ExecutorService that interrupts tasks after a timeout

Question

I'm looking for an ExecutorService implementation that can be provided with a timeout. Tasks that are submitted to the ExecutorService are interrupted if they take longer than the timeout to run. Implementing such a beast isn't such a difficult task, but I'm wondering if anybody knows of an existing implementation.

Here's what I came up with based on some of the discussion below. Any comments?

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();         }     } } 

Answer 1

You can use a ScheduledExecutorService for this. First you would submit it only once to begin immediately and retain the future that is created. After that you can submit a new task that would cancel the retained future after some period of time.

 ScheduledExecutorService executor = Executors.newScheduledThreadPool(2);   final Future handler = executor.submit(new Callable(){ ... });  executor.schedule(new Runnable(){      public void run(){          handler.cancel();      }        }, 10000, TimeUnit.MILLISECONDS); 

This will execute your handler (main functionality to be interrupted) for 10 seconds, then will cancel (i.e. interrupt) that specific task.

Answer 2

Wrap the task in FutureTask and you can specify timeout for the FutureTask. Look at the example in my answer to this question,

java native Process timeout