Using two threads and controlling one from the other in java?

Can someone please help me out.

I need to use two threads in a way that one thread will r开发者_如何学Cun permanently while(true) and will keep track of a positioning pointer (some random value coming in form a method). This thread has a logic, if the value equals something, it should start the new thread. And if the value does not equal it should stop the other thread.

Can someone give me some code snippet (block level) about how to realize this?

Create a class that implements Runnable. There you'll make a run() method.

Like:

public class StackOverflow implements Runnable{

private Thread t = null;

public void run(){
}

public void setAnotherThread(Thread t){
 this.t = t;
}


}

On the main class, you'll create 2 instances of Thread based on the other class you created.

StackOverflow so1 = new StackOverflow();
StackOverflow so2 = new StackOverflow();
Thread t1 = new Thread(so1);
Thread t2 = new Thread(so2)

Then you set one thread in the other, so you can control it.

t1.setAnotherThread(so2);
t2.setAnotherThread(so1);

Then you do what you need to do.

Ok if I'm not mistaken, you want to have one class that could be run as a "Thread" or as a (lets call it) a "sub-Thread". But how to do that with one run method? just declare a boolean variable that specifies whether the thread object is a sub-thread or a parent thread, and accordingly declare two constructors, one would create a parent thread and the other would create a sub thread, and to be able to stop the sub-thread declare another variable called stop that is default to false.

class ThreadExample extends Thread {

private boolean sub = false;
private ThreadExample subThread = null;
public boolean stop = false;
public ThreadExample() {
}

public ThreadExample(boolean sub) {
    this.sub = sub;
}

public void run() {
    if (sub) {
        runSubMethod();
    } else {
        runParentMethod();
    }
}

public void runParentMethod() {
    boolean running = true;
    while (running) {
        if (getRandomValue() == some_other_value) {
            if (getSubThread().isAlive()) {
                continue;
            }
            getSubThread().start();
        } else {
            getSubThread().makeStop();
        }
    }
}

public void runSubMethod(){

    while(true){
        //do stuff
        if (stop)
            break;

    }
}

public int getRandomValue() {
    //your "Random Value"
    return 0;
}

private ThreadExample getSubThread() {
    if (subThread == null) {
        subThread = new ThreadExample(true);
    }
    return subThread;
}
public void makeStop(){
    stop = true;
}

}

Here is a simple idea how you can implement as many threads as you like in a class:

class MultipleThreads{  

   Runnable r1 = new Runnable() {
     public void run() {
       ... code to be executed ...
     }
   };

   //-----

   Runnable r2 = new Runnable() {
     public void run() {
       ... code to be executed ...
     }
   };

   //--- continue as much you like  

   public static void main (String[] args){  

      Thread thr1 = new Thread(r1);
      Thread thr2 = new Thread(r2);
      thr1.start();
      thr2.start();
   }  
}

Hope it helps!!
For communicating between the two threads, one simple solution is to set a boolean type volatile static variable, and have it set from one thread and put it in while(flag) condition in the other thread.
You can control the other thread using this method.
And if you have waiting processes or Thread.sleep() and you want to break the thread without having it to finish it, your interrupts by catching the exception.