synchronization

问题 Is it possible to synchronize videos running in a WPF application across two or more computers? Synchronizing several videos running on the same machine seems to work well using the ParallelTimeline class and MediaTimelines for each video instance, but I haven’t figure out a way to do this across different computers, which if possible, would enable some incredible multi-screen installations. So to all those WPF gurus out there, what do you think? Could this work with WPF or do I need to fall

问题 I am not sure I understand Synchronized Lists in Java. Suppose I have the following: List<Integer> numbers = Collections.synchronizedList(new ArrayList<Integer>()); // Assumption: This is running on a separate thread public void add() { numbers.add(new Random().nextInt(100)); } // This is also running on a separate thread public void doSomething() { synchronized(numbers) { for (int i : numbers) {} } } Basically, will the add() be able to add numbers to the list if doSomething() is invoked?

问题 Does anyone know if iPhone (i.e. Cocoa Touch) lets you create custom properties? I've used it with the mac before (where it works beautifully) and would like to use this technology for an iPhone app that syncs with an app on the mac through the Address Book (using MobileMe). If I can't use custom properties, however, I'll have to abandon this strategy. For the mac, it's relatively easy: http://developer.apple.com/mac/library/documentation/UserExperience/ Conceptual/AddressBook/Tasks

问题 I'm wondering how SQLite implements it. Is it based on file-locking? Surely the entire DB isn't locked for every user that accesses it; that would be extremely inefficient. Is it based on multiple files or just one big file? Would be nice if someone could give a short overview of how synchronization and locking is done in sqlite, or, of course, provide a link to one. 回答1: Have a look at the SQL Lite FAQ and this on locking. Hope this helps. 来源： https://stackoverflow.com/questions/589675

问题 I am looking for a way to cache prepared statements in a servlet environment (specifically, Tomcat 5.5). This is meant to reduce the number of times that prepared statements are created, i.e. the number of times that connection.prepareStatement(sql) is called. My initial idea was to store PreparedStatement objects in the session, where the key (the attribute name) is the query itself. This can also be done lazily. However, someone alerted me to the fact that, depending on the JDBC driver

问题 I think I am missing something about correct behaviour of Monitor.Enter and Monitor.TryEnter . Here is a piece of code I wrote to separate the issue from the rest of the code: object lockObj = new object(); bool result = Monitor.TryEnter(lockObj); Console.Write(result); Result is always true . No surprises here. object lockObj = new object(); Monitor.Enter(lockObj); bool result = Monitor.TryEnter(lockObj); Console.Write(result); But this time it is also true . So is lockObj locked after

问题 I have a struct with some integers field, like struct s { int a; int b; int c; int max; }; struct s mystruct = {0, 0, 0, 0}; // Global var And then I have N threads that sometimes have to do things like ++ or -- on the first three fields, and sometimes have to read them and then update the max field. Do I have to use a mutex here? And if yes, is it needed only when reading/updating max or always? Why? If I just increment or decrement the first three fields, does it matter if a thread runs

问题 When creating a CUDA event, you can optionally turn on the cudaEventBlockingSync flag. But - what if the difference between creating an event with or without the flag? I read the fine manual; it just doesn't make sense to me. What is the "calling host thread", and what "blocks" when you don't use the flag? 4.6.2.7 cudaError_t cudaEventSynchronize(cudaEvent_t event) Blocks until the event has actually been recorded. ... Waiting for an event that was created with the cudaEventBlockingSync flag

问题 I am enhancing an existing algorithm that consists of multiple independent steps to use concurrent tasks. Each of the tasks will create multiple objects to hold its results. In the end, I would like to have a list of all the results to return from the controlling method. At the moment, my code looks something like that private final ExecutorService pool = ...; // A single task to be performed concurrently with other tasks. private class WorkHorse implements Callable<Void> { private final

问题 I'm reading about some android basic game techniques for learning purposes. I came across some code that synchronizes the access to the SurfaceHolder object used on the game loop thread, why is this necessary? Sample code found in sdk/samples/android-18/legacy/LunarLander , LunarView.LunarThread class: public void run() { while (mRun) { Canvas c = null; try { c = mSurfaceHolder.lockCanvas(null); synchronized (mSurfaceHolder) { if (mMode == STATE_RUNNING) updatePhysics(); synchronized