gistfile1.txt

public class Semaphore {

private int count;

public Semaphore(int count) {
 this.count = count;
}

public synchronized void p() {
 count--;
 while (count < 0) {
  try {
   this.wait();
  } catch(Exception e) {
   e.printStackTrace();
  }
 }
}

public synchronized void v() {
 count++;
 if (count <= 0) {
  this.notify();
 }
}

}