// Example 92 from page 69 of Java Precisely second edition (The MIT Press 2005)
// Author: Peter Sestoft (sestoft@itu.dk)


class Printer extends Thread {
  static Object mutex = new Object();
  public void run() {
    for (;;) {
      synchronized (mutex) {
        System.out.print("-");
        Util.pause(100,300);
        System.out.print("/");
      }
      Util.pause(200);
} } }

class Example92 {
  public static void main(String[] args) 
  { new Printer().start(); new Printer().start(); }
}

// Pseudo-random numbers and sleeping threads

class Util {
  public static void pause(int length) 
  { try { Thread.sleep(length); } catch (InterruptedException x) {} }

  public static void pause(int a, int b) { pause(random(a, b)); }

  public static int random(int a, int b) 
  { return (int)(a + (b-a+1) * Math.random()); }
}