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  • Load Testing Java Web Application - find TPS / Avg transaction response time

    - by Steve
    I would like to build my own load testing tool in Java with the goal of being able to load test a web application I am building throughout the development cycle. The web application will be receiving server to server HTTP Post requests and I would like to find its starting transaction per second (TPS) capacity along with the avgerage response time. The Post request and response messages will be in XML (I dont' think that's really applicable though :) ). I have written a very simple Java app to send transactions and count how many transactions it was able to send in one second (1000 ms) however I don't think this is the best way to load test. Really what I want is to send any number of transactions at exactly the same time - i.e. 10, 50, 100 etc. Any help would be appreciated! Oh and here is my current test app code: Thread[] t = new Thread[1]; for (int a = 0; a < t.length; a++) { t[a] = new Thread(new MessageLoop()); } startTime = System.currentTimeMillis(); System.out.println(startTime); for (int a = 0; a < t.length; a++) { t[a].start(); } while ((System.currentTimeMillis() - startTime) < 1000 ) { } if ((System.currentTimeMillis() - startTime) > 1000 ) { for (int a = 0; a < t.length; a++) { t[a].interrupt(); } } long endTime = System.currentTimeMillis(); System.out.println(endTime); System.out.println("Total time: " + (endTime - startTime)); System.out.println("Total transactions: " + count); private static class MessageLoop implements Runnable { public void run() { try { //Test Number of transactions while ((System.currentTimeMillis() - startTime) < 1000 ) { // SEND TRANSACTION HERE count++; } } catch (Exception e) { } } }

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  • Is it possible, in a django template, to check if an object is contained in a list

    - by AlexH
    I'm very new to django, about a week into it. I'm making a site where users enter stuff, then other users can vote on whether they like the stuff or not. I know it's not so novel, but it's a good project to learn a bunch of tools. I have a many-to-many table for storing who likes or dislikes what. Before I render the page, I pull out all the likes and dislikes for the current user, along with the stuff I'm going to show on the page. When I render the page, I go through the list of stuff I'm going to show and print them out one at a time. I want to show the user which stuff they liked, and which they didn't. So in my django template, I have an object called entry. I also have two lists of objects called likes and dislikes. Is there any way to determine if entry is a member of either list, inside my django template. I think what I'm looking for is a filter where I can say something like {% if entry|in:likes %} or {% if likes|contains:entry %} I know I could add a method to my model and check for each entry individually, but that seems like it would be database intensive. Is there a better way to think about this problem?

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  • iPhone: Low memory crash...

    - by MacTouch
    Once again I'm hunting memory leaks and other crazy mistakes in my code. :) I have a cache with frequently used files (images, data records etc. with a TTL of about one week and a size limited cache (100MB)). There are sometimes more then 15000 files in a directory. On application exit the cache writes an control file with the current cache size along with other useful information. If the applications crashes for some reason (sh.. happens sometimes) I have in such case to calculate the size of all files on application start to make sure I know the cache size. My app crashes at this point because of low memory and I have no clue why. Memory leak detector does not show any leaks at all. I do not see any too. What's wrong with the code below? Is there any other fast way to calculate the total size of all files within a directory on iPhone? Maybe without to enumerate the whole contents of the directory? The code is executed on the main thread. NSUInteger result = 0; NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; NSDirectoryEnumerator *dirEnum = [[[NSFileManager defaultManager] enumeratorAtPath:path] retain]; int i = 0; while ([dirEnum nextObject]) { NSDictionary *attributes = [dirEnum fileAttributes]; NSNumber* fileSize = [attributes objectForKey:NSFileSize]; result += [fileSize unsignedIntValue]; if (++i % 500 == 0) { // I tried lower values too [pool drain]; } } [dirEnum release]; dirEnum = nil; [pool release]; pool = nil; Thanks, MacTouch

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  • I'm graduating with a Computer Science degree but I don't feel like I know how to program.

    - by Wendy Peters
    I'm graduating with a Computer Science degree but I see websites like Stackoverflow and search engines like Google and don't know where I'd even begin to write something like that. During one summer I worked as a iPhone developer, but I felt like I was mostly gluing together libraries that other people had written with little understanding of what's happening underneath the hood. I'm trying to improve my knowledge by studying algorithms, but it is a long and painful process. I find algorithms difficult and at the rate I am working through my book it will a decade will have passed before I will finish. Given my current situation, I've spent a month looking for work but my skills (C, Python, Objective-C) are not so desirable in the local market, where C#, Java, and web development are much higher in demand. My GPA is ok (3.0) but it's not high enough to apply to the large companies or return for graduate studies and I don't have a good network of friends. Basically I'm graduating with a Computer Science degree but I don't feel like I know how to program. I thought that joining a company and programming full-time would give me a chance to develop my skills and learn from those more experienced than myself, but I'm struggling to find work and am starting to get really frustrated. I am going to cast my net wider and look beyond the city I've grown up in, but what have other people in similar situation tried to do?

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  • Is it possible to De-Serialize a new Derived class using Old Binary?

    - by Anand
    In my project I have a class which I Serialize in Binary format to the disk. Due to some new requirement I need to create a new class which is derived from the original class. eg [Serializable] public class Sample { String someString; int someInt; public Sample() { } public Sample(String _someString, int _someInt) { this.someInt = _someInt; this.someString = _someString; } public String SomeString { get { return someString; } } public int SomeInt { get { return someInt; } } } [Serializable] public class DerivedSample : Sample { String someMoreString; int someMoreInt; public DerivedSample () : base() { } public DerivedSample (String _someString, int _someInt, String _someMoreString, int _someMoreInt) : base(_someString, _someInt) { this.someMoreString = _someMoreString; this.someMoreInt = _someMoreInt; } public String SomeMoreString { get { return someMoreString; } } public int SomeMoreInt { get { return someMoreInt; } } } When I try to De serialize an old file which contains only object of Sample it works fine, in the current assembly. That means backward compatibility is there. But when I try to deserialize the file which contains object of DerivedSample using the previous version of the assembly application crashes. Which means forward compatibilty needs to be taken care off... It it possible to say read only the base class part of the object from new version of the file?

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  • How to find nearest week day for an arbitrary date?

    - by Stig Brautaset
    Is there a more elegant way than the below to find the nearest day of the week for a given date using JodaTime? I initially thought setCopy() would be it, but this sets the day to the particular day in the same week. Thus, if ld is 2011-11-27 and day is "Monday" the following function returns 2011-11-21, and not 2011-11-28 as I want. // Note that "day" can be _any_ day of the week, not just weekdays. LocalDate getNearestDayOfWeek(LocalDate ld, String day) { return ld.dayOfWeek().setCopy(day); } Below is a work-around I came up with that works for the particular constraints in my current situation, but I'd love to get help find a completely generic solution that works always. LocalDate getNearestDayOfWeek(LocalDate ld, String day) { LocalDate target = ld.dayOfWeek().setCopy(day); if (ld.getDayOfWeek() > DateTimeConstants.SATURDAY) { target = target.plusWeeks(1); } return target; } Looking more into this I came up with this, which seems to be a more correct solution, though it seems awfully complicated: LocalDate getNearestDayOfWeek(LocalDate ld, String day) { LocalDate target = ld.dayOfWeek().setCopy(day); if (target.isBefore(ld)) { LocalDate nextTarget = target.plusWeeks(1); Duration sincePrevious = new Duration(target.toDateMidnight(), ld.toDateMidnight()); Duration untilNext = new Duration(ld.toDateMidnight(), nextTarget.toDateMidnight()); if (sincePrevious.isLongerThan(untilNext)) { target = nextTarget; } } return target; }

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  • TinyMCE loading lang/plugins/theme from incorrect directory

    - by Anonymous
    I am having trouble with TinyMCE. When it is searching for the lang, theme, and plugins, it is supposed to look in the directory where the base script files are located. however, instead of doing that, it is using the current loaded page as the root for searching. I am looking at the "loadScripts" function in the src file, but changing the path doesn't seem to provide any meaningful effect. Here is the unmodified loadScripts function for your review: // Load scripts function loadScripts() { if (s.language) sl.add(tinymce.baseURL + '/langs/' + s.language + '.js'); if (s.theme && s.theme.charAt(0) != '-' && !ThemeManager.urls[s.theme]) ThemeManager.load(s.theme, 'themes/' + s.theme + '/editor_template' + tinymce.suffix + '.js'); each(explode(s.plugins), function(p) { if (p && p.charAt(0) != '-' && !PluginManager.urls[p]) { // Skip safari plugin for other browsers if (!isWebKit && p == 'safari') return; PluginManager.load(p, 'plugins/' + p + '/editor_plugin' + tinymce.suffix + '.js'); } }); // Init when que is loaded sl.loadQueue(function() { if (!t.removed) t.init(); }); }; loadScripts(); }

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  • Does .Net use Device Dependent or Device Independent Bitmaps?

    - by Brian
    When loading an image into memory, does .Net use DDB, DIB, or something else entirely? If possible, please cite your sources. I'm wondering because we currently have a classic ASP application that is using a 3rd party component to load images that is occasionally creating a “Not enough storage is available to process this command.” error. The error is very inconsistent but tends to happen on larger images (not always, but often). After resetting IIS, processing the same file again typically works just fine. After much research I have found that DDBs tend to have this problem when processing large images because they work out of video memory. Considering that we are running on a web server with an integrated video card and limited shared memory, this could certainly be our problem. We are in the early stages of converting our app to .Net and am wondering if using .Net for this might be a viable alternative to our current method which is why I am asking the question. Any advice is welcome :) but out of curiosity if nothing else, I am really hoping for an answer to the question; does .Net use DDB or DIB?

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  • Optimizing this "Boundarize" method for Numerics in Ruby

    - by mstksg
    I'm extending Numerics with a method I call "Boundarize" for lack of better name; I'm sure there are actually real names for this. But its basic purpose is to reset a given point to be within a boundary. That is, "wrapping" a point around the boundary; if the area is betweeon 0 and 100, if the point goes to -1, -1.boundarize(0,100) = 99 (going one too far to the negative "wraps" the point around to one from the max). 102.boundarize(0,100) = 2 It's a very simple function to implement; when the number is below the minimum, simply add (max-min) until it's in the boundary. If the number is above the maximum, simply subtract (max-min) until it's in the boundary. One thing I also need to account for is that, there are cases where I don't want to include the minimum in the range, and cases where I don't want to include the maximum in the range. This is specified as an argument. However, I fear that my current implementation is horribly, terribly, grossly inefficient. And because every time something moves on the screen, it has to re-run this, this is one of the bottlenecks of my application. Anyone have any ideas? module Boundarizer def boundarize min=0,max=1,allow_min=true,allow_max=false raise "Improper boundaries #{min}/#{max}" if min >= max new_num = self if allow_min while new_num < min new_num += (max-min) end else while new_num <= min new_num += (max-min) end end if allow_max while new_num > max new_num -= (max-min) end else while new_num >= max new_num -= (max-min) end end return new_num end end class Numeric include Boundarizer end

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  • Creating sublines on Joomla menu items

    - by ploughansen
    In my toplevel menu items, I would like to make a subline for each item. I don't think it's possible to do by default, byt YooTheme has done it in many of their templates. The menu output look like this <div class="moduletable_menu"> <ul id="mainmenu" class="menu"> <li class="active item1" id="current"> <a href="URL_HIDDEN"> <span>Services</span> </a> </li> </ul> This basically outputs a one line menu item like so: Services What I would like to do is have a menu item like this: Services Service x, Service y, Service z For reference, have a look at the main menu on the YooTheme demo page. The way YooTheme does this, is using two pipes (||) as a linebreak, so in the Joomla backend you type "Services||Service x, Service y, Service z" as the menu title, and then there must be some fancy javascript that breaks this title into two spans, ready to be styled using css. Does anyone know of an easy way to code this? Please note that I am looking to build this feature into a custom template (ie. non-yootheme). Also note that I am not using MooTools, but Jquery instead.

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  • Better code for accessing fields in a matlab structure array?

    - by John
    I have a matlab structure array Modles1 of size (1x180) that has fields a, b, c, ..., z. I want to understand how many distinct values there are in each of the fields. i.e. max(grp2idx([foo(:).a])) The above works if the field a is a double. {foo(:).a} needs to be used in the case where the field a is a string/char. Here's my current code for doing this. I hate having to use the eval, and what is essentially a switch statement. Is there a better way? names = fieldnames(Models1); for ix = 1 : numel(names) className = eval(['class(Models1(1).',names{ix},')']); if strcmp('double', className) || strcmp('logical',className) eval([' values = [Models1(:).',names{ix},'];']); elseif strcmp('char', className) eval([' values = {Models1(:).',names{ix},'};']); else disp(['Unrecognized class: ', className]); end % this line requires the statistics toolbox. [g, gn, gl] = grp2idx(values); fprintf('%30s : %4d\n',names{ix},max(g)); end

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  • XP Leveling System - PHP

    - by Michael Rich
    Rank Table ID, Primary Key RANK, The rank or level, 1 being the highest and 3 the lowest MIN_SCORE, The minimum amount of point or XP needed to reach the rank NAME, The associated name of the rank Rank Table +----+------+-----------+-------------------------+ | ID | RANK | MIN_SCORE | NAME | +----+------+-----------+-------------------------+ | 1 | 1 | 18932 | Editor-in-Chief | | 2 | 2 | 15146 | Senior Technical Writer | | 3 | 3 | 12116 | Senior Copywriter | +----+------+-----------+-------------------------+ Ranking Table ID, Primary Key FK_MEMEBER_ID, Foreign Key to member's Primary Key FK_RANK, Foreign Key to Author Rank Table's Rank column (top) SCORE, The member's current earned score or XP Ranking Table +-----+--------------+---------+-------+ | ID | FK_MEMBER_ID | FK_RANK | SCORE | +-----+--------------+---------+-------+ | 1 | 1 | 1 | 17722 | | 2 | 2 | 2 | 16257 | | 3 | 3 | 3 | 12234 | +-----+--------------+---------+-------+ In my class I have stored the ranks -- matching those in the Rank Table -- and correlating minimum scores; RANK as key and MINIMUM_SCORE as value. When a member's score (XP) is updated (up/down) I want to test that updated score against the below array to determine if their rank needs updating too. private $scores = array('3' => '12116', '2' => '15146', '1' => '18932',); Using the updated score, how could I determine the correlating rank from the above array? Everything is open to scrutiny, this is my first time creating a ranking system so I hope to get it right :)

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  • SharePoint Web Part on Masterpage not displaying on SubSite

    - by madatanic
    Hi all, Scenario: - A out-of-the-box DataFormWebPart on masterpage connected to a top-level site List. - A subsite using that same masterpage from top-level site. - Error happens when accessing the sub site as below Stack Trace [InvalidOperationException: Operation is not valid due to the current state of the object.] Microsoft.SharePoint.SPFolder.get_ContentTypeOrder() +488 Microsoft.SharePoint.SPContext.get_ContentTypes() +898 Microsoft.SharePoint.SPContext.get_ContentType() +472 Microsoft.SharePoint.SPContext.get_Fields() +271 Microsoft.SharePoint.WebControls.FormComponent.get_Fields() +44 Microsoft.SharePoint.WebControls.FieldMetadata.get_Field() +419 Microsoft.SharePoint.WebControls.FormField.CreateChildControls() +596 System.Web.UI.Control.EnsureChildControls() +87 Microsoft.SharePoint.WebControls.BaseFieldControl.OnLoad(EventArgs e) +176 System.Web.UI.Control.LoadRecursive() +50 System.Web.UI.Control.LoadRecursive() +141 System.Web.UI.Control.AddedControl(Control control, Int32 index) +265 System.Web.UI.ControlCollection.Add(Control child) +80 System.Web.UI.Control.AddParsedSubObject(Object obj) +41 Microsoft.SharePoint.WebPartPages.WebPart.AddParsedSubObject(Object obj) +1149 Microsoft.SharePoint.WebPartPages.DataFormWebPart.CreateChildControls() +1267 System.Web.UI.Control.EnsureChildControls() +87 System.Web.UI.Control.PreRenderRecursiveInternal() +44 System.Web.UI.WebControls.WebParts.WebPart.PreRenderRecursiveInternal() +42 System.Web.UI.Control.PreRenderRecursiveInternal() +171 System.Web.UI.Control.PreRenderRecursiveInternal() +171 System.Web.UI.Control.PreRenderRecursiveInternal() +171 System.Web.UI.Control.PreRenderRecursiveInternal() +171 System.Web.UI.Control.PreRenderRecursiveInternal() +171 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +842 I have tried the solution from this site to enable the subsite to access top level site list. Is this a bug? Any help would be appreciated.

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  • Algorithm for generating an array of non-equal costs for a transport problem optimization

    - by Carlos
    I have an optimizer that solves a transportation problem, using a cost matrix of all the possible paths. The optimiser works fine, but if two of the costs are equal, the solution contains one more path that the minimum number of paths. (Think of it as load balancing routers; if two routes are same cost, you'll use them both.) I would like the minimum number of routes, and to do that I need a cost matrix that doesn't have two costs that are equal within a certain tolerance. At the moment, I'm passing the cost matrix through a baking function which tests every entry for equality to each of the other entries, and moves it a fixed percentage if it matches. However, this approach seems to require N^2 comparisons, and if the starting values are all the same, the last cost will be r^N bigger. (r is the arbitrary fixed percentage). Also there is the problem that by multiplying by the percentage, you end up on top of another value. So the problem seems to have an element of recursion, or at least repeated checking, which bloats the code. The current implementation is basically not very good (I won't paste my GOTO-using code here for you all to mock), and I'd like to improve it. Is there a name for what I'm after, and is there a standard implementation? Example: {1,1,2,3,4,5} (tol = 0.05) becomes {1,1.05,2,3,4,5}

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  • How to make a program not show up in Alt-Tab or on the taskbar.

    - by Scott Chamberlain
    I have a program that needs to sit in the background and when a user connects to a RDP session it will do some stuff then launch a program. when the program is closed it will do some housekeeping and logoff the session. The current way I am doing it is like this I have the terminal server launch this application. I have it set as a windows forms application and my code is this public static void Main() { //Do some setup work Process proc = new Process(); //setup the process proc.Start(); proc.WaitForExit(); //Do some housecleaning NativeMethods.ExitWindowsEx(0, 0); } I really like this because there is no item in the taskbar and there is nothing showing up in alt-tab. However to do this I gave up access to functions like void WndProc(ref Message m) So Now I can't listen to windows messages (Like WTS_REMOTE_DISCONNECT or WTS_SESSION_LOGOFF) and do not have a handle to use for for bool WTSRegisterSessionNotification(IntPtr hWnd, int dwFlags); I would like my code to be more robust so it will do the housecleaning if the user logs off or disconnects from the session before he closes the program. Any reccomendations on how I can have my cake and eat it too?

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  • In Perl, how can I wait for threads to end in parallel?

    - by Pmarcoen
    I have a Perl script that launches 2 threads,one for each processor. I need it to wait for a thread to end, if one thread ends a new one is spawned. It seems that the join method blocks the rest of the program, therefore the second thread can't end until everything the first thread does is done which sort of defeats its purpose. I tried the is_joinable method but that doesn't seem to do it either. Here is some of my code : use threads; use threads::shared; @file_list = @ARGV; #Our file list $nofiles = $#file_list + 1; #Real number of files $currfile = 1; #Current number of file to process my %MSG : shared; #shared hash $thr0 = threads->new(\&process, shift(@file_list)); $currfile++; $thr1 = threads->new(\&process, shift(@file_list)); $currfile++; while(1){ if ($thr0->is_joinable()) { $thr0->join; #check if there are files left to process if($currfile <= $nofiles){ $thr0 = threads->new(\&process, shift(@file_list)); $currfile++; } } if ($thr1->is_joinable()) { $thr1->join; #check if there are files left to process if($currfile <= $nofiles){ $thr1 = threads->new(\&process, shift(@file_list)); $currfile++; } } } sub process{ print "Opening $currfile of $nofiles\n"; #do some stuff if(some condition){ lock(%MSG); #write stuff to hash } print "Closing $currfile of $nofiles\n"; } The output of this is : Opening 1 of 4 Opening 2 of 4 Closing 1 of 4 Opening 3 of 4 Closing 3 of 4 Opening 4 of 4 Closing 2 of 4 Closing 4 of 4

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  • Making two Windows using CreateWindowsEx()

    - by Jamie Keeling
    Hello, I have a windows form that has a simple menu and performs a simple operation, I want to be able to create another windows form with all the functionality of a menu bar, message pump etc.. as a separate thread so I can then share the results of the operation to the second window. I.E. 1) Form A opens Form B opens as a separate thread 2)Form A performs operation 3)Form A passes results via memory to Form B 4)Form B display results I'm confused as to how to go about it, the main app runs fine but i'm not sure how to add a second window if the first one already exists. I think that using CreateWindow will allow me to make another window but again i'm not sure how to access the message pump so I can respond to certain events like WM_CREATE on the second window. I hope it makes sense. Thanks! Edit: I've attempted to make a second window and although this does compile, no windows show atall on build. ////////////////////// // WINDOWS FUNCTION // ////////////////////// LRESULT CALLBACK WindowFunc(HWND hMainWindow, UINT message, WPARAM wParam, LPARAM lParam) { //Fields WCHAR buffer[256]; struct DiceData storage; HWND hwnd; // Act on current message switch(message) { case WM_CREATE: AddMenus(hMainWindow); hwnd = CreateWindowEx( 0, "ChildWClass", (LPCTSTR) NULL, WS_CHILD | WS_BORDER | WS_VISIBLE, 0, 0, 0, 0, hMainWindow, NULL, NULL, NULL); ShowWindow(hwnd, SW_SHOW); break; Any suggestions as to why this happens?

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  • Parsing: How to make error recovery in grammars like " a* b*"?

    - by Lavir the Whiolet
    Let we have a grammar like this: Program ::= a* b* where "*" is considered to be greedy. I usually implement "*" operator naively: Try to apply the expression under "*" to input one more time. If it has been applied successfully then we are still under current "*"-expression; try to apply the expression under "*" one more time. Otherwise we have reached next grammar expression; put characters parsed by expression under "*" back into input and proceed with next expression. But if there are errors in input in any of "a*" or "b*" part such a parser will "think" that in position of error both "a*" and "b*" have finished ("let's try "a"... Fail! OK, it looks like we have to proceed to "b*". Let's try "b"... Fail! OK, it looks like the string should have been finished...). For example, for string "daaaabbbbbbc" it will "say": "The string must end at position 1, delete superflous characters: daaaabbbbbbc". In short, greedy "*" operator becomes lazy if there are errors in input. How to make "*" operator to recover from errors nicely?

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  • Core Data object into an NSDictionary with possible nil objects

    - by Chuck
    I have a core data object that has a bunch of optional values. I'm pushing a table view controller and passing it a reference to the object so I can display its contents in a table view. Because I want the table view displayed a specific way, I am storing the values from the core data object into an array of dictionaries then using the array to populate the table view. This works great, and I got editing and saving working properly. (i'm not using a fetched results controller because I don't have anything to sort on) The issue with my current code is that if one of the items in the object is missing, then I end up trying to put nil into the dictionary, which won't work. I'm looking for a clean way to handle this, I could do the following, but I can't help but feeling like there's a better way. *passedEntry is the core data object handed to the view controller when it is pushed, lets say it contains firstName, lastName, and age, all optional. if ([passedEntry firstName] != nil) { [dictionary setObject:[passedEntry firstName] forKey:@"firstName"] } else { [dictionary setObject:@"" forKey:@"firstName"] } And so on. This works, but it feels kludgy, especially if I end up adding more items to the core data object down the road.

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  • Appropriate uses of Monad `fail` vs. MonadPlus `mzero`

    - by jberryman
    This is a question that has come up several times for me in the design code, especially libraries. There seems to be some interest in it so I thought it might make a good community wiki. The fail method in Monad is considered by some to be a wart; a somewhat arbitrary addition to the class that does not come from the original category theory. But of course in the current state of things, many Monad types have logical and useful fail instances. The MonadPlus class is a sub-class of Monad that provides an mzero method which logically encapsulates the idea of failure in a monad. So a library designer who wants to write some monadic code that does some sort of failure handling can choose to make his code use the fail method in Monad or restrict his code to the MonadPlus class, just so that he can feel good about using mzero, even though he doesn't care about the monoidal combining mplus operation at all. Some discussions on this subject are in this wiki page about proposals to reform the MonadPlus class. So I guess I have one specific question: What monad instances, if any, have a natural fail method, but cannot be instances of MonadPlus because they have no logical implementation for mplus? But I'm mostly interested in a discussion about this subject. Thanks! EDIT: One final thought occured to me. I recently learned (even though it's right there in the docs for fail) that monadic "do" notation is desugared in such a way that pattern match failures, as in (x:xs) <- return [] call the monad's fail. It seems like the language designers must have been strongly influenced by the prospect of some automatic failure handling built in to haskell's syntax in their inclusion of fail in Monad.

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  • Select rows from table1 and all the children from table2 into an object

    - by Patrick
    I want to pull data from table "Province_Notifiers" and also fetch all corresponding items from table "Province_Notifier_Datas". The table "Province_Notifier" has a guid to identify it (PK), table "Province_Notifier_Datas" has a column called BelongsToProvinceID witch is a foreign key to the "Province_Notifier" tables guid. I tried something like this: var records = from data in ctx.Province_Notifiers where DateTime.Now >= data.SendTime && data.Sent == false join data2 in ctx.Province_Notifier_Datas on data.Province_ID equals data2.BelongsToProvince_ID select new Province_Notifier { Email = data.Email, Province_ID = data.Province_ID, ProvinceName = data.ProvinceName, Sent = data.Sent, UserName = data.UserName, User_ID = data.User_ID, Province_Notifier_Datas = (new List<Province_Notifier_Data>().AddRange(data2)) }; This line is not working and i am trying to figure out how topull the data from table2 into that Province_Notifier_Datas variable. Province_Notifier_Datas = (new List<Province_Notifier_Data>().AddRange(data2)) I can add a record easily by adding the second table row into the Province_Notifier_Datas but i can't fetch it back. Province_Notifier dbNotifier = new Province_Notifier(); // set some values for dbNotifier dbNotifier.Province_Notifier_Datas.Add( new Province_Notifier_Data { BelongsToProvince_ID = userInput.Value.ProvinceId, EventText = GenerateNotificationDetail(notifierDetail) }); This works and inserts the data correctly into both tables. Edit: These error messages is thrown: Cannot convert from 'Province_Notifier_Data' to 'System.Collections.Generic.IEnumerable' If i look in Visual Studio, the variable "Province_Notifier_Datas" is of type System.Data.Linq.EntitySet The best overloaded method match for 'System.Collections.Generic.List.AddRange(System.Collections.Generic.IEnumerable)' has some invalid arguments Edit: var records = from data in ctx.Province_Notifiers where DateTime.Now >= data.SendTime && data.Sent == false join data2 in ctx.Province_Notifier_Datas on data.Province_ID equals data2.BelongsToProvince_ID into data2list select new Province_Notifier { Email = data.Email, Province_ID = data.Province_ID, ProvinceName = data.ProvinceName, Sent = data.Sent, UserName = data.UserName, User_ID = data.User_ID, Province_Notifier_Datas = new EntitySet<Province_Notifier_Data>().AddRange(data2List) }; Error 3 The name 'data2List' does not exist in the current context.

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  • File.Replace throwing IOException

    - by WebDevHobo
    I have an app that can make modify images. In some cases, this makes the filesize smaller, in some cases bigger. The program doesn't have an option to "not replace the file if result has a bigger filesize". So I wrote a little C# app to try and solve this. Instead of overwriting the files, I make the app write the result to a folder under the current one and name that folder Test. The C# app I wrote compares grabs the contents of both folders and puts the full path to the file(s) in two List objects. I then compare and replace. The replacing isn't working however. I get the following IOException: Unable to remove the file to be replaced The location is on an external hard-drive, on which I have full rights. Now, I know I can just do File.Delete and File.Move in that order, but this exception has gotten me interested in why this particular setup wont work. Here's the source code: http://pastebin.com/4Vq82Umu And yes, the file specified as last argument of the Replace function does exist.

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  • Mouse management in JavaScript games

    - by Jakob
    Im using JavaScript, the HTML5 canvas-element and WebGL to make a simple 3D-game in first person view for fun. Ideally, I would like to control my movement by using the keyboard to move and the mouse to look around, like you usually do in FPS-games. As you probably understand, there are some limits to this in the browser, since the mouse cant be captured: When using the onmousemove event, no further movement will be detected when the mouse pointer reaches the border of my screen (which means that I wont be able to run in a circle for example) Seeing the mouse move across the screen is not the end of the world, but it is a little annoying From what I know, it's impossible to hide the mouse as well as setting it's position in JavaScript. Hence, my question is this: If we cant to those things, what can we do in order to get close to the desktop gaming experience when it comes to the mouse in the browser? And I mean right now, using current APIs. Not "what could be changed in some standard to make life easier". Also, I realize that I could use the keyboard to look around, but then we're back in 1995 when Quake were actually played like that. And of course I know that it would be easier to write a desktop application or use Flash at least, but Im trying to push JavaScript's limits here. Apart from those things, what are your suggestions? Any kind of reference, existing game, crazy idea, hack or even browser specific solution would be appreciated.

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  • php cURL. preg_match , extract text from xhtml

    - by Michael
    I'm trying to extract the price from the bellow html page/link using php cURL and preg_match . Basically I'm expecting for this code to output 4,550 but for some reasons I get Notice: Undefined offset: 1 in C:\wamp\www\test.php on line 22 I think that the pattern is correct because if I put the html itself in a variable and escape the "" it works ! . Also if I output (echo $result;) it displays the html properly grabbed from foxtons website so I just can't figure it out why the whole thing doesn't work . I need to make this work and also I would appreciate if you would tell me why is that notice generated and why my current script doesn't work. $url = "http://www.foxtons.co.uk/search?bedrooms_from=0&property_id=727717"; $ch = curl_init($url); curl_setopt($ch, CURLOPT_HEADER, 0); curl_setopt($ch,CURLOPT_RETURNTRANSFER, 1); $result = curl_exec($ch); curl_exec($ch); curl_close($ch); $result2 = str_replace('"', '\"', $result); $tagname1= ");<\/script "; $tagname2= "<\/noscript per month<\/a"; $pattern = "/$tagname1(.*?)$tagname2/"; preg_match($pattern, $result, $matches); $prices = $matches[1]; print_r($prices); ?

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  • WPF tree data binding model & repository

    - by Am
    Hi, I have a well defined tree repository. Where I can rename items, move them up, down, etc. Add new and delete. The data is stored in a table as follows: Index Parent Label Left Right 1 0 root 1 14 2 1 food 2 7 3 2 cake 3 4 4 2 pie 5 6 5 1 flowers 8 13 6 5 roses 9 10 7 5 violets 11 12 Representing the following tree: (1) root (14) (2) food (7) (8) flowers (13) (3) cake (4) (5) pie (6) (9) roeses (10) (11) violets (12) or root food cake pie flowers roses violets Now, my problem is how to represent this in a bindable way, so that a TreeView can handle all the possible data changes? Renaming is easy, all I need is to make the label an updatble field. But what if a user moves flowers above food? I can make the relevant data changes, but they cause a complete data change to all other items in the tree. And all the examples I found of bindable hierarchies are good for non static trees.. So my current (and bad) solution is to reload the displayed tree after relocation change. Any direction will be good. Thanks

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