/*
 *  ========================================================================
 *  CubbyHole.java : Contains the shared contents which is stored by the Producer
 *  object and consumed by the Consumer object. In order to allow the Consumer
 *  object to consume the contents only once as soon as the Producer object
 *  stores the contents, the synchronized keyword is placed in the put and get methods.
 *  
 *  Adapted from : Campione M., Walrath K., Huml A., The Java Tutorial, 2000
 *  Modified by : Vasilios Lagakos                              March, 2001 
 *  =========================================================================
 */

public class CubbyHole {
    private int contents;		// shared data
    private boolean available = false;

/* Method used by the consumer to access the shared data */
    public synchronized int get() {	
        while (available == false) {
            try {
                wait();		// Consumer enters a wait state until notified by the Producer
            } catch (InterruptedException e) { }
        }
        available = false;
        notifyAll();		// Consumer notifies Producer that it can store new contents
        return contents;	
    }

/* Method used by the consumer to access (store) the shared data */
    public synchronized void put(int value) {
        while (available == true) {
            try {
                wait();		// Producer who wants to store contents enters 
				// a wait state until notified by the Consumer 
            } catch (InterruptedException e) { }
        }
        contents = value;
        available = true;
        notifyAll();		// Producer notifies Consumer to come out 
				// of the wait state and consume the contents
    }
}