超时后中断任务的ExecutorService
超时后中断任务的ExecutorService
提问于 2010-05-03 22:10:37
我正在寻找一个可以提供超时的ExecutorService实现。如果提交到ExecutorService的任务的运行时间超过超时，则会中断这些任务。实现这样一个野兽并不是一项困难的任务，但我想知道是否有人知道现有的实现。
这是我根据下面的一些讨论得出的结论。有什么意见吗？
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();
}
}
}回答 9
Stack Overflow用户
回答已采纳
发布于 2010-05-03 23:12:59
为此，您可以使用ScheduledExecutorService。首先，您只需提交一次，即可立即开始并保留所创建的未来。在此之后，您可以提交一个新任务，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);这将执行您的处理程序(主要功能将被中断) 10秒，然后将取消(即中断)该特定任务。
Stack Overflow用户
发布于 2012-10-12 00:14:14
不幸的是，解决方案是有缺陷的。this question中也报道了ScheduledThreadPoolExecutor有一种bug :取消提交的任务不会完全释放与该任务关联的内存资源；只有在任务到期时才会释放这些资源。
因此，如果您创建了一个具有相当长的过期时间(典型用法)的TimeoutThreadPoolExecutor，并且提交任务的速度足够快，那么您最终会填满内存-即使这些任务实际上已成功完成。
您可以在以下(非常粗糙的)测试程序中看到问题：
public static void main(String[] args) throws InterruptedException {
ExecutorService service = new TimeoutThreadPoolExecutor(1, 1, 10, TimeUnit.SECONDS,
new LinkedBlockingQueue<Runnable>(), 10, TimeUnit.MINUTES);
//ExecutorService service = Executors.newFixedThreadPool(1);
try {
final AtomicInteger counter = new AtomicInteger();
for (long i = 0; i < 10000000; i++) {
service.submit(new Runnable() {
@Override
public void run() {
counter.incrementAndGet();
}
});
if (i % 10000 == 0) {
System.out.println(i + "/" + counter.get());
while (i > counter.get()) {
Thread.sleep(10);
}
}
}
} finally {
service.shutdown();
}
}程序会耗尽可用内存，尽管它会等待衍生的Runnable完成。
我对此考虑了一段时间，但不幸的是我想不出一个好的解决方案。
编辑:我发现这个问题被报告为JDK bug 6602600，而且最近似乎已经修复了。
Stack Overflow用户
发布于 2010-05-03 22:46:55
将任务包装在FutureTask中，您可以为FutureTask指定超时。请看我对这个问题的回答中的示例，
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/2758612
复制相关文章
相似问题