Question

I am working with threads, and decided to use the most modern API (java.util.concurrent package).

Here’s what I want to do (pseudocode):

//List of threads

private ScheduledExecutorService checkIns = Executors.newScheduledThreadPool(10);
//Runnable class

private class TestThread implements Runnable{
  private int index = 0;
  private long startTime = 0;
  private long timeToExecute = 3000000;
   public TestThread(int index){
      this.index = index;
   }

   public void run(){
      if(startTime == 0)
        startTime = System.currentTimeMillis();
      else if(startTime > (startTime+timeToExecute))
           //End Thread
      System.out.println("Execute thread with index->"+index);
    }
}

//Cycle to create 3 threads
for(int i=0;i< 3; i++)
    checkIns.scheduleWithFixedDelay(new TestThread(i+1),1, 3, TimeUnit.SECONDS);

I want to run a task on a certain date and repeat it until a certain amount of time. After the time has elapsed, the task ends. My only question is how to end with the thread?

Answer 1

Well, you can throw an exception from the task when it should no longer execute, but that’s fairly brutal Alternatives:

• Schedule the task once, making the task aware of the scheduler, so it can reschedule itself when it’s finished its current iteration – but just return immediately if it’s after its final time.
• Use something like Quartz Scheduler which is more designed for this sort of thing.

Of course the first version can be encapsulated into a somewhat more pleasant form – you could create a “SchedulingRunnable” which knows when it’s meant to run a subtask (provided to it) and how long for.