How to wait for all threads to finish, using ExecutorService?
Basically on an ExecutorService you call shutdown() and then awaitTermination():
ExecutorService taskExecutor = Executors.newFixedThreadPool(4);while(...) { taskExecutor.execute(new MyTask());}taskExecutor.shutdown();try { taskExecutor.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);} catch (InterruptedException e) { ...}
Use a CountDownLatch:
CountDownLatch latch = new CountDownLatch(totalNumberOfTasks);ExecutorService taskExecutor = Executors.newFixedThreadPool(4);while(...) { taskExecutor.execute(new MyTask());}try { latch.await();} catch (InterruptedException E) { // handle}and within your task (enclose in try / finally)
latch.countDown();
ExecutorService.invokeAll() does it for you.
ExecutorService taskExecutor = Executors.newFixedThreadPool(4);List<Callable<?>> tasks; // your tasks// invokeAll() returns when all tasks are completeList<Future<?>> futures = taskExecutor.invokeAll(tasks);