Timeout.java

package book.example.async;

public class Timeout {
    private final long endTime;

    public Timeout(long duration) {
        this.endTime = System.currentTimeMillis() + duration;
    }

    public boolean hasTimedOut() {
        return timeRemaining() <= 0;
    }

    public void waitOn(Object lock) throws InterruptedException {
        long waitTime = timeRemaining();
        if (waitTime > 0) lock.wait(waitTime);
    }

    private long timeRemaining() {
        return endTime - System.currentTimeMillis();
    }
}