cyclicbarrier

从JDK 1.5之后，在java.util.concurrent包下引入了好多的处理多线程的工具类，本文首先会介绍CyclicBarrier辅助工具类，其次将用CyclicBarrier工具类来完成一个实例，最后将给出CyclicBarrier和CountDownLatch的几点比较。 之前关于CountDownLatch的博文，请参考 使用CountDownLatch协调子线程 以前在<<编写高质量代码－改善Java程序的151个建议>>一书中看到有一节的标题是“ CyclicBarrier让多线程齐步走 ”，觉得这标题挺不错的，所以在写这篇博文的时候也采用了这个名字。 CyclicBarrier工具类介绍 CyclicBarrier描述 CyclicBarrier 是一个同步辅助工具类， 它允许一组线程相互等待，直到到达一个公共的栏栅点。 CyclicBarrier对于那些包含一组固定大小线程，并且这些线程必须不时地相互等待的程序非常有用 。之所以将其称之为循环的Barrier是因为该Barrier在等待的线程释放之后可以重用。 CyclicBarrier 支持一个可选的 Runnable 命令，在一组线程中的最后一个线程到达之后（但在释放所有线程之前），该命令只在每个屏障点运行一次。若在继续所有参与线程之前更新共享状态，此屏障操作 很有用。

I have wrote code to understand CyclicBarrier. My application emulates election. Each rounds selects candidate with small votes and this candidate eliminates from the race for victory. source: class ElectoralCommission { public volatile boolean hasWinner; public volatile String winner; private List<String> candidates; private Map<String, Integer> results = new ConcurrentHashMap<>(); ElectoralCommission(List<String> candidates) { this.candidates = candidates; } public void acceptVote(int index) { Integer currentResult = results.get(candidates.get(index)); results.put(candidates.get(index),

I need something which is directly equivalent to CountDownLatch , but is resettable (remaining thread-safe!). I can't use classic synchronisation constructs as they simply don't work in this situation (complex locking issues). At the moment, I'm creating many CountDownLatch objects, each replacing the previous one. I believe this is doing in the young generation in the GC (due to the sheer number of objects). You can see the code which uses the latches below (it's part of the java.net mock for a ns-3 network simulator interface). Some ideas might be to try CyclicBarrier (JDK5+) or Phaser (JDK7

Which Java synchronization construct is likely to provide the best performance for a concurrent, iterative processing scenario with a fixed number of threads like the one outlined below? After experimenting on my own for a while (using ExecutorService and CyclicBarrier) and being somewhat surprised by the results, I would be grateful for some expert advice and maybe some new ideas. Existing questions here do not seem to focus primarily on performance, hence this new one. Thanks in advance! The core of the app is a simple iterative data processing algorithm, parallelized to the spread the

I was reading through the java.util.concurrent API , and found that CountDownLatch : A synchronization aid that allows one or more threads to wait until a set of operations being performed in other threads completes. CyclicBarrier : A synchronization aid that allows a set of threads to all wait for each other to reach a common barrier point. To me both seems equal, but I am sure there is much more to it. For example, in CoundownLatch, the countdown value could not be reset, that can happen in the case of CyclicBarrier . Is there any other difference between the two? What are the use cases