SuspendResume.java

package chapter11;

//Suspending and resuming a thread the modern way

class NewThread5 implements Runnable {
    String name; //name of thread
    Thread t;
    boolean suspendFlag;

    public NewThread5(String threadName) {
        this.name = threadName;
        t = new Thread(this, name);
        System.out.println("New Thread " + t);
        suspendFlag = false;
    }

    //This is the entry point for the thread
    public void run() {
        try {
            for (int i = 15; i > 0; i--) {
                System.out.println(name + " : " + i);
                Thread.sleep(200);
                synchronized (this) {
                    while (suspendFlag) {
                        wait();
                    }
                }
            }
        } catch (InterruptedException e) {
            System.out.println(name + " : interrupted");
        }
        System.out.println(name + " exiting");
    }

    synchronized void mysuspend() {
        suspendFlag = true;
    }

    synchronized void myresume() {
        suspendFlag = false;
        notify();
    }
}

public class SuspendResume {
    public static void main(String[] args) {
        NewThread5 ob1 = new NewThread5("One");
        NewThread5 ob2 = new NewThread5("Two");
        ob1.t.start(); //Start the thread
        ob2.t.start(); //Start the thread
        try {
            Thread.sleep(1000);
            ob1.mysuspend();
            System.out.println("Suspending thread One");
            Thread.sleep(1000);
            ob1.myresume();
            System.out.println("Resuming thread One");
            ob2.mysuspend();
            System.out.println("Suspending thread Two");
            Thread.sleep(1000);
            ob2.myresume();
            System.out.println("Resuming thread Two");

        } catch (InterruptedException e) {
            System.out.println("Main Thread Interrupted");
        }

        //Wait for threads to finish
        try {
            System.out.println("Waiting for threads to finish");
            ob1.t.join();
            ob2.t.join();

        } catch (InterruptedException e) {
            System.out.println("Main Thread Interrupted");
        }
        System.out.println("Main Thread Exiting");
    }
}