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  • Measuring time spent in application / thread

    - by Adamski
    I am writing a simulation in Java whereby objects act under Newtonian physics. An object may have a force applied to it and the resulting velocity causes it to move across the screen. The nature of the simulation means that objects move in discrete steps depending on the time ellapsed between the current and previous iteration of the animation loop; e.g public void animationLoop() { long prev = System.currentTimeMillis(); long now; while(true) { long now = System.currentTimeMillis(); long deltaMillis = now - prev; prev = now; if (deltaMillis > 0) { // Some time has passed for (Mass m : masses) { m.updatePosition(deltaMillis); } // Do all repaints. } } } A problem arises if the animation thread is delayed in some way causing a large amount of time to ellapse (the classic case being under Windows whereby clicking and holding on minimise / maximise prevents a repaint), which causes objects to move at an alarming rate. My question: Is there a way to determine the time spent in the animation thread rather than the wallclock time, or can anyone suggest a workaround to avoid this problem? My only thought so far is to contstrain deltaMillis by some upper bound.

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  • Best way to implement game loop without freezing UI thread

    - by Matt H
    I'm trying to make a simple 2D game in Java. So far I have a JFrame, with a menubar, and a class which extends JPanel and overrides it's paint method. Now, I need to get a game loop going, where I will update the position of images and so on. However, I'm stuck at how best to achieve this. Should I use multi-threading, because surely, if you put an infinite loop on the main thread, the UI (and thus my menu bar) will freeze up? Here's my code so far: import java.awt.Color; import java.awt.Graphics; import javax.swing.JPanel; @SuppressWarnings("serial") public class GameCanvas extends JPanel { public void paint(Graphics g) { while (true) { g.setColor(Color.DARK_GRAY); try { Thread.sleep(100); } catch (InterruptedException e) { e.printStackTrace(); } } } } import javax.swing.JFrame; import javax.swing.JMenu; import javax.swing.JMenuBar; import javax.swing.JMenuItem; @SuppressWarnings("serial") public class Main extends JFrame { GameCanvas canvas = new GameCanvas(); final int FRAME_HEIGHT = 400; final int FRAME_WIDTH = 400; public static void main(String args[]) { new Main(); } public Main() { super("Game"); JMenuBar menuBar = new JMenuBar(); JMenu fileMenu = new JMenu("File"); JMenuItem startMenuItem = new JMenuItem("Pause"); menuBar.add(fileMenu); fileMenu.add(startMenuItem); super.add(canvas); super.setVisible(true); super.setSize(FRAME_WIDTH, FRAME_WIDTH); super.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); super.setJMenuBar(menuBar); } } Any pointers/tips? Also, where should I put my loop? In my main class, or my GameCanvas class? Any help is appreciated, thanks.

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  • Static Logger in seperate thread?

    - by SirLenz0rlot
    Hi all, I've made my Logger, that logs a string, a static class with a static so I can call it from my entire project without having to make an instance of it. quite nice, but I want to make it run in a seperate thread, since accessing the file costs time is that possible somehow and what's the best way to do it? Its a bit of a short discription, but I hope the idea is clear. if not, please let me know. Thanks in advance! btw: any other improvements on my code are welcome as well, i have the feeling not everthing is as efficient as it can be: internal static class MainLogger { internal static void LogStringToFile(string logText) { DateTime timestamp = DateTime.Now; string str = timestamp.ToString("dd-MM-yy HH:mm:ss ", CultureInfo.InvariantCulture) + "\t" + logText + "\n"; const string filename = Constants.LOG_FILENAME; FileInfo fileInfo = new FileInfo(filename); if (fileInfo.Exists) { if (fileInfo.Length > Constants.LOG_FILESIZE) { File.Create(filename).Dispose(); } } else { File.Create(filename).Dispose(); } int i = 0; while(true) { try { using (StreamWriter writer = File.AppendText(filename)) { writer.WriteLine(str); } break; } catch (IOException) { Thread.Sleep(10); i++; if (i >= 8) { throw new IOException("Log file \"" + Constants.LOG_FILENAME + "\" not accessible after 5 tries"); } } } } } enter code here

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  • WP7 BarcodeManager - Invalid cross-thread access

    - by rpf
    I'm trying to use Windows Phone 7 Silverlight ZXing Barcode Scanning Library but I'm having some problems. I'm using a background worker to check the image, but when I do this: WP7BarcodeManager.ScanBarcode(this.Image, BarcodeResults_Finished); The code throws an exception: Invalid cross-thread access. Here is my code... void photoChooserTask_Completed(object sender, PhotoResult e) { if (e.TaskResult == TaskResult.OK) { ShowImage(); System.Windows.Media.Imaging.BitmapImage bmp = new System.Windows.Media.Imaging.BitmapImage(); bmp.SetSource(e.ChosenPhoto); imgCapture.Source = bmp; this.Image = new BitmapImage(); this.Image.SetSource(e.ChosenPhoto); progressBar.Visibility = System.Windows.Visibility.Visible; txtStatus.Visibility = System.Windows.Visibility.Collapsed; worker.RunWorkerAsync(); } else ShowMain(); } void worker_DoWork(object sender, DoWorkEventArgs e) { try { Thread.Sleep(2000); WP7BarcodeManager.ScanMode = com.google.zxing.BarcodeFormat.UPC_EAN; WP7BarcodeManager.ScanBarcode(this.Image, BarcodeResults_Finished); } catch (Exception ex) { Debug.WriteLine("Error processing image.", ex); } } How can I solve this?

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  • C#: Thread.CurrentThread.CurrentUICulture not working consistently

    - by xTRUMANx
    I've been working on a pet project on the weekends to learn more about C# and have encountered an odd problem when working with localization. To be more specific, the problem I have is with System.Threading.Thread.CurrentThread.CurrentUICulture. I've set up my app so that the user can quickly change the language of the app by clicking a menu item. The menu item in turn, saves the two-letter code for the language (e.g. "en", "fr", etc.) in a user setting called 'Language' and then restarts the application. Properties.Settings.Default.Language = "en"; Properties.Settings.Default.Save(); Application.Restart(); When the application is started up, the first line of code in the Form's constructor (even before InitializeComponent()) fetches the Language string from the settings and sets the CurrentUICulture like so: public Form1() { Thread.CurrentThread.CurrentUICulture = new CultureInfo(Properties.Settings.Default.Language); InitializeComponent(); } The thing is, this doesn't work consistently. Sometimes, all works well and the application loads the correct language based on the string saved in the settings file. Other times, it doesn't, and the language remains the same after the application is restarted. At first I thought that I didn't save the language before restarting the application but that is definitely not the case. When the correct language fails to load, if I were to close the application and run it again, the correct language would come up correctly. So this implies that the Language string has been saved but the CurrentUICulture assignment in my form constructor is having no effect sometimes. Any help? Is there something I'm missing of how threading works in C#? This could be machine-specific, so if it makes any difference I'm using Pentium Dual-Core CPU.

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  • whether rand_r is real thread safe?

    - by terry
    Well, rand_r function is supposed to be a thread safe function. However, by its implementation, I cannot believe it could make itself not change by other threads. Suppose that two threads will invoke rand_r in the same time with the same variable seed. So read-write race will occur. The code rand_r implemented by glibc is listed below. Anybody knows why rand_r is called thread safe? int rand_r (unsigned int *seed) { unsigned int next = *seed; int result; next *= 1103515245; next += 12345; result = (unsigned int) (next / 65536) % 2048; next *= 1103515245; next += 12345; result <<= 10; result ^= (unsigned int) (next / 65536) % 1024; next *= 1103515245; next += 12345; result <<= 10; result ^= (unsigned int) (next / 65536) % 1024; *seed = next; return result; }

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  • how to run TimerTask off main UI thread?

    - by huskyd97
    I am having trouble with a TimerTask Interfering with In App Purchasing (Async Tasks). I am weak with Threads, so I believe it is running on the main UI thread, eating up resources. How can I run this outside the UI thread? I have searched, and tried some suggestions using handlers. but seems like I get the same result, app gets really laggy. when I don't run this task (refreshes every 500mS), the activity runs smoothly, and there are no hangs during In app purchases. Your help is appreciated, code snippet below: public class DummyButtonClickerActivity extends Activity { protected Timer timeTicker = new Timer("Ticker"); private Handler timerHandler = new Handler(); protected int timeTickDown = 20; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.mainhd); // start money earned timer handler TimerTask tick = new TimerTask() { public void run() { myTickTask(); } }; timeTicker.scheduleAtFixedRate(tick, 0, 500); // 500 ms each } // End OnCreate protected void myTickTask() { if (timeTickDown == 0) { /// run my code here //total = total + _Rate; timerHandler.post(doUpdateTimeout); } else if(timeTickDown < 0) { // do nothing } timeTickDown--; } private Runnable doUpdateTimeout = new Runnable() { public void run() { updateTimeout(); } }; private void updateTimeout() { // reset tick timeTickDown = 2; // 2* 500ms == once a second } }

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  • Threads syncronization with ThreadPoolExecutor

    - by justme1
    I'm trying to implement some logic when I create main(father) thread witch executes several other threads. Then it waits for some condition which child threads creates. After condition is meet the father executes some more child threads. The problem that when I use wait/notify I have java.lang.IllegalMonitorStateException exception. Here is the code: public class MyExecutor { final static ArrayBlockingQueue<Runnable> queue = new ArrayBlockingQueue<Runnable>(10); final static ExecutorService svc = Executors.newFixedThreadPool(1); static final ThreadPoolExecutor threadPool = new ThreadPoolExecutor(5, 8, 10, TimeUnit.SECONDS, queue); public static void main(String[] args) throws InterruptedException { final MyExecutor me = new MyExecutor(); svc.execute(new Runnable() { public void run() { try { System.out.println("Main Thread"); me.execute(threadPool, 1); System.out.println("Main Thread waiting"); wait(); System.out.println("Main Thread notified"); me.execute(threadPool, 2); Thread.sleep(100); threadPool.shutdown(); threadPool.awaitTermination(20000, TimeUnit.SECONDS); } catch (InterruptedException e) { e.printStackTrace(); } } }); svc.shutdown(); svc.awaitTermination(10000, TimeUnit.SECONDS); System.out.println("Main Thread finished"); } public void execute(ThreadPoolExecutor tpe, final int id) { tpe.execute(new Runnable() { public void run() { try { System.out.println("Child Thread " + id); Thread.sleep(2000); System.out.println("Child Thread " + id + " finished"); notify(); } catch (InterruptedException e) { e.printStackTrace(); } } }); } } When I comment wait and notify line I have the following output: Main Thread Main Thread waiting Main Thread notified Child Thread 1 Child Thread 2 Child Thread 1 finished Child Thread 2 finished Main Thread finished

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  • is there a simple timed lock algorithm avoiding deadlock on multiple mutexes?

    - by Vicente Botet Escriba
    C++0x thread library or Boost.thread define a non-member variadic template function that locks all mutex at once that helps to avoid deadlock. template <class L1, class L2, class... L3> void lock(L1&, L2&, L3&...); The same can be applied to a non-member variadic template function try_lock_until, which locks all the mutex until a given time is reached that helps to avoid deadlock like lock(...). template <class Clock, class Duration, class L1, class L2, class... L3> void try_lock_until( const chrono::time_point<Clock,Duration>& abs_time, L1&, L2&, L3&...); I have an implementation that follows the same design as the Boost function boost::lock(...). But this is quite complex. As I can be missing something evident I wanted to know if: is there a simple timed lock algorithm avoiding deadlock on multiple mutexes? If no simple implementation exists, can this justify a proposal to Boost? P.S. Please avoid posting complex solutions.

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  • Another thread safe queue implementation

    - by jensph
    I have a class, Queue, that I tried to make thread safe. It has these three member variables: std::queue<T> m_queue; pthread_mutex_t m_mutex; pthread_cond_t m_condition; and a push and pop implemented as: template<class T> void Queue<T>::push(T value) { pthread_mutex_lock( &m_mutex ); m_queue.push(value); if( !m_queue.empty() ) { pthread_cond_signal( &m_condition ); } pthread_mutex_unlock( &m_mutex ); } template<class T> bool Queue<T>::pop(T& value, bool block) { bool rtn = false; pthread_mutex_lock( &m_mutex ); if( block ) { while( m_queue.empty() ) { pthread_cond_wait( &m_condition, &m_mutex ); } } if( !m_queue.empty() ) { value = m_queue.front(); m_queue.pop(); rtn = true; } pthread_mutex_unlock( &m_mutex ); return rtn; } Unfortunately there are occasional issues that may be the fault of this code. That is, there are two threads and sometimes thread 1 never comes out of push() and at other times thread 2 never comes out of pop() (the block parameter is true) though the queue isn't empty. I understand there are other implementations available, but I'd like to try to fix this code, if needed. Anyone see any issues? The constructor has the appropriate initializations: Queue() { pthread_mutex_init( &mMutex, NULL ); pthread_cond_init( &mCondition, NULL ); } and the destructor, the corresponding 'destroy' calls.

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  • Problem in thread pool implementation(C#3.0)

    - by Newbie
    Hi Experts, I have done the below thread pool program but the problem is that the WaitCallBackMethod(here ThreadPoolCallback) is getting called 2 times(which ideally should be called 1ce). what is the misktake I am making? public class Calculation { #region Private variable declaration ManualResetEvent[] factorManualResetEvent = null; #endregion public void Compute() { factorManualResetEvent = new ManualResetEvent[2]; for (int i = 0; i < 2; i++){ factorManualResetEvent[i] = new ManualResetEvent(false); ThreadPool.QueueUserWorkItem(ThreadPoolCallback, i);} //Wait for all the threads to complete WaitHandle.WaitAll(factorManualResetEvent); //Proceed with the next task(s) NEXT_TASK_TO_BE_EXECUTED(); } #region Private Methods // Wrapper method for use with thread pool. public void ThreadPoolCallback(Object threadContext) { int threadIndex = (int)threadContext; Method1(); Method2(); factorManualResetEvent[threadIndex].Set(); } private void Method1 () { //Code of method 1} private void Method2 () { //Code of method 2 } #endregion } I am using C#3.0 Thanks

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  • Why doesn't PHP's oci_connect return false?

    - by absolethe
    I have a situation in which we have two production databases that synchronize with one other. Server One is considered the primary. Sometimes due to maintenance or a disaster Server Two will become primary. In some of our code that means we have to manually go in and edit the server name for database connections. I find this annoying, so the last thing I wrote I put the server information for both and set up a loop. If oci_connect failed on the Server One 3 times it would move on to Server Two. If Server Two failed 3 times it would notify the user a connection couldn't be made. This has worked fine most times we've had the situation of switching the servers. Yesterday, for example, it worked fine. Today it didn't. It just sat and spun endlessly. No error in the PHP error log. No failure to move on from. No error output to the screen. Nothing for 5 minutes. So then I had to manually edit the stupid config file. I asked what could possibly be different and I was told "yesterday the database was down, but not the server. today the server is down." Okay...? But I don't see a distinction. I would expect oci_connect to return false if it can't establish any sort of communication with the server. I'd expect it to timeout and error. Not just pass it on when it receives an error code from the server. What if there's a network problem, for example? Is this a bug in oci_connect or is there a possibility that something in our PHP configuration gives oci_connect a crazily long timeout? If it is a sort of "bug" is there some way I can check to see if the server is up first? Like a ping? (Of course when I did a ping through the command prompt I got a response from Server One and then was told, "it's back now" although I am skeptical about the timing on that.) Anyway, if anyone could shed some light on why oci_connect might run endlessly without failing and how to keep it from doing so I'd be grateful. -- Edit: My code looks like the examples on PHP.net only in some loops. $count = count($servers); for($i = 0; $i < $count; $i++){ if((!isset($connection)) || ($connection == false)){ // Attempt to connect to the oracle database $connection = @oci_connect($servers[$i]["user"], $servers[$i]["pass"], $servers[$i]["conid"]) or ($conn_error = oracle_error()); // Try again if there was a failure if(($connection == false) || (isset($con_error))){ // Three (two more) tries per alternative for($j = $st; $j < $fn; $j++){ // Try again to connect $connection = @oci_connect($servers[$i]["user"], $servers[$i]["pass"], $servers[$i]["conid"]) or ($conn_error = oracle_error()); } // for($j = 2; $j < 4; $j++) } // if($connection == false) } // if(!isset($connection) || ($connection == false)) } // for($i = 0; $i < $count; $i++)

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  • No Hibernate Session bound to thread exception

    - by Benchik
    I have Hibernate 3.6.0.Final and Spring 3.0.0.RELEASE I get "No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here" If I add the thread specification back in, I get "saveOrUpdate is not valid without active transaction" Any ideas? The spring-config.xml: <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"> <property name="driverClassName" value="org.hsqldb.jdbcDriver"/> <property name="url" value="jdbc:hsqldb:mem:jsf2demo"/> <property name="username" value="sa"/> <property name="password" value=""/> </bean> <bean id="sampleSessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean"> <property name="dataSource" ref="sampleDataSource"/> <property name="annotatedClasses"> <list> <value>com.maxheapsize.jsf2demo.Book</value> </list> </property> <property name="hibernateProperties"> <props> <!-- prop key="hibernate.connection.pool_size">0</prop--> <prop key="hibernate.show_sql">true</prop> <prop key="hibernate.dialect">org.hibernate.dialect.HSQLDialect</prop> <!-- prop key="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</prop> <prop key="hibernate.current_session_context_class">thread</prop--> <prop key="hibernate.hbm2ddl.auto">create</prop> </props> </property> </bean> <bean id="sampleDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName"> <value>org.hsqldb.jdbcDriver</value> </property> <property name="url"> <value> jdbc:hsqldb:file:/spring/db/springdb;SHUTDOWN=true </value> </property> <property name="username" value="sa"/> <property name="password" value=""/> </bean> <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager"> <property name="sessionFactory" ref="sampleSessionFactory"/> </bean> <bean id="daoTxTemplate" abstract="true" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean"> <property name="transactionManager" ref="transactionManager"/> <property name="transactionAttributes"> <props> <prop key="create*"> PROPAGATION_REQUIRED,ISOLATION_READ_COMMITTED </prop> <prop key="get*"> PROPAGATION_REQUIRED,ISOLATION_READ_COMMITTED </prop> </props> </property> </bean> <bean name="openSessionInViewInterceptor" class="org.springframework.orm.hibernate3.support.OpenSessionInViewInterceptor"> <property name="sessionFactory" ref="sampleSessionFactory"/> <property name="singleSession" value="true"/> </bean> <bean id="nameDao" parent="daoTxTemplate"> <property name="target"> <bean class="com.maxheapsize.dao.NameDao"> <property name="sessionFactory" ref="sampleSessionFactory"/> </bean> </property> </bean> and the DAO: public class NameDao { private SessionFactory sessionFactory; public void setSessionFactory(SessionFactory sessionFactory) { this.sessionFactory = sessionFactory; } public SessionFactory getSessionFactory() { return sessionFactory; } @Transactional @SuppressWarnings("unchecked") public List<Name> getAll() { Session session = this.sessionFactory.getCurrentSession(); List<Name> names = (List<Name>)session.createQuery("from Name").list(); return names; } //@Transactional(propagation= Propagation.REQUIRED, readOnly=false) @Transactional public void save(Name name){ Session session = this.sessionFactory.getCurrentSession(); session.saveOrUpdate(name); session.flush(); } }

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  • Simple Android Binary Text Clock

    - by Hristo
    Hello, I want to create a simple android binary clock but my application crashes. I use 6 textview fields: 3 for the decimal and 3 for the binary representation of the current time (HH:mm:ss). Here's the code: import java.text.SimpleDateFormat; import java.util.Calendar; import android.app.Activity; import android.os.Bundle; import android.widget.TextView; public class Binary extends Activity implements Runnable { Thread runner; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); if (runner == null) { //start the song runner = new Thread(this); runner.start(); } } @Override public void run() { TextView hours_dec = (TextView) findViewById(R.id.hours_dec); TextView mins_dec = (TextView) findViewById(R.id.mins_dec); TextView secs_dec = (TextView) findViewById(R.id.secs_dec); TextView hours_bin = (TextView) findViewById(R.id.hours_bin); TextView mins_bin = (TextView) findViewById(R.id.mins_bin); TextView secs_bin = (TextView) findViewById(R.id.secs_bin); SimpleDateFormat hours_sdf = new SimpleDateFormat("HH"); SimpleDateFormat mins_sdf = new SimpleDateFormat("mm"); SimpleDateFormat secs_sdf = new SimpleDateFormat("ss"); Calendar cal = Calendar.getInstance(); while (runner != null) { WaitAMoment(); cal.getTime(); hours_dec.setText(hours_sdf.format(cal.getTime())); mins_dec.setText(mins_sdf.format(cal.getTime())); secs_dec.setText(secs_sdf.format(cal.getTime())); hours_bin.setText(String.valueOf(Integer.toBinaryString(Integer.parseInt((String) hours_dec.getText())))); mins_bin.setText(String.valueOf(Integer.toBinaryString(Integer.parseInt((String) mins_dec.getText())))); secs_bin.setText(String.valueOf(Integer.toBinaryString(Integer.parseInt((String) secs_dec.getText())))); } } protected void WaitAMoment() { try { Thread.sleep(100); } catch (InterruptedException e) { }; } }`

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  • How to make Stack.Pop threadsafe

    - by user260197
    I am using the BlockingQueue code posted in this question, but realized I needed to use a Stack instead of a Queue given how my program runs. I converted it to use a Stack and renamed the class as needed. For performance I removed locking in Push, since my producer code is single threaded. My problem is how can thread working on the (now) thread safe Stack know when it is empty. Even if I add another thread safe wrapper around Count that locks on the underlying collection like Push and Pop do, I still run into the race condition that access Count and then Pop are not atomic. Possible solutions as I see them (which is preferred and am I missing any that would work better?): Consumer threads catch the InvalidOperationException thrown by Pop(). Pop() return a nullptr when _stack-Count == 0, however C++-CLI does not have the default() operator ala C#. Pop() returns a boolean and uses an output parameter to return the popped element. Here is the code I am using right now: generic <typename T> public ref class ThreadSafeStack { public: ThreadSafeStack() { _stack = gcnew Collections::Generic::Stack<T>(); } public: void Push(T element) { _stack->Push(element); } T Pop(void) { System::Threading::Monitor::Enter(_stack); try { return _stack->Pop(); } finally { System::Threading::Monitor::Exit(_stack); } } public: property int Count { int get(void) { System::Threading::Monitor::Enter(_stack); try { return _stack->Count; } finally { System::Threading::Monitor::Exit(_stack); } } } private: Collections::Generic::Stack<T> ^_stack; };

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  • proper use of volatile keyword

    - by luke
    I think i have a pretty good idea about the volatile keyword in java, but i'm thinking about re-factoring some code and i thought it would be a good idea to use it. i have a class that is basically working as a DB Cache. it holds a bunch of objects that it has read from a database, serves requests for those objects, and then occasionally refreshes the database (based on a timeout). Heres the skeleton public class Cache { private HashMap mappings =....; private long last_update_time; private void loadMappingsFromDB() { //.... } private void checkLoad() { if(System.currentTimeMillis() - last_update_time > TIMEOUT) loadMappingsFromDB(); } public Data get(ID id) { checkLoad(); //.. look it up } } So the concern is that loadMappingsFromDB could be a high latency operation and thats not acceptable, So initially i thought that i could spin up a thread on cache startup and then just have it sleep and then update the cache in the background. But then i would need to synchronize my class (or the map). and then i would just be trading an occasional big pause for making every cache access slower. Then i thought why not use volatile i could define the map reference as volatile private volatile HashMap mappings =....; and then in get (or anywhere else that uses the mappings variable) i would just make a local copy of the reference: public Data get(ID id) { HashMap local = mappings; //.. look it up using local } and then the background thread would just load into a temp table and then swap the references in the class HashMap tmp; //load tmp from DB mappings = tmp;//swap variables forcing write barrier Does this approach make sense? and is it actually thread-safe?

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  • Reading same file from multiple threads in C#

    - by Gustavo Rubio
    Hi. I was googling for some advise about this and I found some links. The most obvious was this one but in the end what im wondering is how well my code is implemented. I have basically two classes. One is the Converter and the other is ConverterThread I create an instance of this Converter class that has a property ThreadNumber that tells me how many threads should be run at the same time (this is read from user) since this application will be used on multi-cpu systems (physically, like 8 cpu) so it is suppossed that this will speed up the import The Converter instance reads a file that can range from 100mb to 800mb and each line of this file is a tab-delimitted value record that is imported to another destination like a database. The ConverterThread class simply runs inside the thread (new Thread(ConverterThread.StartThread)) and has event notification so when its work is done it can notify the Converter class and then I can sum up the progress for all these threads and notify the user (in the GUI for example) about how many of these records have been imported and how many bytes have been read. It seems, however that I'm having some trouble because I get random errors about the file not being able to be read or that the sum of the progress (percentage) went above 100% which is not possible and I think that happens because threads are not being well managed and probably the information returned by the event is malformed (since it "travels" from one thread to another) Do you have any advise on better practices of implementation of threads so I can accomplish this? Thanks in advance.

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  • Apply [ThreadStatic] attribute to a method in external assembly

    - by Sen Jacob
    Can I use an external assembly's static method like [ThreadStatic] method? Here is my situation. The assembly class (which I do not have access to its source) has this structure public class RegistrationManager() { private RegistrationManager() {} public static void RegisterConfiguration(int ID) {} public static object DoWork() {} public static void UnregisterConfiguration(int ID) {} } Once registered, I cannot call the DoWork() with a different ID without unregistering the previously registered one. Actually I want to call the DoWork() method with different IDs simultaneously with multi-threading. If the RegisterConfiguration(int ID) method was [ThreadStatic], I could have call it in different threads without problems with calls, right? So, can I apply the [ThreadStatic] attribute to this method or is there any other way I can call the two static methods same time without waiting for other thread to unregister it? If I check it like the following, it should work. for(int i=0; i < 10; i++) { new Thread(new ThreadStart(() => Checker(i))).Start(); } public string Checker(int i) { public static void RegisterConfiguration(i); // Now i cannot register second time public static object DoWork(i); Thread.Sleep(5000); // DoWork() may take a little while to complete before unregistered public static void UnregisterConfiguration(i); }

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  • Cannot make a static reference to the non-static type MyRunnable

    - by kaiwii ho
    Here is the whole code : import java.util.ArrayList; public class Test{ ThreadLocal<ArrayList<E>>arraylist=new ThreadLocal<ArrayList<E>>(){ @Override protected ArrayList<E> initialValue() { // TODO Auto-generated method stub //return super.initialValue(); ArrayList<E>arraylist=new ArrayList<E>(); for(int i=0;i<=20;i++) arraylist.add((E) new Integer(i)); return arraylist; } }; class MyRunnable implements Runnable{ private Test mytest; public MyRunnable(Test test){ mytest=test; // TODO Auto-generated constructor stub } @Override public void run() { System.out.println("before"+mytest.arraylist.toString()); ArrayList<E>myarraylist=(ArrayList<E>) mytest.arraylist.get(); myarraylist.add((E) new Double(Math.random())); mytest.arraylist.set(myarraylist); System.out.println("after"+mytest.arraylist.toString()); } // TODO Auto-generated method stub } public static void main(String[] args){ Test test=new Test<Double>(); System.out.println(test.arraylist.toString()); new Thread(new MyRunnable(test)).start(); new Thread(new MyRunnable(test)).start(); System.out.println(arraylist.toString()); } } my questions are: 1\ why the new Thread(new MyRunnable(test)).start(); cause the error: Cannot make a static reference to the non-static type MyRunnable ? 2\ what is the static reference refer to right here? thx in advanced

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  • Multiple locking task (threading)

    - by Archeg
    I need to implement the class that should perform locking mechanism in our framework. We have several threads and they are numbered 0,1,2,3.... We have a static class called ResourceHandler, that should lock these threads on given objects. The requirement is that n Lock() invokes should be realeased by m Release() invokes, where n = [0..] and m = [0..]. So no matter how many locks was performed on single object, only one Release call is enough to unlock all. Even further if o object is not locked, Release call should perform nothing. Also we need to know what objects are locked on what threads. I have this implementation: public class ResourceHandler { private readonly Dictionary<int, List<object>> _locks = new Dictionary<int, List<object>>(); public static ResourceHandler Instance {/* Singleton */} public virtual void Lock(int threadNumber, object obj) { Monitor.Enter(obj); if (!_locks.ContainsKey(threadNumber)) {_locks.Add(new List<object>());} _locks[threadNumber].Add(obj); } public virtual void Release(int threadNumber, object obj) { // Check whether we have threadN in _lock and skip if not var count = _locks[threadNumber].Count(x => x == obj); _locks[threadNumber].RemoveAll(x => x == obj); for (int i=0; i<count; i++) { Monitor.Exit(obj); } } // ..... } Actually what I am worried here about is thread-safety. I'm actually not sure, is it thread-safe or not, and it's a real pain to fix that. Am I doing the task correctly and how can I ensure that this is thread-safe?

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  • C# Socket.BeginSend AsyncCallback behavior (timeout?)

    - by mdarsigny
    Hi guys, Here is a scenario with asynchronous sockets that I dont't quite understand... I have 2 Tcp sockets, a client socket & a server socket. My server socket is bound & listening on a port. My client sockets connect to the server socket (using BeginConnect / EndConnect). I then send a message to the server using BeginSend(). On the server side, I don't do a Receive() or BeginReceive(). What happens is that my AsyncCallback specified for my BeginSend call gets invoked & its IAsyncResult tells me that it completed & the call to Socket.EndSend() does not raise any exception... Is there something that I don't get or shouldn't my AsyncCallback be called only if the BeginSend call actually sends something to the server (ie.: callback called after the server has received all bytes)? If there was no receive done on the server, shouldn't my callback be called after the sendtimeout expires and my call to Socket.EndSend then would raise an exception? Thanks

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  • Silverlight Confirm Dialog to Pause Thread

    - by AlishahNovin
    I'm trying to do a confirmation dialog using Silverlight's ChildWindow object. Ideally, I'd like it to work like MessageBox.Show(), where the entire application halts until an input is received from the user. For example: for(int i=0;i<5;i++) { if (i==3 && MessageBox.Show("Exit early?", "Iterator", MessageBoxButton.OKCancel) == MessageBoxResult.OK) { break; } } Would stop the iteration at 3 if the user hits OK... However, if I were to do something along the lines: ChildWindow confirm = new ChildWindow(); confirm.Title = "Iterator"; confirm.HasCloseButton = false; Grid container = new Grid(); Button closeBtn = new Button(); closeBtn.Content = "Exit early"; closeBtn.Click += delegate { confirm.DialogResult = true; confirm.Close(); }; container.Children.Add(closeBtn); Button continueBtn = new Button(); continueBtn.Content = "Continue!"; continueBtn.Click += delegate { confirm.DialogResult = false; confirm.Close(); }; container.Children.Add(continueBtn); confirm.Content = container; for(int i=0;i<5;i++) { if (i==3) { confirm.Show(); if (confirm.DialogResult.HasResult && (bool)confirm.DialogResult) { break; } } } This clearly would not work, as the thread isn't halted... confirm.DialogResult.HasResult would be false, and the loop would continue past 3. I'm just wondering, how I could go about this properly. Silverlight is single-threaded, so I can't just put the thread to sleep and then wake it up when I'm ready, so I'm just wondering if there's anything else that people could recommend? I've considered reversing the logic - ie, passing the actions I want to occur to the Yes/No events, but in my specific case this wouldn't quite work. Thanks in advance!

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  • QNetworkAccessManager timeout.

    - by Umesha MS
    Hi, Presently I am working on an application which sends and receives file from remote server. To do network operation I am using QNetworkAccessManager. To upload a file I am using QNetworkAccessManager::put() and to download I am using QNetworkAccessManager::get() functions. While uploading a file I will initialize a timer with time out of 15 sec. if I upload a small file it will complete it within the time out period. But if I try to upload a file which is very large in size get time out. So how to decide time out for uploading of large file. Same in case of downloading of a large file. I get file in chunk by chunk in readyread() signal. Here also if I download a large file I get time out. So how to decide time out for uploading of large file.

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  • Silverlight Async Timeout Error

    - by Nath
    Calling through to my Silverlight Enabled WCF-Service in my silverlight application, occasionally users get timeouts. Whats the easiest way to boost the time allowed by the service client for a response? The exact exception thrown is: System.TimeoutException: [HttpRequestTimedOutWithoutDetail] Thanks

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  • WCF Reliable Session Timeout

    - by RemotecUk
    Hi, when do reliable sessions time out? My session class is defined as follows: [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession, ConcurrencyMode = ConcurrencyMode.Multiple)] and in my app.config... <bindings> <netTcpBinding> <binding name="FTS_netTcpBinding"> <reliableSession enabled="true" inactivityTimeout="00:00:30"/> </binding> </netTcpBinding> </bindings> I have put a timer in the constructor of my session class that simply outputs a count (1..2..3...) to the console for every second the session is active. I have tested it so far by faulting my channel. I would have imagined that the session class would have died after ~30 seconds (as specified in my inactivityTimeout parameter) and hence the timer would have died. However it was still going after a minute. Each session on my app will have significant resources so I need to make sure that they are cleaned up when something goes wrong. Thanks.

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