Please, see this tutorial
http://tutorials.jenkov.com/java-concurrency/semaphores.html
Example of Semaphore as a lock:
public class Semaphore {
private static final Logger LOG = LoggerFactory.getLogger(Semaphore.class);
private boolean signal = true; // It means that the first threads could get the light green
/**
*
*/
public Semaphore() {
super();
}
/**
*
*/
public synchronized void release() {
this.signal = true;
this.notifyAll();
}
/**
*
*/
public synchronized void take() {
while(this.signal == false) {
try {
wait();
} catch (InterruptedException e) {
LOG.error(e.getMessage(), e);
}
}
this.signal = false;
}
}
