ThreadCom.java

See TickTock2.java

// Use wait() and notify() to create a ticking clock.

class TickTock {

  String state; // contains the state of the clock

  synchronized void tick(boolean running) {
    if(!running) { // stop the clock
      state = "ticked";
      notify(); // notify any waiting threads
      return;
    }

    System.out.print("Tick ");

    state = "ticked"; // set the current state to ticked

    notify(); // let tock() run
    try {
      while(!state.equals("tocked"))
        wait(); // wait for tock() to complete
    }
    catch(InterruptedException exc) {
      System.out.println("Thread interrupted.");
    }
  }

  synchronized void tock(boolean running) {
    if(!running) { // stop the clock
      state = "tocked";
      notify(); // notify any waiting threads
      return;
    }

    System.out.println("Tock");

    state = "tocked"; // set the current state to tocked

    notify(); // let tick() run
    try {
      while(!state.equals("ticked"))
        wait(); // wait for tick to complete
    }
    catch(InterruptedException exc) {
      System.out.println("Thread interrupted.");
    }
  }
}

class MyThread implements Runnable {
  Thread thrd;
  TickTock2 ttOb;

  // Construct a new thread.
  MyThread(String name, TickTock2 tt) {
    thrd = new Thread(this, name);
    ttOb = tt;
    thrd.start(); // start the thread
  }

  // Begin execution of new thread.
  public void run() {

    if(thrd.getName().compareTo("Tick") == 0) {
      for(int i=0; i<5; i++) ttOb.tick(true);
      ttOb.tick(false);
    }
    else {
      for(int i=0; i<5; i++) ttOb.tock(true);
      ttOb.tock(false);
    }
  }
}

class ThreadCom {
  public static void main(String[] args) {
    TickTock2 tt = new TickTock2();
    MyThread mt1 = new MyThread("Tick", tt);
    MyThread mt2 = new MyThread("Tock", tt);

    try {
      mt1.thrd.join();
      mt2.thrd.join();
    } catch(InterruptedException exc) {
      System.out.println("Main thread interrupted.");
    }
  }
}

Results

C:\ece538\java_thread>java ThreadCom
Tick Tick Tick Tick Tick Tock
Tock
Tock
Tock
Tock

Maintained by John Loomis, updated Mon Nov 19 21:45:07 2012