Java ExecutorService pause/resume a specific thread

Question

Is there a way to use ExecutorService to pause/resume a specific thread?

private static ExecutorService threadpool = Executors.newFixedThreadPool(5);
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Answer 1

Suggestion: Similarly to/instead of the flags you're using, create a semaphore with 1 permit (new Semaphore(1)) for each task you need to pause/unpause. At the beginning of the task's working cycle put a code like this:

semaphore.acquire();
semaphore.release();

This causes the task to acquire a semaphore permit and immediately release it. Now if you want to pause the thread (a button is pressed, for example), call semaphore.acquire() from another thread. Since the semaphore has 0 permits now, your working thread will pause at the beginning of the next cycle and wait until you call semaphore.release() from the other thread.

(The acquire() method throws InterruptedException, if your working thread gets interrupted while waiting. There is another method acquireUninterruptibly(), which also tries to acquire a permit, but doesn't get interrupted.)