/**************************************************************
**
** Program : thread_ex.java
**
** Author :  Ryan J. Stradling
**
** Created : July 31, 1996
**
** Revisions :
**
** Purpose :  This applet will display two buttons and two
**			numbers.  When you click on a button the corresponding
**			number will increment.  If you click on it again it
**			will stop counting.  This is to show the independence
**			of threads.  The numbers only count to 50 and then 
**			stop.
**
***************************************************************/

import java.awt.*;

public class thread_ex extends java.applet.Applet implements Runnable {
/* APPLET */
	final static int NUMCOUNTERS = 2;
	final static int SPACING = 23;

	Counter[] counters = new Counter[NUMCOUNTERS];
	Thread updateThread = null;

	boolean[] clicked = new boolean[NUMCOUNTERS];

	public void init() {
		/* Make new counters */
		for (int i = 0; i < NUMCOUNTERS; i++) {
			counters[i] = new Counter();
			counters[i].setPriority(2);
			clicked[i] = false;
		}

		/* Make updateThread for drawing */
		if (updateThread == null ) {
			updateThread = new Thread(this, "Count Program");
			updateThread.setPriority(NUMCOUNTERS+2);
		}
	
	/* Make on/off buttons for threads */
		for (int i = 0; i< NUMCOUNTERS; i++) {
			add(new Button(("ON/OFF " + i))); 

		}
	}

	public boolean action (Event evt, Object arg) {
	/* check for button pushes */

		if (evt.target instanceof Button) {
			check_button((String)arg);
			return true;
		}
		else 
			return false;
	}

	void check_button(String bname) {
	
		// Start updateThread
		if (!updateThread.isAlive())
			updateThread.start();

		for (int i = 0; i<NUMCOUNTERS; i++) {
			if (bname.equals("ON/OFF " + i)) {
				// Start that buttons thread
				if (!counters[i].isAlive())
				{
					// Never started so start it
					counters[i].start();
				}
				else if (clicked[i] == false) {
					// Button hit so resume
					counters[i].resume();
				}
				else if (clicked[i] == true) {
					// Button hit so turn off
					counters[i].suspend();
				}
				clicked[i] = !clicked[i];  // Say button was hit
			}			
		}
	}

	public void paint(java.awt.Graphics g) {
		// Draw the count for the counters on the screen
		for (int i = 0; i<NUMCOUNTERS; i++) {
			g.drawString((""+counters[i].count), 10, (i+1)*SPACING);
		}
	}

	public void run() {

		while (updateThread == Thread.currentThread()) {
		// Repaint until count > 50
			for (int i = 0; i < NUMCOUNTERS; i++) {
				if (counters[i].count <= 50)
				{
					repaint();
					try {
						updateThread.sleep(1000);
					} catch (InterruptedException e) {}
				}
				else counters[i].stop();
			}
			for (int i = 0; i < NUMCOUNTERS; i++) {
				if (counters[i] != null)
					if (counters[i].count > 50) stop();
			}
		}
	}

	public void stop() {
	// Stops all threads
		for (int i = 0; i< NUMCOUNTERS; i++) {
			if (counters[i].isAlive()) {
				counters[i] = null;
			}
		}
		if (updateThread.isAlive()) {
			updateThread = null;
		}
	}

}