java.util.Timer - Example

Timer class in java gives capability to schedule tasks for future execution in a background thread.
Task can be schedule for one time execution or for multiple times after specified regular intervals.

Example
 We will use Timer class to maintain a count of tasks processed in last one minute, five minute and ten minutes. We will also use AtomicInteger

 import java.util.Timer;

import java.util.TimerTask;

import java.util.concurrent.atomic.AtomicInteger;

public class TimerTest extends Timer

{

    private final AtomicInteger oneMinuteCounter;

    private final AtomicInteger fiveMinuteCounter;

    private final AtomicInteger tenMinuteCounter;

    public static final long MILLIS_IN_MINUTE = 60000;

    private Timer taskManager = new Timer("taskManager");

    public TimerTest()

    {

        oneMinuteCounter = new AtomicInteger(0);

        fiveMinuteCounter = new AtomicInteger(0);

        tenMinuteCounter = new AtomicInteger(0);

    }

    protected static class Decrement extends TimerTask

    {

        private final AtomicInteger atomicInteger;

        public Decrement(AtomicInteger integer)

        {

            atomicInteger = integer;

        }

        @Override

        public void run()

        {

            atomicInteger.decrementAndGet();

        }

    }

    public void executeTask()

    {

        oneMinuteCounter.incrementAndGet();

        taskManager.schedule(new Decrement(oneMinuteCounter), MILLIS_IN_MINUTE);

        fiveMinuteCounter.incrementAndGet();

        taskManager.schedule(new Decrement(fiveMinuteCounter), 5 * MILLIS_IN_MINUTE);

        tenMinuteCounter.incrementAndGet();

        taskManager.schedule(new Decrement(tenMinuteCounter), 5 * MILLIS_IN_MINUTE);

    }

 

    public void printTaskExecution()

    {

        System.out.println(oneMinuteCounter.get());

        System.out.println(fiveMinuteCounter.get());

        System.out.println(oneMinuteCounter.get());

    }

    public static void main(String... args)

    {

        TimerTest timer = new TimerTest();

       for(int i=0; i <1000 ; i++)

           try
            {
                timer.executeTask();
                Thread.sleep(10000);
            }
            catch (InterruptedException e)
            {
                e.printStackTrace();
            }
        }
    }
}