// file: Lesson2.java
// type: Java code
// note: Handling buttons and fields
// author: Gregory C. Walsh
// date: 3.9.1999

import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.*;
import java.applet.Applet;

public class Lesson2 extends Applet implements ActionListener{
    TextField input;
    Label output;
    Button zap, go, stop, reload;
    Font f;
    int ammo;
    
    public void init () {
	// Initialize amount of Ammo.  This is 
	// a parameter which may be passed from the 
	// html code which calls the applet.
	// The default value is 6

	String buffer = getParameter("ammo");
	if(buffer == null) {
	    ammo = 6;
	}
	else {
	    ammo = (int) Integer.valueOf(buffer).intValue();

	}
	// Pick Font for GUI objects

	f = new Font("TimesRoman",Font.PLAIN,16);

	// First generate the GUI objects and set fonts on gui's....

	output = new Label( "Ammunition = " + ammo,Label.CENTER);
	output.setFont(f);

	input  = new TextField( 20 );
	input.setFont(f);

	zap = new Button( "Zap!");
	zap.setFont(f);

	go = new Button("Go");
	go.setFont(f);

	stop = new Button("Stop");
	stop.setFont(f);

	reload = new Button("Reload");
	reload.setFont(f);

	// Connect GUI components to actionlistener ....

	zap.addActionListener(this);
	go.addActionListener(this);
	stop.addActionListener(this);
	reload.addActionListener(this);

	// Now add the components to the Applet 

	add(output);
	add(zap);
	add(go);
	add(stop);
	add(reload);
	add(input);

	// Configure the initial button state

	go.setEnabled(true);
	stop.setEnabled(false);
    }

    // Actionlistener for the buttons .....
    
    public void actionPerformed(ActionEvent e) {

	String command = e.getActionCommand();

	if( (command == "Zap!") && (stop.isEnabled()) ) {
	    if(ammo>0) {
		ammo--;
		Toolkit.getDefaultToolkit().beep();     
		output.setText("Ammo: " + ammo);
		input.setText(input.getText() + " Zap!!");
		if(ammo == 0) output.setText("Empty!");
	    }
	    else 
		output.setText("Out of ammo!");
	}
	
	if(command == "Go") {
	    showStatus(" ... Zap ready to go!");
	    go.setEnabled(false);
	    output.setText("Ammo: " + ammo);
	    stop.setEnabled(true);
	}

	if(command == "Reload") {
	    showStatus(" ... Zap on safety!");
	    go.setEnabled(true);
	    stop.setEnabled(false);
	    output.setText("Ammo reloaded");
	    ammo = 6;
	    input.setText("");
	}

	if(command == "Stop") {
	    showStatus(" ... Zap on safety!");
	    go.setEnabled(true);
	    stop.setEnabled(false);
	    input.setText("");
	}
	return;
    }
}