InterruptibleQueue.java

package ioio.lib.impl;

import java.util.Queue;
import java.util.concurrent.ArrayBlockingQueue;

public class InterruptibleQueue<T> {
    private Queue<T> queue_;

    public static class Nudged extends Throwable {
        private static final long serialVersionUID = -7943717843515344247L;
    }

    public InterruptibleQueue(int capacity) {
        assert capacity > 0;
        queue_ = new ArrayBlockingQueue<T>(capacity);
    }

    public synchronized void pushDiscardingOld(T element) {
        if (!queue_.offer(element)) {
            queue_.remove();
            queue_.offer(element);
        }
        notifyAll();
    }

    public synchronized T pull() throws Nudged, InterruptedException {
        if (queue_.isEmpty()) {
            wait();
        }
        if (queue_.isEmpty()) {
            throw new Nudged();
        }
        return queue_.remove();
    }

    public synchronized void nudge() {
        notifyAll();
    }
}