[RESOLVED] Threading in Java to display numbers.

[eranga262154]

Hi all,

I want to print some numbers, say starting from 1 and increment by 1, in a specific interval, say each one second.

I want to use Java thread to do this. Can you guys give me a clue.

I've try this, but I can't execute on main(). When I call the init() method, thread stopped.

public class Counter extends Applet implements Runnable {
	Thread t;	
	int Count;

    @Override
	public void init()	
	{	
		Count=0;
		t=new Thread(this);
		t.start();
	}

    @Override
	public boolean mouseDown(Event e,int x, int y)
	{	
		t.stop();
		return true;
	}

	public void run()
	{
		while(true)
		{
			Count++;
			repaint();
			try {
				Thread.sleep(10);
			} catch (InterruptedException e) {}
		}
	}

    @Override
	public void paint(Graphics g)
	{
		//g.drawString(Integer.toString(Count),10,10);
		System.out.println("Count= "+Count);
	}

    @Override
	public void stop()
	{
		t.stop();
	}
}

public class Main {
    public static void main(String[] args) {
         
        Counter ss = new Counter();
        ss.run();
    }

}

Thanks.

[ComputerJy]

Try this

import java.util.logging.Level;
import java.util.logging.Logger;

public class Util {

    public static void main(String[] args) throws Exception {
	Thread th = new Thread(new Runnable() {

	    public void run() {
		int i = 0;
		while (i <= 10) {
		    try {
			System.out.println(i++);
			Thread.sleep(1000);
		    } catch (InterruptedException ex) {
			Logger.getLogger(Util.class.getName()).log(Level.SEVERE, null, ex);
		    }
		}
	    }
	});
	th.start();
    }
}

[ComputerJy]

And you can't use the main method to display an applet, you must have a containing browser. so put it in an HTML page

[eranga262154]

Oh dear, it's a terrible mistake I have make. Yes you are right, and mess-up on my IDE I think.

[eranga262154]

Try this

import java.util.logging.Level;
import java.util.logging.Logger;

public class Util {

    public static void main(String[] args) throws Exception {
	Thread th = new Thread(new Runnable() {

	    public void run() {
		int i = 0;
		while (i <= 10) {
		    try {
			System.out.println(i++);
			Thread.sleep(1000);
		    } catch (InterruptedException ex) {
			Logger.getLogger(Util.class.getName()).log(Level.SEVERE, null, ex);
		    }
		}
	    }
	});
	th.start();
    }
}

Thanks pal.

This code working as I expected. I've implement it on a button click-event and it works fine. But mess up one thing on my GUI.

Until the thread execution completed, all the controls(I mean buttons, check boxes, etc) are freeze. That mean I can't click any button, check-uncheck a check box and so on. Not the whole frame, I can move frame only.

What can be wrong.

After execution of the thread completed, I can use all controls.

[ComputerJy]

Thread.sleep(1000); causes the main thread to suspend all execution for 1000 milliseconds

[eranga262154]

Yes, initially I guess that do something like this in that thread.

        int x = 1;
	Thread th = new Thread(new Runnable() {

	    public void run(){
		int counter = 0;
		while(counter <= 10000){ 
			System.out.println(counter++);
		}
            }
	});

But it not work. As I said early, until print the number 10000 to console, I can't use any controls on the GUI.

Any idea pal...

[ComputerJy]

Actually something is wrong with the way you're organizing your code. Because a simple test

import java.util.logging.Level;
import java.util.logging.Logger;

public class Util {

    public static void main(String[] args) throws Exception {
	Thread th = new Thread(new Runnable() {

	    public void run() {
		int i = 0;
		while (i <= 10) {
		    try {
			System.out.println(i++);
			Thread.sleep(1000);
		    } catch (InterruptedException ex) {
			Logger.getLogger(Util.class.getName()).log(Level.SEVERE, null, ex);
		    }
		}
	    }
	});
	th.start();
	Thread.sleep(500);
	for (char c = 'a'; c <= 'z'; c++) {
	    System.out.println(c);
	}
    }

    private Util() {
    }
}

proves that if you call Thread.sleep the current thread only will be suspended not the whole system.

[eranga262154]

Ok, I try what you say. But I got an error on following lines. Actually I cant use the thread th again.

th.start();

Error: package th does not exit

Thread.sleep(500);

Error: illegal start of type


I used the thread in the button click event as follows.

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
        Util appProcess = new Util();
        appProcess.th.run();        
    }

But still the same thing is happened. All those things going on two separate classes right now, as you can see I have create instance for the Util class where I have implement my thread.

[eranga262154]

Ok pal, I have observed one thing here. I simply create a thread in the same class where I create GUI. Here is my thread.

        Thread testTH = new Thread(new Runnable() {

	    public void run(){
		int counter = 0;
		while(counter <= 10){ 
		    try {
			System.out.println(counter++);
			Thread.sleep(1000);
		    } 
                    catch (InterruptedException ex) {
			 System.out.println(ex);
		    }
		}
            }
   });

Then in the click-event I simply call the start() of the thread.

testTH.start();

It works fine. So what is wrong with my code.

[ComputerJy]

I don't know
I haven't seen your code!!

[eranga262154]

Ya it's true.