package net.jcip.examples; import net.jcip.annotations.*; /** * ThreadGate *
* Recloseable gate using wait and notifyAll * * @author Brian Goetz and Tim Peierls */ @ThreadSafe public class ThreadGate { // CONDITION-PREDICATE: opened-since(n) (isOpen || generation>n) @GuardedBy("this") private boolean isOpen; @GuardedBy("this") private int generation; public synchronized void close() { isOpen = false; } public synchronized void open() { ++generation; isOpen = true; notifyAll(); } // BLOCKS-UNTIL: opened-since(generation on entry) public synchronized void await() throws InterruptedException { int arrivalGeneration = generation; while (!isOpen && arrivalGeneration == generation) wait(); } }