From ExtremeProgrammingChallengeFourteenTheBug

----

import java.util.*;

public class BoundedBuffer {

    	synchronized
	void put(Object x) throws InterruptedException {		
	    while ( occupied == buffer.length ) {
		wait();
	    }
	    /***/ TestBB.doSleep();
	    notify();
	    /***/ TestBB.doSleep();
	    ++occupied;
	    putAt %= buffer.length;
	    buffer[putAt++] = x;
	}
	
	synchronized
	Object take() throws InterruptedException {
	    while ( occupied == 0 ) {
		wait();
	    }
	    /***/ TestBB.doSleep();
	    notify();
	    --occupied;
	    takeAt %= buffer.length;
	    return buffer[takeAt++];
	}

	private Object[] buffer = new Object[1];
	private int putAt, takeAt, occupied;

}

class TestBB extends Thread {

	private static final int 		slow = 10;

	private static int[]			c1sleeps = {0,slow};
	private static int[]			c2sleeps = {0,0};
	private static int[]			p1sleeps = {0,slow*2,slow*2};
	private static int[]			p2sleeps = {0,0,0};

	private static BoundedBuffer		theBB = new BoundedBuffer();
	private static Hashtable		threads = new Hashtable();

	public static void main(String[] args) throws Throwable {
	    int pass = 0;
	    int fail = 0;
	    for (int i=0; i< 50; i++) {
		if (doTest()) {
		    System.out.println("Fail.");
		    fail++;
		} else {
		    System.out.println("Pass.");
		    pass++;
		}
	    }
	    System.out.println("Slow is "+slow+", false pass:"+pass+", fail:"+fail);
	}

	public static boolean doTest() throws Throwable {
	    theBB = new BoundedBuffer();
	    c1sleeps[0] = 0;
	    c2sleeps[0] = 0;
	    p1sleeps[0] = 0;
	    p2sleeps[0] = 0;
	    TestBB c1 = new TestBB("c1",c1sleeps) {
			    public void run() {
				    try {
					    theBB.take();
				    }
				    catch (InterruptedException ie) {}
			    }
	    };
	    TestBB c2 = new TestBB("c2",c2sleeps) {
			    public void run() {
				    try {
					theBB.take();
				    }
				    catch (InterruptedException ie) {}
			    }
	    };
	    TestBB p1 = new TestBB("p1",p1sleeps) {
			    public void run() {
				    try {
					    theBB.put("A");
				    }
				    catch (InterruptedException ie) {}
			    }
	    };
	    TestBB p2 = new TestBB("p2",p2sleeps) {
			    public void run() {
				    try {
					    theBB.put("B");
				    }
				    catch (InterruptedException ie) {}
			    }
	    };
	    c1.start();
	    Thread.sleep(slow);
	    c2.start();
	    Thread.sleep(slow);
	    p1.start();
	    Thread.sleep(slow);
	    p2.start();
	    Thread.sleep(300+(slow*10));
	    if (p2.isAlive()) {
		    System.out.println("Liveness problem detected.");
		    return true;
	    }
	    else return false;
	}

	public TestBB(String name,int[] sleeps) {
    		super(name);
		threads.put(this,sleeps);
	}

	public static void doSleep() {
		int[] sleepsForThread = (int[])threads.get(Thread.currentThread());
		if (sleepsForThread != null) {
			int current = 1+(sleepsForThread[0] % (sleepsForThread.length-1));
			sleepsForThread[0]++;
			try {
				Thread.sleep(sleepsForThread[current]);
			}
			catch(InterruptedException ie) {}
		}
	}
}