JoinableTask.java

package com.nvarghese.beowulf.common.cobra.util;

/**
 * A task that can be used in a thread or thread pool. The caller can wait for
 * the task to finish by joining it.
 */
public abstract class JoinableTask implements SimpleThreadPoolTask {

	private boolean done = false;

	public final void run() {

		try {
			this.execute();
		} finally {
			synchronized (this) {
				this.done = true;
				this.notifyAll();
			}
		}
	}

	public final void forceDone() {

		synchronized (this) {
			this.done = true;
			this.notifyAll();
		}
	}

	public void join() throws InterruptedException {

		synchronized (this) {
			while (!this.done) {
				this.wait();
			}
		}
	}

	public void cancel() {

		this.forceDone();
	}

	protected abstract void execute();
}