package threadbook.ch08;

public class CubbyHole extends Object {

private Object slot;

public CubbyHole() {

slot = null; // null indicates empty

}

public synchronized void putIn(Object obj)

throws InterruptedException {

print("in putIn() - entering");

while ( slot != null ) {

print("in putIn() - occupied, about to wait()");

wait(); // wait while slot is occupied

print("in putIn() - notified, back from wait()");

}

slot = obj; // put object into slot

print("in putIn() - filled slot, about to notifyAll()");

notifyAll(); // signal that slot has been filled

print("in putIn() - leaving");

}

public synchronized Object takeOut()

throws InterruptedException {

print("in takeOut() - entering");

while ( slot == null ) {

print("in takeOut() - empty, about to wait()");

wait(); // wait while slot is empty

print("in takeOut() - notified, back from wait()");

}

Object obj = slot;

slot = null; // mark slot as empty

print(

"in takeOut() - emptied slot, about to notifyAll()");

notifyAll(); // signal that slot is empty

print("in takeOut() - leaving");

return obj;

}

private static void print(String msg) {

String name = Thread.currentThread().getName();

System.out.println(name + ": " + msg);

}

}