[Java] 別スレッドからのtrigger()をポーリングして待ち非同期に処理を実行

TriggerPolling.java

public class TriggerPolling implements Runnable {
	private final Runnable handler;
	private final int interval;
	private final AtomicBoolean triggered = new AtomicBoolean();
	private volatile boolean shutdown = false;

	/**
	 * @param handler trigger()されたら実行される処理
	 * @param interval ポーリング間隔(ミリ秒)
	 */
	public TriggerPolling(Runnable handler, int interval) {
		this.handler = handler;
		this.interval = interval;
	}

	/**
	 * 処理実行のフラグをON.
	 */
	public void trigger() {
		triggered.set(true);
	}

	/**
	 * スレッド終了.
	 */
	public void shutdown() {
		shutdown = true;
	}

	@Override
	public void run() {
		try {
			poll();
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}

	private void poll() throws InterruptedException {
		while (!shutdown) {
			if (triggered.getAndSet(false)) {
				handler.run();
			} else {
				Thread.sleep(interval);
			}
		}
	}

	/**
	 * test.
	 */
	public static void main(String[] args) throws InterruptedException {
		TriggerPolling target = new TriggerPolling(new Runnable() {
			public void run() {
				System.out.print(".");
			}
		}, 50);
		new Thread(target).start();
		for (int i = 0; i < 50; i++) {
			target.trigger();
			Thread.sleep(i * 10);
		}
		target.shutdown();
	}
}