implementing debounce in Java

Question

For some code I\'m writing I could use a nice general implementation of debounce in Java.

public interface Callback {
  public void call(Object          


        

Answer 1

The following implementation works on Handler based threads (e.g. the main UI thread, or in an IntentService). It expects only to be called from the thread on which it is created, and it will also run it's action on this thread.

public class Debouncer
{
    private CountDownTimer debounceTimer;
    private Runnable pendingRunnable;

    public Debouncer() {

    }

    public void debounce(Runnable runnable, long delayMs) {
        pendingRunnable = runnable;
        cancelTimer();
        startTimer(delayMs);
    }

    public void cancel() {
        cancelTimer();
        pendingRunnable = null;
    }

    private void startTimer(final long updateIntervalMs) {

        if (updateIntervalMs > 0) {

            // Debounce timer
            debounceTimer = new CountDownTimer(updateIntervalMs, updateIntervalMs) {

                @Override
                public void onTick(long millisUntilFinished) {
                    // Do nothing
                }

                @Override
                public void onFinish() {
                    execute();
                }
            };
            debounceTimer.start();
        }
        else {

            // Do immediately
            execute();
        }
    }

    private void cancelTimer() {
        if (debounceTimer != null) {
            debounceTimer.cancel();
            debounceTimer = null;
        }
    }

    private void execute() {
        if (pendingRunnable != null) {
            pendingRunnable.run();
            pendingRunnable = null;
        }
    }
}