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  • Class<T> and static method Class.forName() drive me crazy.

    - by matt
    Hi, this code doesn't compile. I'm wondering what I am doing wrong: private static Importable getRightInstance(String s) throws Exception { Class<Importable> c = Class.forName(s); Importable i = c.newInstance(); return i; } where Importable is an interface and the string s is the name of an implementing class. The compiler says: ./Importer.java:33: incompatible types found : java.lang.Class<capture#964 of ?> required: java.lang.Class<Importable> Class<Importable> c = Class.forName(format(s)); thanks for any help! All the solutions Class<? extends Importable> c = Class.forName(s).asSubclass(Importable.class); and Class<? extends Importable> c = (Class<? extends Importable>) Class.forName(s); and Class<?> c = Class.forName(format(s)); Importable i = (Importable)c.newInstance(); give this error: Exception in thread "main" java.lang.IncompatibleClassChangeError: class C1 has interface Importable as super class where C1 is effectively a class implementing Importable, one of those i want to cast to Importable.

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  • Will WCF allow me to use object references across boundries on objects that implement INotifyPropert

    - by zimmer62
    So I've created a series of objects that interact with a piece of hardware over a serial port. There is a thread running monitoring the serial port, and if the state of the hardware changes it updates properties in my objects. I'm using observable collections, and INotifyPropertyChanged. I've built a UI in WPF and it works great, showing me real time updating when the hardware changes and allows me to send changes to the hardware as well by changing these properties using bindings. What I'm hoping is that I can run the UI on a different machine than what the hardware is hooked up to without a lot of wiring up of events. Possibly even allow multiple UI's to connect to the same service and interact with this hardware. So far I understand I'm going to need to create a WCF service. I'm trying to figure out if I'll be able to pass a reference to an object created at the service to the client leaving events intact. So that the UI will really just be bound to a remote object. Am I moving the right direction with WCF? Also I see tons of examples for WCF in C#, are there any good practical use examples in VB that might be along the lines of what I'm trying to do?

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  • What's the *right* way to handle a POST in FP?

    - by Malvolio
    I'm just getting started with FP and I'm using Scala, which may not be the best way, since I can always fall back to an imperative style if the going gets tough. I'd just rather not. I've got a very specific question that points to a broader lacuna in my understanding of FP. When a web application is processing a GET request, the user wants information that already exists on the web-site. The application only has to process and format the data in some way. The FB way is clear. When a web application is processing a POST request, the user wants change the information held on the site. True, the information is not typically held in application variables, it's in a database or a flat-file, but still, I get the feeling I'm not grokking FP properly. Is there a pattern for handling updates to static data in an FP language? My vague picture of this is that the application is handed the request and the then-current site state. The application does its thing and returns the new site-state. If the current site-state hasn't changed since the application started, the new state becomes the current state and the reply is sent back to the browser (this is my dim image of Clojure's style); if the current state has been changed (by another thread, well, something else happens ...

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  • jQuery, selecting form elements by name, getting: Error: uncaught exception: Syntax error, unrecogni

    - by Mark Steudel
    I'm trying to select an select element by name I found this thread showing how to do it, and I followed it but I'm getting Syntax error. I'm using jquery 1.4.1, here's my code. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/> <title>TODO supply a title</title> <script type="text/javascript" src="/js/jquery-1.4.1.min.js"></script> <script type="text/javascript"> $(document).ready(function(){ alert( $('select[@name="country[0]"]').val() ); }) </script> </head> <body> <form> <select name="country[0]"> <option value="23">test</option> </select> </form> </body> </html> Thanks in advance for any insight. MS

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  • Two references to the same domain/entity model

    - by Sbossb
    Problem I want to save the attributes of a model that have changed when a user edits them. Here's what I want to do ... Retrieve edited view model Get domain model and map back updated value Call the update method on repository Get the "old" domain model and compare values of the fields Store the changed values (in JSON) into a table However I am having trouble with step number 4. It seems that the Entity Framework doesn't want to hit the database again to get the model with the old values. It just returns the same entity I have. Attempted Solutions I have tried using the Find() and the SingleOrDefault() methods, but they just return the model I currently have. Example Code private string ArchiveChanges(T updatedEntity) { //Here is the problem! //oldEntity is the same as updatedEntity T oldEntity = DbSet.SingleOrDefault(x => x.ID == updatedEntity.ID); Dictionary<string, object> changed = new Dictionary<string, object>(); foreach (var propertyInfo in typeof(T).GetProperties()) { var property = typeof(T).GetProperty(propertyInfo.Name); //Get the old value and the new value from the models var newValue = property.GetValue(updatedEntity, null); var oldValue = property.GetValue(oldEntity, null); //Check to see if the values are equal if (!object.Equals(newValue, oldValue)) { //Values have changed ... log it changed.Add(propertyInfo.Name, newValue); } } var ser = new System.Web.Script.Serialization.JavaScriptSerializer(); return ser.Serialize(changed); } public override void Update(T entityToUpdate) { //Do something with this string json = ArchiveChanges(entityToUpdate); entityToUpdate.AuditInfo.Updated = DateTime.Now; entityToUpdate.AuditInfo.UpdatedBy = Thread.CurrentPrincipal.Identity.Name; base.Update(entityToUpdate); }

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  • MediaWiki: how to hide users from the user list?

    - by Dave Everitt
    I've set up Mediawiki 1.15.1 for a client who has added two users by mistake. They now want to hide these users from the user list. It seems this is done via the $wgGroupPermissions array with $wgGroupPermissions['suppress']['hideuser'] = true;, but it isn't at all clear what entry this needs for the hiding to work, or whether a new group ('hidden' or whatever) has to be created first with $wgAddGroups['bureaucrat'] = true;. For now, I've added the two users to be hidden to the 'Oversight' group which explains 'Block a username, hiding it from the public (hideuser)', but they still appear on the Special:ListUsers page. At a loss as to how the MediWiki arrays alter options displayed in the interface, so far I've added this to LocalSettings.php: $wgGroupPermissions['suppress']['hideuser'] = true; $wgAddGroups['supress'] = true; Or - since they haven't actually added anything to the wiki - could they simply be removed from the MySQL users table - although MediaWiki warns against this? Has anyone else done this successfully? Update - this is a hole in MediaWiki admin (although there are workarounds). See this thread on MediaWIki Users and the note to the reply below.

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  • ZF2 - ServiceManager injecting into 84 tables... tedious

    - by Dominic Watson
    I originally made another thread about this a couple of months ago in regards to ZF2 injecting into tables with DI during Beta 1 and figured back then that it wasn't really possible. Now ZF2 has been released as version 2.0.0 and ServiceManager is defaulted to instead of DI I guess I have the same question now I'm refactoring. I've got 84 tables that need the DbAdapter injecting into them and I'm sure there has to be a better way as I'm replicating myself SO much. public function getServiceConfig() { return array( 'factories' => array( 'accountTable' => function ($sm) { $dbAdapter = $sm->get('Zend\Db\Adapter\Adapter'); $table = new Model\DbTable\AccountTable($dbAdapter); return $table; }, 'userTable' => function ($sm) { $dbAdapter = $sm->get('Zend\Db\Adapter\Adapter'); $table = new Model\DbTable\UserTable($dbAdapter); return $table; }, // another 82 tables of the above ) ) } With the EventsManager and ServiceManager I have no idea where I stand in getting my application's instances/resources. Thanks, Dom

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  • The shell dotfile cookbook

    - by Jason Baker
    I constantly hear from other people about how much of the stuff they've used to customize their *nix setup they've shamelessly stolen from other people. So in that spirit, I'd like to start a place to share that stuff here on SO. Here are the rules: DON'T POST YOUR ENTIRE DOTFILE. Instead, just show us the cool stuff. One recipe per answer You may, however, post multiple versions of your recipe in the same answer. For example, you may post a version that works for bash, a version that works for zsh, and a version that works for csh in the same answer. State what shells you know your recipe will work with in the answer. Let's build this cookbook as a team. If you find out that an answer works with other shells other than the one the author posted, edit it in. If you like an idea and rewrite it to work with another shell, edit the modified version in to the original post. Give credit where credit is due. If you got your idea from someone else, give them credit if possible. And for those of you (justifiably) asking "Why do we need another one of these threads?": Most of what I've seen is along the lines of "post your entire dotfile." Personally, I don't want to try to parse through a person's entire dotfile to figure out what I want. I just want to know about all the cool parts of it. It's helpful to have a single dotfile thread. I think most of the stuff that works in bash will work in zsh and it may be adapted to work with csh fairly easily.

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  • Committing to a different branch with commit -r

    - by Amarghosh
    Does CVS allow committing a file to a different branch than the one it was checked out from? The man page and some sites suggest that we can do a cvs ci -r branch-1 file.c but it gives the following error: cvs commit: Up-to-date check failed for `file.c' cvs [commit aborted]: correct above errors first! I did a cvs diff -r branch-1 file.c to make sure that contents of file.c in my BASE and branch-1 are indeed the same. I know that we can manually check out using cvs co -r branch-1, merge the main branch to it (and fix any merge issues) and then do a check in. The problem is that there are a number of branches and I would like to automate things using a script. This thread seems to suggest that -r has been removed. Can someone confirm that? If ci -r is not supported, I am thinking of doing something like: Make sure the branch versions and base version are the same with a cvs diff Check in to the current branch Keep a copy of the file in a temp file For each branch: Check out from branch with -r replace the file with the temp file Check in (it'll go the branch as -r is sticky) Delete the temp file The replacing part sounds like cheating to me - can you think of any potential issues that might occur? Anything I should be careful about? Is there any other way to automate this process?

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  • How can I run some common code from both (a) scheduled via Windows Task & (b) manually from within W

    - by Greg
    Hi, QUESTION - How can I run some common code from both (a) scheduled via Windows Task & (b) manually from within WinForms app? BACKGROUND: This follows on from the http://stackoverflow.com/questions/2489999/how-can-i-schedule-tasks-in-a-winforms-app thread REQUIREMENTS C# .NETv3.5 project using VS2008 There is an existing function which I want to run both (a) manually from within the WinForms application, and (b) scheduled via Windows Task. APPROACHES So what I'm trying to understand is what options are there to make this work eg Is it possible for a windows task to trigger a function to run within a running/existing WinForms application? (doesn't sound solid I guess) Split code out into two projects and duplicate for both console application that the task manager would run AND code that the winforms app would run Create a common library and re-use this for both the above-mentioned projects in the bullet above Create a service with an interface that both the task manager can access plus the winforms app can manage Actually each of these approaches sounds quite messy/complex - would be really nice to drop back to have the code only once within the one project in VS2008, the only reason I ask about this is I need to have a scheduling function and the suggestion has been to use http://taskscheduler.codeplex.com/ as the means to do this, which takes the scheduling out of my VS2008 project... thanks

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  • Java: Using GSon incorrectly? (null pointer exception)

    - by Rosarch
    I'm trying to get the hits of a google search from a string of the query. public class Utils { public static int googleHits(String query) throws IOException { String googleAjax = "http://ajax.googleapis.com/ajax/services/search/web?v=1.0&q="; String json = stringOfUrl(googleAjax + query); JsonObject hits = new Gson().fromJson(json, JsonObject.class); return hits.get("estimatedResultCount").getAsInt(); } public static String stringOfUrl(String addr) throws IOException { ByteArrayOutputStream output = new ByteArrayOutputStream(); URL url = new URL(addr); IOUtils.copy(url.openStream(), output); return output.toString(); } public static void main(String[] args) throws URISyntaxException, IOException { System.out.println(googleHits("odp")); } } The following exception is thrown: Exception in thread "main" java.lang.NullPointerException at odp.compling.Utils.googleHits(Utils.java:48) at odp.compling.Utils.main(Utils.java:59) What am I doing incorrectly? Should I be defining an entire object for the Json return? That seems excessive, given that all I want to do is get one value. For reference: the returned JSON structure.

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  • ArrayIndexOutOfBoundsException trying to access data

    - by Eggy
    I am getting an array index out of bounds exception in the following code: for (int i=1; i<11; i++) { int a[][] = new int[10][3]; double LeftTrim = 1.0; double RightTrim = 1.0; a [i][0]=(int) (LeftTrim*((i)*25)); a [i][1]=(int) (RightTrim*((i)*25)); a [i][2]= 5000; //leftWheel, rightWheel, Milliseconds myf.setWheelVelocities(a[i][0], a[i][1], a[i][2]); JOptionPane.showMessageDialog(null, + (a [i][0] + a [i][1])/2 + "wheel velocities" + " | " + a [i][2] + " Milliseconds" + " Click OK to continue..."); } Every-time I reach the 9th increment Eclipse gives me the error "Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 10" I have to test the velocity up to 250, but when I reach 225 and I click 'Ok' on 'Click ok to continue..." this error shows up! Am I going out of the array bounds or something? Thank you!

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  • Find messages from certain key till certain key while being able to remove stale keys.

    - by Alfred
    My problem Let's say I add messages to some sort of datastructure: 1. "dude" 2. "where" 3. "is" 4. "my" 5. "car" Asking for messages from index[4,5] should return: "my","car". Next let's assume that after a while I would like to purge old messages because they aren't useful anymore and I want to save memory. Let's say at time x messages[1-3] became stale. I assume that it would be most efficient to just do the deletion once every x seconds. Next my datastructure should contain: 4. "my" 5. "car" My solution? I was thinking of using a concurrentskiplistset or concurrentskiplist map. Also I was thinking of deleting the old messages from inside a newSingleThreadScheduledExecutor. I would like to know how you would implement(efficiently/thread-safe) this or maybe use a library?

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  • Creating a OS X Cocoa App Web View in Xcode 5.0.1

    - by user1822824
    I created a HTML5 web app that I’m trying to wrap in a web view and submit to the Mac App Store. I’ve done the following: 1) Opened Xcode 5.0.1 and selected “Create a new Xcode project” 2) Under “OS X” I selected “Application” then I selected “Cocoa Application” then “Next” 3) I entered a “Product Name” and a “Company Identifier” then selected “Next” (I left all the other settings untouched) then “Create” 4) Under “General” “Deployment Info” “Deployment Target” I selected 10.6 — because I want the app to be compatible with all versions of OS X that support the Mac App Store 5) I clicked “MainMenu.xib” and selected “Window - My App” 6) From the “Object library” I drug the “Web View” object into my window and made it fill the window size 7) I saved my project and click the Play button in the upper left corner of Xcode The app tries to open but freezes. I don’t get an error in Xcode but it does open “main.m” and highlight “return NSApplicationMain(argc, argv);” in green and says “Thread 1: signal SIGABRT” I was hoping that someone could clarify why this isn’t working? And provide me with the last step to link the web view object? I searched Google and found tutorials for iOS and a few for OS X but for different versions of Xcode.

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  • .NET: bool vs enum as a method parameter

    - by Julien Lebosquain
    Each time I'm writing a method that takes a boolean parameter representing an option, I find myself thinking: "should I replace this by an enum which would make reading the method calls much easier?". Consider the following with an object that takes a parameter telling whether the implementation should use its thread-safe version or not (I'm not asking here if this way of doing this is good design or not, only the use of the boolean): public void CreateSomeObject(bool makeThreadSafe); CreateSomeObject(true); When the call is next to the declaration the purpose of the parameter seems of course obvious. When it's in some third party library you barely know, it's harder to immediately see what the code does, compared to: public enum CreationOptions { None, MakeThreadSafe } public void CreateSomeObject(CreationOptions options); CreateSomeObject(CreationOptions.MakeThreadSafe); which describes the intent far better. Things get worse when there's two boolean parameters representing options. See what happened to ObjectContext.SaveChanges(bool) between Framework 3.5 and 4.0. It has been obsoleted because a second option has been introduced and the whole thing has been converted to an enum. While it seems obvious to use an enumeration when there's three elements or more, what's your opinion and experiences about using an enum instead a boolean in these specific cases?

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  • Calling a method at a specific interval rate in C++

    - by Aetius
    This is really annoying me as I have done it before, about a year ago and I cannot for the life of me remember what library it was. Basically, the problem is that I want to be able to call a method a certain number of times or for a certain period of time at a specified interval. One example would be I would like to call a method "x" starting from now, 10 times, once every 0.5 seconds. Alternatively, call method "x" starting from now, 10 times, until 5 seconds have passed. Now I thought I used a boost library for this functionality but I can't seem to find it now and feeling a bit annoyed. Unfortunately I can't look at the code again as I'm not in possession of it any more. Alternatively, I could have dreamt this all up and it could have been proprietary code. Assuming there is nothing out there that does what I would like, what is currently the best way of producing this behaviour? It would need to be high-resolution, up to a millisecond. It doesn't matter if it blocks the thread that it is executed from or not. Thanks!

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  • Input In Java- How does it work?

    - by Nir Avnon
    Hey guys, with a lot of help from you i was managed to write this nice code (I'm new in it, so kind of exciting.. :) ) And still I have not understand how can I input this code. first of all, I get an this error in the console line (I'm using Eclipse): Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0 at NumberConverter.main(NumberConverter.java:5). What does that mean? I just want to chack whether it works, and I can't call the function/program any how. I used to call in an "old fashion way", like in scheme, to the function that I wrote and see if something happens. How does it work in java? Do we call the program itself? function? what and where do we write? -I want to chack if it works, doesn't matter how, and I'll be glad to know how can I plugin input. Thank you so much! public class NumberConverter{ public static void main(String[] args) { int i = Integer.parseInt(args[0]); toBinary(i); toOctal(i); toHex(i); } public static void toBinary(int int1){ System.out.println(int1 + " in binary is"); System.out.println(Integer.toBinaryString(int1)); } public static void toOctal(int int1){ System.out.println(int1 + " in octal is"); System.out.println(Integer.toOctalString(int1)); } public static void toHex(int int1){ System.out.println(int1 + " in hex is"); System.out.println(Integer.toHexString(int1)); } }

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  • Looping through a method without for/foreach/while

    - by RichK
    Is there a way of calling a method/lines of code multiple times not using a for/foreach/while loop? For example, if I were to use to for loop: int numberOfIterations = 6; for(int i = 0; i < numberOfIterations; i++) { DoSomething(); SomeProperty = true; } The lines of code I'm calling don't use 'i' and in my opinion the whole loop declaration hides what I'm trying to do. This is the same for a foreach. I was wondering if there's a looping statement I can use that looks something like: do(6) { DoSomething(); SomeProperty = true; } It's really clear that I just want to execute that code 6 times and there's no noise involving index instantiating and adding 1 to some arbitrary variable. As a learning exercise I have written a static class and method: Do.Multiple(int iterations, Action action) Which works but scores very highly on the pretentious scale and I'm sure my peers wouldn't approve. I'm probably just being picky and a for loop is certainly the most recognisable, but as a learning point I was just wondering if there (cleaner) alternatives. Thanks. (I've had a look at this thread, but it's not quite the same) http://stackoverflow.com/questions/2248985/using-ienumerable-without-foreach-loop

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  • java.lang.IllegalStateException: The content of the adapter has changed but ListView.... inspite of calling notifydatasetchanged()

    - by Mistaken
    What are the best practices to be followed to update the contents of a listactivty by a background thread (Async Task) ? 1) Am calling the notifyDataSetChanged() to update the adapter as soon as i manipulate the contents of the adapter but still my app force closes while the user scrolls or click on the list. Any pointers to prevent this would be very helpfull. Logcat: java.lang.IllegalStateException: The content of the adapter has changed but ListView did not receive a notification. 2) Where exaclty should i update contents of the listactivity ? inside the doInBackground() or onProgressUpdate()? 3) Am experiencing regular crashes when the user clicks the list item. So will disabling click events on the listactivty during the background operation solve the problem ? If so am not sure how to remove or set item click listeners dynamically to the listactivity. Please instruct me on the too. 4) I dont think blocking all ui interactions during the background async task execution is the only way to solve the problem. I know there is a simple way of doing this but need some help. Thanks in advance. This is my onCreate... protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.fa); tvStatus=(TextView) findViewById(R.id.tvStatus); adapter = new SimpleAdapter( this, mostPopularList, R.layout.list_item, new String[] {"title","author","views","date"}, new int[] {R.id.textView1,R.id.textView2,R.id.textView4,R.id.textView3}); //populateList(); setListAdapter(adapter); } My async task... private class LongOperation extends AsyncTask<String, Void, String> { @Override protected String doInBackground(String... params) { // code for adding new listactivty items } @Override protected void onPostExecute(String networkStatus) { adapter.notifyDataSetChanged(); } @Override protected void onPreExecute() { } @Override protected void onProgressUpdate(Void... values) { } }

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  • Lack of understanding crash report

    - by Alan Lai
    I have this crash report. Incident Identifier: CA9E350A-C842-4349-AAD8-E9E62E93BDD1 CrashReporter Key: 360bc129d2f79a48e291eb5ca38b24e822ed5b6b Hardware Model: xxx Process: OrientalDailyiOS [1502] Path: /var/mobile/Applications/39480A57-68FF-4C46-8445-340EFE204119/OrientalDailyiOS.app/OrientalDailyiOS Identifier: OrientalDailyiOS Version: ??? (???) Code Type: ARM (Native) Parent Process: launchd [1] Date/Time: 2012-10-14 15:49:10.884 -0700 OS Version: iOS 6.0 (10A403) Report Version: 104 Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Crashed Thread: 0 Last Exception Backtrace: 0 CoreFoundation 0x37a0a29e __exceptionPreprocess + 158 1 libobjc.A.dylib 0x34e3197a objc_exception_throw + 26 2 CoreFoundation 0x37955b70 -[__NSArrayM objectAtIndex:] + 160 3 OrientalDailyiOS 0x00064fdc -[Main_NewsDetail viewDidLoad] (Main_NewsDetail.m:43) 4 UIKit 0x386cb590 -[UIViewController loadViewIfRequired] + 360 5 UIKit 0x38757336 -[UIViewController shouldAutorotate] + 22 6 UIKit 0x38798cd4 -[UIWindowController transition:fromViewController:toViewController:target:didEndSelector:] + 1540 7 UIKit 0x38797fca -[UIViewController presentViewController:withTransition:completion:] + 3390 8 UIKit 0x388ba252 -[UIViewController presentModalViewController:animated:] + 26 9 Foundation 0x34364a6a __NSFireDelayedPerform + 446 10 CoreFoundation 0x379df5da __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 10 11 CoreFoundation 0x379df28c __CFRunLoopDoTimer + 268 12 CoreFoundation 0x379ddefc __CFRunLoopRun + 1228 13 CoreFoundation 0x37950eb8 0x37948000 + 36536 14 CoreFoundation 0x37950d44 CFRunLoopRunInMode + 100 15 GraphicsServices 0x373e32e6 GSEventRunModal + 70 16 UIKit 0x387002fc 0x386a9000 + 357116 17 OrientalDailyiOS 0x0005fac2 main (main.m:16) 18 OrientalDailyiOS 0x0005fa84 0x5e000 + 6788 However, I couldn't know where is error, I play around with my apps but show no error. I also tried iOS 6 with iPad, no problem. what apple feedback was We found that your app crashed on iPad running iOS 6, which is not in compliance with the App Store Review Guidelines. Your app crashed on both Wi-Fi and cellular networks when we: 1. Launch the app. 2. Tap any item on main page. 3. App crashes.

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  • Templates, Function Pointers and C++0x

    - by user328543
    One of my personal experiments to understand some of the C++0x features: I'm trying to pass a function pointer to a template function to execute. Eventually the execution is supposed to happen in a different thread. But with all the different types of functions, I can't get the templates to work. #include `<functional`> int foo(void) {return 2;} class bar { public: int operator() (void) {return 4;}; int something(int a) {return a;}; }; template <class C> int func(C&& c) { //typedef typename std::result_of< C() >::type result_type; typedef typename std::conditional< std::is_pointer< C >::value, std::result_of< C() >::type, std::conditional< std::is_object< C >::value, std::result_of< typename C::operator() >::type, void> >::type result_type; result_type result = c(); return result; } int main(int argc, char* argv[]) { // call with a function pointer func(foo); // call with a member function bar b; func(b); // call with a bind expression func(std::bind(&bar::something, b, 42)); // call with a lambda expression func( [](void)->int {return 12;} ); return 0; } The result_of template alone doesn't seem to be able to find the operator() in class bar and the clunky conditional I created doesn't compile. Any ideas? Will I have additional problems with const functions?

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  • Updating a C# 2.0 events example to be idiomatic with C# 3.5?

    - by Damien Wildfire
    I have a short events example from .NET 2.0 that I've been using as a reference point for a while. We're now upgrading to 3.5, though, and I'm not clear on the most idiomatic way to do things. How would this simple events example get updated to reflect idioms that are now available in .NET 3.5? // Args class. public class TickArgs : EventArgs { private DateTime TimeNow; public DateTime Time { set { TimeNow = value; } get { return this.TimeNow; } } } // Producer class that generates events. public class Metronome { public event TickHandler Tick; public delegate void TickHandler(Metronome m, TickArgs e); public void Start() { while (true) { System.Threading.Thread.Sleep(3000); if (Tick != null) { TickArgs t = new TickArgs(); t.Time = DateTime.Now; Tick(this, t); } } } } // Consumer class that listens for events. public class Listener { public void Subscribe(Metronome m) { m.Tick += new Metronome.TickHandler(HeardIt); } private void HeardIt(Metronome m, TickArgs e) { System.Console.WriteLine("HEARD IT AT {0}",e.Time); } } // Example. public class Test { static void Main() { Metronome m = new Metronome(); Listener l = new Listener(); l.Subscribe(m); m.Start(); } }

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  • cuda 5.0 namespaces for contant memory variable usage

    - by Psypher
    In my program I want to use a structure containing constant variables and keep it on device all long as the program executes to completion. I have several header files containing the declaration of 'global' functions and their respective '.cu' files for their definitions. I kept this scheme because it helps me contain similar code in one place. e.g. all the 'device' functions required to complete 'KERNEL_1' are separated from those 'device' functions required to complete 'KERNEL_2' along with kernels definitions. I had no problems with this scheme during compilation and linking. Until I encountered constant variables. I want to use the same constant variable through all kernels and device functions but it doesn't seem to work. ########################################################################## CODE EXAMPLE ########################################################################### filename: 'common.h' -------------------------------------------------------------------------- typedef struct { double height; double weight; int age; } __CONSTANTS; __constant__ __CONSTANTS d_const; --------------------------------------------------------------------------- filename: main.cu --------------------------------------------------------------------------- #include "common.h" #include "gpukernels.h" int main(int argc, char **argv) { __CONSTANTS T; T.height = 1.79; T.weight = 73.2; T.age = 26; cudaMemcpyToSymbol(d_consts, &T, sizeof(__CONSTANTS)); test_kernel <<< 1, 16 >>>(); cudaDeviceSynchronize(); } --------------------------------------------------------------------------- filename: gpukernels.h --------------------------------------------------------------------------- __global__ void test_kernel(); --------------------------------------------------------------------------- filename: gpukernels.cu --------------------------------------------------------------------------- #include <stdio.h> #include "gpukernels.h" #include "common.h" __global__ void test_kernel() { printf("Id: %d, height: %f, weight: %f\n", threadIdx.x, d_const.height, d_const.weight); } When I execute this code, the kernel executes, displays the thread ids, but the constant values are displayed as zeros. How can I fix this?

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  • Multithreading for loop while maintaining order

    - by David
    I started messing around with multithreading for a CPU intensive batch process I'm running. Essentially I'm trying to condense multiple single page tiffs into single PDF documents. This works fine with a foreach loop or standard iteration but can be very slow for several 100 page documents. I tried the following based on a some examples I found to use multithreading and it has significant performance improvements however it obliterates the page order instead of 1,2,3,4 it will be 1,3,4,2,6,5 on what thread completes first. My question is how would I utilize this technique while maintaining the page order and if I can will it negate the performance benefit of the multithreading? Thank you in advance. PdfDocument doc = new PdfDocument(); string mail = textBox1.Text; string[] split = mail.Split(new string[] { Environment.NewLine }, StringSplitOptions.None); int counter = split.Count(); // Source must be array or IList. var source = Enumerable.Range(0, 100000).ToArray(); // Partition the entire source array. var rangePartitioner = Partitioner.Create(0, counter); double[] results = new double[counter]; // Loop over the partitions in parallel. Parallel.ForEach(rangePartitioner, (range, loopState) => { // Loop over each range element without a delegate invocation. for (int i = range.Item1; i < range.Item2; i++) { f_prime = split[i].Replace(" " , ""); PdfPage page = doc.AddPage(); XGraphics gfx = XGraphics.FromPdfPage(page); XImage image = XImage.FromFile(f_prime); double x = 0; gfx.DrawImage(image, x, 0); } });

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  • Does the Java Memory Model (JSR-133) imply that entering a monitor flushes the CPU data cache(s)?

    - by Durandal
    There is something that bugs me with the Java memory model (if i even understand everything correctly). If there are two threads A and B, there are no guarantees that B will ever see a value written by A, unless both A and B synchronize on the same monitor. For any system architecture that guarantees cache coherency between threads, there is no problem. But if the architecture does not support cache coherency in hardware, this essentially means that whenever a thread enters a monitor, all memory changes made before must be commited to main memory, and the cache must be invalidated. And it needs to be the entire data cache, not just a few lines, since the monitor has no information which variables in memory it guards. But that would surely impact performance of any application that needs to synchronize frequently (especially things like job queues with short running jobs). So can Java work reasonably well on architectures without hardware cache-coherency? If not, why doesn't the memory model make stronger guarantees about visibility? Wouldn't it be more efficient if the language would require information what is guarded by a monitor? As i see it the memory model gives us the worst of both worlds, the absolute need to synchronize, even if cache coherency is guaranteed in hardware, and on the other hand bad performance on incoherent architectures (full cache flushes). So shouldn't it be more strict (require information what is guarded by a monitor) or more lose and restrict potential platforms to cache-coherent architectures? As it is now, it doesn't make too much sense to me. Can somebody clear up why this specific memory model was choosen? EDIT: My use of strict and lose was a bad choice in retrospect. I used "strict" for the case where less guarantees are made and "lose" for the opposite. To avoid confusion, its probably better to speak in terms of stronger or weaker guarantees.

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