How to reschedule a task using timer?

Question

Here is my problem, I am sending some message to a queue using JMS. The program has been written in such a way that there will be a message sent to the queue within 30 seconds from the time of the previous message sent. If there are no messages sent in the 30 seconds duration then the message is the last message and I should start consuming the messages from the queue.

My Initial thought is to create a timer with a task(Here receiving message form the queue), when a new message is created, the method is called and the task waits for 30sec. If the method is called again that means another message has come so the task has to be rescheduled.

This is the code I have written:

public void startTimer() {
    Timer t = new Timer();
    try {
        t.schedule(task, timeDelay);
    } catch (Exception e) {
        t.cancel();
        t = new Timer();
        t.schedule(task, timeDelay);
    }
}

I am trying to schedule a timer, if there is an existing task scheduled to it then I am canceling that timer, creating a new timer and scheduling a new task.

I am getting error message as Task already scheduled or cancelled.

Any idea for improvement or suggestions or solutions are most welcome.

Answer 1

You cannot use the same TimerTask in one or several Timer.

You need to create a new instance of the TimerTask to be executed:

t.cancel();
t = new Timer();
TimerTask newTask = new MyTimerTask();  // new instance
t.schedule(newTask, timeDelay);