER get formed. The table headers get drawn correctly There are 14 available_date objects that get passed, and they alternate between having a time value of 1 or 2, so this is just terribly boggling, but probably simple to fix... <table class="availability_table"> <tr> <th>Date</th> <th>Early</th> <th>Late</th> </tr> <% f.fields_for :available_dates do |ad| %> <% if ad.object.time == 1 #if this is an early shift, then start the new row %> <tr><td><%= ad.object.date.strftime('%a, %b %d, %Y') %></td> <td><%= ad.collection_select(:availability , LookupAvailability.all.collect, :id, :name) %></td> <% else #otherwise end the row with just a box%> <td><%= ad.collection_select(:availability , LookupAvailability.all.collect, :id, :name) %></td></tr> <% end %> <% end %> </table> So like I said, the form functions properly, and the objects all get updated and displayed correctly and all that, it's just that the HTML isn't getting echo'd out properly so my table is all mangled. Help!

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• NHibernate: how to handle entity-based validation using session-per-request pattern, without control

  - by Seth Petry-Johnson

  What is the best way to do entity-based validation (each entity class has an IsValid() method that validates its internal members) in ASP.NET MVC, with a "session-per-request" model, where the controller has zero (or limited) knowledge of the ISession? Here's the pattern I'm using: Get an entity by ID, using an IFooRepository that wraps the current NH session. This returns a connected entity instance. Load the entity with potentially invalid data, coming from the form post. Validate the entity by callings its IsValid() method. If valid, call IFooRepository.Save(entity). Otherwise, display error message. The session is currently opened when the request begins and flushed when the request ends. Since my entity is connected to a session, flushing the session attempts to save the changes even if the object is invalid. What's the best way to keep validation logic in the entity class, limit controller knowledge of NH, and avoid saving invalid changes at the end of a request? Option 1: Explicitly evict on validation failure, implicitly flush: if the validation fails, I could manually evict the invalid object in the action method. If successful, I do nothing and the session is automatically flushed. Con: error prone and counter-intuitive ("I didn't call .Save(), why are my invalid changes being saved anyways?") Option 2: Explicitly flush, do nothing by default: By default I can dispose of the session on request end, only flushing if the controller indicates success. I'd probably create a SaveChanges() method in my base controller that sets a flag indicating success, and then query this flag when closing the session at request end. Pro: More intuitive to troubleshoot if dev forgets this step [relative to option 1] Con: I have to call IRepository.Save(entity)' and SaveChanges(). Option 3: Always work with disconnected objects: I could modify my repositories to return disconnected/transient objects, and modify the Repo.Save() method to re-attach them. Pro: Most intuitive, given that controllers don't know about NH. Con: Does this defeat many of the benefits I'd get from NH?

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• How can I automatically release resources RAII-style in Perl?

  - by Philip Potter

  Say I have a resource (e.g. a filehandle or network socket) which has to be freed: open my $fh, "<", "filename" or die "Couldn't open filename: $!"; process($fh); close $fh or die "Couldn't close filename: $!"; Suppose that process might die. Then the code block exits early, and $fh doesn't get closed. I could explicitly check for errors: open my $fh, "<", "filename" or die "Couldn't open filename: $!"; eval {process($fh)}; my $saved_error = $@; close $fh or die "Couldn't close filename: $!"; die $saved_error if $saved_error; but this kind of code is notoriously difficult to get right, and only gets more complicated when you add more resources. In C++ I would use RAII to create an object which owns the resource, and whose destructor would free it. That way, I don't have to remember to free the resource, and resource cleanup happens correctly as soon as the RAII object goes out of scope - even if an exception is thrown. Unfortunately in Perl a DESTROY method is unsuitable for this purpose as there are no guarantees for when it will be called. Is there a Perlish way to ensure resources are automatically freed like this even in the presence of exceptions? Or is explicit error checking the only option?

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• Is this an example of LINQ-to-SQL?

  - by Edward Tanguay

  I made a little WPF application with a SQL CE database. I built the following code with LINQ to get data out of the database, which was surprisingly easy. So I thought "this must be LINQ-to-SQL". Then I did "add item" and added a "LINQ-to-SQL classes" .dbml file, dragged my table onto the Object Relational Designer but it said, "The selected object uses an unsupported data provider." So then I questioned whether or not the following code actually is LINQ-to-SQL, since it indeed allows me to access data from my SQL CE database file, yet officially "LINQ-to-SQL" seems to be unsupported for SQL CE. So is the following "LINQ-to-SQL" or not? using System.Linq; using System.Data.Linq; using System.Data.Linq.Mapping; using System.Windows; namespace TestLinq22 { public partial class Window1 : Window { public Window1() { InitializeComponent(); MainDB db = new MainDB(@"Data Source=App_Data\Main.sdf"); var customers = from c in db.Customers select new {c.FirstName, c.LastName}; TheListBox.ItemsSource = customers; } } [Database(Name = "MainDB")] public class MainDB : DataContext { public MainDB(string connection) : base(connection) { } public Table<Customers> Customers; } [Table(Name = "Customers")] public class Customers { [Column(DbType = "varchar(100)")] public string FirstName; [Column(DbType = "varchar(100)")] public string LastName; } }

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• How can I add a plugin to the registry while using a Zend_Form?

  - by Mallika Iyer

  I have a zend form that I'm initializing as follows: $form = new Form_XYZ(); I have a display group in that form, which I'm calling like this: $form->addDisplayGroup($generalSettingsGroup, 'general', array( 'legend' => 'General', 'disableDefaultDecorators' => true, 'decorators' => array( 'FormElements', 'FieldSet', array('HtmlTag', array('tag' => 'div', 'class' => 'general') ) ) ) ); I get this error : ArrayObject Object ( [exception] => Zend_Loader_PluginLoader_Exception Object ( [message:protected] => Plugin by name 'FieldSet' was not found in the registry; used paths:Zend_Form_Decorator_: Zend/Form/Decorator/ [string:private] => [code:protected] => 0 [file:protected] => /usr/share/pear/PEAR/Zend/Loader/PluginLoader.php [line:protected] => 406 [trace:private] => Array ................... How can I add the FieldSet plugin to the registry? I'm using the default Zend_Form Fieldset decorator.

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• Caching sitemaps in django

  - by michuk

  I implemented a simple sitemap class using django's default sitemap app. As it was taking a long time to execute, I added manual caching: class ShortReviewsSitemap(Sitemap): changefreq = "hourly" priority = 0.7 def items(self): # try to retrieve from cache result = get_cache(CACHE_SITEMAP_SHORT_REVIEWS, "sitemap_short_reviews") if result!=None: return result result = ShortReview.objects.all().order_by("-created_at") # store in cache set_cache(CACHE_SITEMAP_SHORT_REVIEWS, "sitemap_short_reviews", result) return result def lastmod(self, obj): return obj.updated_at The problem is that memcache allows only max 1MB object. This one was bigger that 1MB, so storing into cache failed: >7 SERVER_ERROR object too large for cache The problem is that django has an automated way of deciding when it should divide the sitemap file into smalled ones. According to the docs (http://docs.djangoproject.com/en/dev/ref/contrib/sitemaps/): You should create an index file if one of your sitemaps has more than 50,000 URLs. In this case, Django will automatically paginate the sitemap, and the index will reflect that. What do you think would be the best way to enable caching sitemaps? - Hacking into django sitemaps framework to restrict a single sitemap size to, let's say, 10,000 records seems like the best idea. Why was 50,000 chosen in the first place? Google advice? random number? - Or maybe there is a way to allow memcached store bigger files? - Or perhaps onces saved, the sitemaps should be made available as static files? This would mean that instead of caching with memcached I'd have to manually store the results in the filesystem and retrieve them from there next time when the sitemap is requested (perhaps cleaning the directory daily in a cron job). All those seem very low level and I'm wondering if an obvious solution exists...

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• NotFoundException in layout editor for Android?

  - by borg17of20

  I'm trying to extend a RelativeLayout object and include an embedded SurfaceView object that uses a png file in my /res/drawable folder as its background but I keep getting an error in the XML Layout editor. See the following code: public class StopMotionRelativeLayout extends RelativeLayout { private Context myContext; private SurfaceView surfaceView1; private BitmapFactory.Options myBitmapOptions; private final android.view.ViewGroup.LayoutParams params = new LayoutParams(LayoutParams.FILL_PARENT, android.view.ViewGroup.LayoutParams.FILL_PARENT); public StopMotionRelativeLayout(Context context, AttributeSet attrs) { super(context, attrs); myContext = context; this.setBackgroundColor(Color.GREEN); //init images surfaceView1 = new SurfaceView(myContext,attrs); surfaceView1.setVisibility(View.INVISIBLE); this.addView(surfaceView1, params); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); myBitmapOptions = new Options(); myBitmapOptions.outWidth = widthMeasureSpec; myBitmapOptions.outHeight = heightMeasureSpec; surfaceView1.setBackgroundDrawable(new BitmapDrawable(BitmapFactory.decodeResource(this.myContext.getResources(), R.drawable.golf1, myBitmapOptions))); } } I get the following error: NotFoundException: Could not find drawable resource matching value 0x7F020002 (resolved name: golf1) in current configuration. I have seen this type of error may times now and it always happens when I try to load something from a resource file via code and not XML. Curiously, this error does not stop me from compiling the app, and the app runs without error in the emulator. I'd like to get back the use of my layout editor though... Please help. UPDATE: Here is the layout XML <?xml version="1.0" encoding="utf-8"?> <com.games.test.StopMotionRelativeLayout android:id="@+id/RelativeLayout01" android:layout_width="fill_parent" android:layout_height="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android"> </com.games.test.StopMotionRelativeLayout>

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• Removing PDF attachments via itext

  - by r00fus

  I'm trying to remove attachments from a number of my pdf files (I can extract via pdftk, so preserving them is not an issue). I coded the following based on an example found from a google search: import java.io.FileOutputStream; import java.io.IOException; import com.lowagie.text.*; import com.lowagie.text.pdf.*; class pdfremoveattachment { public static void main(String[] args) throws IOException, DocumentException { if (args.length < 2) { System.out.println("Usage: java PDFremoveAttachments source.pdf target.pdf"); System.exit(1); } PdfReader sourcePDF = new PdfReader(args[0]); removeAttachments(sourcePDF); FileOutputStream targetFOS = new FileOutputStream(args[1]); PdfStamper targetPDF = new PdfStamper(sourcePDF,targetFOS); targetPDF.close(); } public static void removeAttachments(PdfReader reader) { PdfDictionary catalog = reader.getCatalog(); // System.out.println(catalog.getAsDict(PdfName.NAME)); // this would print "null" PdfDictionary names = (PdfDictionary)PdfReader.getPdfObject(catalog.get(PdfName.NAMES)); // System.out.println(names.toString()); //this returns NPE if( names != null) { PdfDictionary files = (PdfDictionary) PdfReader.getPdfObject(names.get(PdfName.FILEATTACHMENT)); if( files!= null ){ for( Object key : files.getKeys() ){ files.remove((PdfName)key); } files = (PdfDictionary) PdfReader.getPdfObject(names.get(PdfName.EMBEDDEDFILES)); } if( files!= null ){ for( Object key : files.getKeys() ){ files.remove((PdfName)key); } reader.removeUnusedObjects(); } } } } If anyone knows how I might be able to remove attachments, I'd greatly appreciate a reply.

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