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  • Stream writing lags my GUI

    - by blez
    I have a thread that dequeues data from a queue and write it to another application's STDIN. I'm using Stream, but with .Write and even .BeginWrite, when I send 1mb chunks to the second app, my GUI gets laggy for ~1sec. Why?

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  • java.util.concurrent.ThreadPoolExecutor strange logic

    - by rodrigoap
    Look ath this method of ThreadPoolExcecutor: public void execute(Runnable command) { ... if (runState == RUNNING && workQueue.offer(command)) { if (runState != RUNNING || poolSize == 0) ensureQueuedTaskHandled(command); } ... } It check that runState is RUNNING and then the oposite. As I'm trying to do some tuning on a SEDA like model I wanted to understand the internals of the thread pool. Do you think this code is correct?

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  • pthread and child process data sharing in C

    - by mustafabattal
    hi everyone, my question is somewhat conceptual, how is parent process' data shared with child process created by a "fork()" call or with a thread created by "pthread_create()" for example, are global variables directly passed into child process and if so, does modification on that variable made by child process effect value of it in parent process? i appreciate partial and complete answers in advance, if i'm missing any existing resource, i'm sorry, i've done some search on google but couldn't find good results thanks again for your time and answers

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  • When does Visual Studio call target AfterBuild & BeforeBuild? And how is it handled when these targe

    - by Nam Gi VU
    Hi Fiburt, Today I meet a similar problem and it reminds me about this thread. In Visual Studio, if we open the .csproj file, we see that they tell us to uncomment the two targets AfterBuild and BeforeBuild so as to execute them after and before the build of the current project accordingly. My questions are: Where are these two targets called in Visual Studio? And how is it handled if the targets are not defined (be commented out) ?

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  • Windows Azure SDK - ASPProviders example

    - by David
    Hi, since the new SDK 1.1 is missing the tutorial for "ASPProviders", i am currently asking myself how i would implement a "azure session state provider" ( this is the path in the "old" SDK: C:\Program Files\Windows Azure SDK\v1.0\Samples\AspProviders ) Related threads: http://stackoverflow.com/questions/1023108/how-does-microsoft-azure-handle-session-state http://social.msdn.microsoft.com/Forums/en-US/windowsazure/thread/2d1340ed-0ad0-456a-b069-aa6b85672102/ Has anyone an idea or even the old example project and could post some snippets of the config here?

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  • java concurrency: many writers, one reader

    - by Janning
    I need to gather some statistics in my software and i am trying to make it fast and correct, which is not easy (for me!) first my code so far with two classes, a StatsService and a StatsHarvester public class StatsService { private Map<String, Long> stats = new HashMap<String, Long>(1000); public void notify ( String key ) { Long value = 1l; synchronized (stats) { if (stats.containsKey(key)) { value = stats.get(key) + 1; } stats.put(key, value); } } public Map<String, Long> getStats ( ) { Map<String, Long> copy; synchronized (stats) { copy = new HashMap<String, Long>(stats); stats.clear(); } return copy; } } this is my second class, a harvester which collects the stats from time to time and writes them to a database. public class StatsHarvester implements Runnable { private StatsService statsService; private Thread t; public void init ( ) { t = new Thread(this); t.start(); } public synchronized void run ( ) { while (true) { try { wait(5 * 60 * 1000); // 5 minutes collectAndSave(); } catch (InterruptedException e) { e.printStackTrace(); } } } private void collectAndSave ( ) { Map<String, Long> stats = statsService.getStats(); // do something like: // saveRecords(stats); } } At runtime it will have about 30 concurrent running threads each calling notify(key) about 100 times. Only one StatsHarvester is calling statsService.getStats() So i have many writers and only one reader. it would be nice to have accurate stats but i don't care if some records are lost on high concurrency. The reader should run every 5 Minutes or whatever is reasonable. Writing should be as fast as possible. Reading should be fast but if it locks for about 300ms every 5 minutes, its fine. I've read many docs (Java concurrency in practice, effective java and so on), but i have the strong feeling that i need your advice to get it right. I hope i stated my problem clear and short enough to get valuable help.

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  • Iterating Collection In Two Threads

    - by ChloeRadshaw
    This question relates both to C# and Java If you have a collection which is not modified and that collection reference is shared between two threads what happens when you iterate on each thread?? ThreadA: Collection.iterator ThreadA: Collection.moveNext ThreadB: Collection.iterator ThreadB: Collection.moveNext Will threadB see the first element? Is the iterator always reset when it is requested? What happens if this is interleaved so movenext and item is interleaved? Is there a danger that you dont process all elements??

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  • What free tools or strategies can help debug a multi-threading corruption bug?

    - by WilliamKF
    I have a client server application with multi-threading. The server side is failing with a std::list getting corrupted resulting in a SEGV. I suspect that there is some kind of cross thread timing issue going on where the two threads are updating the std::list at the same time and causing it to be corrupted. Please suggest free tools to track this down or strategies that might be helpful.

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  • Optimising movement on hex grid

    - by Mloren
    I am making a turn based hex-grid game. The player selects units and moves them across the hex grid. Each tile in the grid is of a particular terrain type (eg desert, hills, mountains, etc) and each unit type has different abilities when it comes to moving over the terrain (e.g. some can move over mountains easily, some with difficulty and some not at all). Each unit has a movement value and each tile takes a certain amount of movement based on its terrain type and the unit type. E.g it costs a tank 1 to move over desert, 4 over swamp and cant move at all over mountains. Where as a flying unit moves over everything at a cost of 1. The issue I have is that when a unit is selected, I want to highlight an area around it showing where it can move, this means working out all the possible paths through the surrounding hexes, how much movement each path will take and lighting up the tiles based on that information. I got this working with a recursive function and found it took too long to calculate, I moved the function into a thread so that it didn't block the game but still it takes around 2 seconds for the thread to calculate the moveable area for a unit with a move of 8. Its over a million recursions which obviously is problematic. I'm wondering if anyone has an clever ideas on how I can optimize this problem. Here's the recursive function I'm currently using (its C# btw): private void CalcMoveGridRecursive(int nCenterIndex, int nMoveRemaining) { //List of the 6 tiles adjacent to the center tile int[] anAdjacentTiles = m_ThreadData.m_aHexData[nCenterIndex].m_anAdjacentTiles; foreach(int tileIndex in anAdjacentTiles) { //make sure this adjacent tile exists if(tileIndex == -1) continue; //How much would it cost the unit to move onto this adjacent tile int nMoveCost = m_ThreadData.m_anTerrainMoveCost[(int)m_ThreadData.m_aHexData[tileIndex].m_eTileType]; if(nMoveCost != -1 && nMoveCost <= nMoveRemaining) { //Make sure the adjacent tile isnt already in our list. if(!m_ThreadData.m_lPassableTiles.Contains(tileIndex)) m_ThreadData.m_lPassableTiles.Add(tileIndex); //Now check the 6 tiles surrounding the adjacent tile we just checked (it becomes the new center). CalcMoveGridRecursive(tileIndex, nMoveRemaining - nMoveCost); } } } At the end of the recursion, m_lPassableTiles contains a list of the indexes of all the tiles that the unit can possibly reach and they are made to glow. This all works, it just takes too long. Does anyone know a better approach to this?

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  • Find consecutive "//" in regex in JavaScript

    - by iOnline247
    I gave it a college try, but I'm stumped. I'm trying to find consecutive slashes within a string. The rest of the regex works great, but the last part I can't quite get. Here's what I have: val.match( /^[\/]|[~"#%&*:<>?\\{|}]|[\/|.]$/ ) and finding this thread, I decided to update my code to no avail: RegEx to find two or more consecutive chars val.match( /^[\/]|[\/]{2,}|[~"#%&*:<>?\\{|}]|[\/|.]$/ ) What do I need to get this thing going?

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  • Django - serving and managing permissions for static content

    - by kRON
    I have certain documents that I want to limit access to through Django to authorized users with permissions only. If I'm going to use Django as a proxy to serve static files in a view, what are the implications? I'm used to serving static files in Apache and configuring that my media is served without any handlers, but what happens if someone starts downloading 500mb through my Django proxy? Will my Django thread be locked for that user until he recieves the 500mb response?

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  • How to solve Python memory leak when using urrlib2?

    - by b_m
    Hi, I'm trying to write a simple Python script for my mobile phone to periodically load a web page using urrlib2. In fact I don't really care about the server response, I'd only like to pass some values in the URL to the PHP. The problem is that Python for S60 uses the old 2.5.4 Python core, which seems to have a memory leak in the urrlib2 module. As I read there's seems to be such problems in every type of network communications as well. This bug have been reported here a couple of years ago, while some workarounds were posted as well. I've tried everything I could find on that page, and with the help of Google, but my phone still runs out of memory after ~70 page loads. Strangely the Garbege Collector does not seem to make any difference either, except making my script much slower. It is said that, that the newer (3.1) core solves this issue, but unfortunately I can't wait a year (or more) for the S60 port to come. here's how my script looks after adding every little trick I've found: import urrlib2, httplib, gc while(true): url = "http://something.com/foo.php?parameter=" + value f = urllib2.urlopen(url) f.read(1) f.fp._sock.recv=None # hacky avoidance f.close() del f gc.collect() Any suggestions, how to make it work forever without getting the "cannot allocate memory" error? Thanks for advance, cheers, b_m update: I've managed to connect 92 times before it ran out of memory, but It's still not good enough. update2: Tried the socket method as suggested earlier, this is the second best (wrong) solution so far: class UpdateSocketThread(threading.Thread): def run(self): global data while 1: url = "/foo.php?parameter=%d"%data s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect(('something.com', 80)) s.send('GET '+url+' HTTP/1.0\r\n\r\n') s.close() sleep(1) I tried the little tricks, from above too. The thread closes after ~50 uploads (the phone has 50MB of memory left, obviously the Python shell has not.) UPDATE: I think I'm getting closer to the solution! I tried sending multiple data without closing and reopening the socket. This may be the key since this method will only leave one open file descriptor. The problem is: import socket s=socket.socket(socket.AF_INET, socket.SOCK_STREAM) socket.connect(("something.com", 80)) socket.send("test") #returns 4 (sent bytes, which is cool) socket.send("test") #4 socket.send("test") #4 socket.send("GET /foo.php?parameter=bar HTTP/1.0\r\n\r\n") #returns the number of sent bytes, ok socket.send("GET /foo.php?parameter=bar HTTP/1.0\r\n\r\n") #returns 0 on the phone, error on Windows7* socket.send("GET /foo.php?parameter=bar HTTP/1.0\r\n\r\n") #returns 0 on the phone, error on Windows7* socket.send("test") #returns 0, strange... *: error message: 10053, software caused connection abort Why can't I send multiple messages??

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  • How does volatile actually work?

    - by FredOverflow
    Marking a variable as volatile in Java ensures that every thread sees the value that was last written to it instead of some stale value. I was wondering how this is actually achieved. Does the JVM emit special instructions that flush the CPU cashes or something?

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  • Is there an use case for non-blocking receive when I have threads?

    - by Gabriel Šcerbák
    I know non-blocking receive is not used as much in message passing, but still some intuition tells me, it is needed. Take for example GUI event driven applications, you need some way to wait for a message in a non-blocking way, so your program can execute some computations. One of the ways to solve this is to have a special thread with message queue. Is there some use case, where you would really need non-blocking receive even if you have threads?

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  • When I really need to use [NSThread sleepForTimeInterval:1];

    - by Timbo
    Hi there, I have a program that needs to use sleep. Like really needs to. In lieu of spending ages explaining why, suffice to say that it needs it. Now I'm told to split off my code into a separate thread if it requires sleep so I don't lose interface responsiveness, so I've started learning how to use NSThread. I've created a brand new program that is conceptual so to solve the issue for this example will help me in my real program. Short story is I have a class, it has instance variables and I need a loop with a sleep to be depended on the value of that instance variable. Here's what I've put together anyway, your help is very much appreciated :) Cheers Tim /// Start Test1ViewController.h /// #import <UIKit/UIKit.h> @interface Test1ViewController : UIViewController { UILabel* label; } @property (assign) IBOutlet UILabel *label; @end /// End Test1ViewController.h /// /// Start Test1ViewController.m /// #import "Test1ViewController.h" #import "MyClass.h" @implementation Test1ViewController @synthesize label; - (void)viewDidAppear:(BOOL)animated { [super viewDidAppear:animated]; label.text = @"1"; [NSThread detachNewThreadSelector:@selector(backgroundProcess) toTarget:self withObject:nil]; } - (void)backgroundProcess { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; // Create an instance of a class that will eventually store a whole load of variables MyClass *aMyClassInstance = [MyClass new]; [aMyClassInstance createMyClassInstance:(@"Timbo")]; while (aMyClassInstance.myVariable--) { NSLog(@"blah = %i",aMyClassInstance.myVariable); label.text = [NSString stringWithFormat:@"blah = %d", aMyClassInstance.myVariable]; //how do I pass the new value out to the updateLabel method, or reference aMyClassInstance.myVariable? [self performSelectorOnMainThread:@selector(updateLabel) withObject:nil waitUntilDone:NO]; //the sleeping of the thread is absolutely mandatory and must be worked around. The whole point of using NSThread is so I can have sleeps [NSThread sleepForTimeInterval:1]; } [pool release]; } - (void)updateLabel {label.text = [NSString stringWithFormat:@"blah = %d", aMyClassInstance.myVariable]; // be nice if i could } - (void)didReceiveMemoryWarning {[super didReceiveMemoryWarning];} - (void)viewDidUnload {} - (void)dealloc {[super dealloc];} @end /// End Test1ViewController.m /// /// Start MyClass.h /// #import <Foundation/Foundation.h> @interface MyClass : NSObject { NSString* name; int myVariable; } @property int myVariable; @property (assign) NSString *name; - (void) createMyClassInstance: (NSString*)withName; - (int) changeVariable: (int)toAmount; @end /// End MyClass.h /// /// Start MyClass.h /// #import "MyClass.h" @implementation MyClass @synthesize name, myVariable; - (void) createMyClassInstance: (NSString*)withName{ name = withName; myVariable = 10; } - (int) changeVariable: (int)toAmount{ myVariable = toAmount; return toAmount; } @end /// End MyClass.h ///

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  • Can't get InputStream read to block...

    - by mark dufresne
    I would like the input stream read to block instead of reading end of stream (-1). Is there a way to configure the stream to do this? Here's my Servlet code: PrintWriter out = response.getWriter(); BufferedReader in = request.getReader(); try { String line; int loop = 0; while (loop < 20) { line = in.readLine(); lgr.log(Level.INFO, line); out.println("<" + loop + "html>"); Thread.sleep(1000); loop++; // } } catch (InterruptedException ex) { lgr.log(Level.SEVERE, null, ex); } finally { out.close(); } Here's my Midlet code: private HttpConnection conn; InputStream is; OutputStream os; private boolean exit = false; public void run() { String url = "http://localhost:8080/WebApplication2/NewServlet"; try { conn = (HttpConnection) Connector.open(url); is = conn.openInputStream(); os = conn.openOutputStream(); StringBuffer sb = new StringBuffer(); int c; while (!exit) { os.write("<html>\n".getBytes()); while ((c = is.read()) != -1) { sb.append((char) c); } System.out.println(sb.toString()); sb.delete(0, sb.length() - 1); try { Thread.sleep(1000); } catch (InterruptedException ex) { ex.printStackTrace(); } } os.close(); is.close(); conn.close(); } catch (IOException ex) { ex.printStackTrace(); } } I've tried InputStream.read, but it doesn't block either, it returns -1 as well. I'm trying to keep the I/O streams on either side alive. I want the servlet to wait for input, process the input, then send back a response. In the code above it should do this 20 times. thanks for any help

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  • How to retry opening a properties file in Java

    - by Hoggy
    I'm trying to handle an FileNotFoundException in Java by suspending the thread for x seconds and rereading the file. The idea behind this is to edit properties during runtime. The problem is that the programm simply terminates. Any idea how to realize this solution?

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  • good word whitelist to override bad word black list

    - by dangerousguy
    I've read through the discussion here... http://stackoverflow.com/questions/273516/how-do-you-implement-a-good-profanity-filter I've decided to implement a bad word filter using the badlist referenced in that thread. However I'm thinking about the scunthorpe problem. (see wikipedia I can't post the link, I'm a new user) Is there a white list of words like scunthorpe and manuscript that I can use to override a black list? (not interested in discussions about sensorship etc)

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  • Animate tray icon while processing

    - by sjlewis
    How can I animate the tray icon while the main application is processing? I already tried the suggestion here, but the icon does not animate during process. I also tried putting the animation in a separate thread but still no luck.

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