我正在寻找可以提供超时的ExecutorService实现。如果提交到ExecutorService的任务花费的时间超过了超时时间,则这些任务将被中断。实现这样的野兽并不是一个困难的任务,但是我想知道是否有人知道现有的实现。
这是我根据以下一些讨论得出的。任何意见?
import java.util.List; import java.util.concurrent.*; public class TimeoutThreadPoolExecutor extends ThreadPoolExecutor { private final long timeout; private final TimeUnit timeoutUnit; private final ScheduledExecutorService timeoutExecutor = Executors.newSingleThreadScheduledExecutor(); private final ConcurrentMap<Runnable, ScheduledFuture> runningTasks = new ConcurrentHashMap<Runnable, ScheduledFuture>(); public TimeoutThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, long timeout, TimeUnit timeoutUnit) { super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue); this.timeout = timeout; this.timeoutUnit = timeoutUnit; } public TimeoutThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory, long timeout, TimeUnit timeoutUnit) { super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory); this.timeout = timeout; this.timeoutUnit = timeoutUnit; } public TimeoutThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, RejectedExecutionHandler handler, long timeout, TimeUnit timeoutUnit) { super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, handler); this.timeout = timeout; this.timeoutUnit = timeoutUnit; } public TimeoutThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory, RejectedExecutionHandler handler, long timeout, TimeUnit timeoutUnit) { super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory, handler); this.timeout = timeout; this.timeoutUnit = timeoutUnit; } @Override public void shutdown() { timeoutExecutor.shutdown(); super.shutdown(); } @Override public List<Runnable> shutdownNow() { timeoutExecutor.shutdownNow(); return super.shutdownNow(); } @Override protected void beforeExecute(Thread t, Runnable r) { if(timeout > 0) { final ScheduledFuture<?> scheduled = timeoutExecutor.schedule(new TimeoutTask(t), timeout, timeoutUnit); runningTasks.put(r, scheduled); } } @Override protected void afterExecute(Runnable r, Throwable t) { ScheduledFuture timeoutTask = runningTasks.remove(r); if(timeoutTask != null) { timeoutTask.cancel(false); } } class TimeoutTask implements Runnable { private final Thread thread; public TimeoutTask(Thread thread) { this.thread = thread; } @Override public void run() { thread.interrupt(); } } }
你可以为此使用ScheduledExecutorService。首先,你只提交一次即可立即开始,并保留创建的未来。之后,你可以提交新任务,该任务将在一段时间后取消保留的将来。
ScheduledExecutorService executor = Executors.newScheduledThreadPool(2); final Future handler = executor.submit(new Callable(){ ... }); executor.schedule(new Runnable(){ public void run(){ handler.cancel(); } }, 10000, TimeUnit.MILLISECONDS);
这将使你的处理程序(主要功能被中断)执行10秒钟,然后将取消(即中断)该特定任务。