Time Zone

import javax.swing.*;       
import java.awt.*;          
public class Time_Main extends JFrame{

    private JButton YorkButton, LouisButton, SydButton, LondonButton;
    private JTextField YorkField, LouisField, SydField, LondonField;
    
    public Time_Main()
	{
	    YorkButton = new JButton("New York");
	    LouisButton = new JButton("St. Louis");
	    SydButton = new JButton("Sydney");
	    LondonButton = new JButton("London");
		
	    YorkField = new JTextField (" " , 6);
	    LouisField = new JTextField (" " , 6);
	    SydField = new JTextField (" " , 6);
	    LondonField = new JTextField (" " , 6);
	    
		FlowLayout layout = new FlowLayout ();
		
		Container mainWindow = getContentPane();
		mainWindow.setLayout (layout);
		
		mainWindow.add(YorkField);
		mainWindow.add(LouisField);
		mainWindow.add(YorkButton);
		mainWindow.add(LouisButton);
		
		mainWindow.add(SydField);
		mainWindow.add(LondonField);
		mainWindow.add(SydButton);
		mainWindow.add(LondonButton);
		
		
		
		YorkButton.addActionListener(new YorkButton (this));
		LouisButton.addActionListener(new LouisButton (this));
		SydButton.addActionListener(new SydneyButton (this));
		LondonButton.addActionListener(new LondonButton (this));

		
		addWindowListener(new GenWindowList());
	}
	
	public void YorkButton(){
	    String str = YorkField.getText().trim();
	    double york = (new Double (str)).doubleValue();
	    
	    double louis = york - 100;
	    double london = york + 500;
	    double syd = york + 1300;
	    
	    if(louis>2400)
	    louis=louis-2400;
	    
	    if(louis<2400)
	    louis=louis+2400;
	    
	    if(syd>2400)
	    syd=syd-2400;
	    
	    if(syd<2400)
	    syd=syd+2400;
	    
	    if(london>2400)
	    london=london-2400;
	    
	    if(london<2400)
	    london=london+2400;
	    
	    LouisField.setText("" + louis);
	    SydField.setText("" + syd);
	    LondonField.setText("" + london);
	}
	
	public void LouisButton(){
	    String str = LouisField.getText().trim();
	    double louis = (new Double (str)).doubleValue();
	    
	    double york = louis + 100;
	    double london = louis + 600;
	    double syd = louis + 1400;
	    
	    if(york>2400)
	    york=york-2400;

	    if(york<2400)
	    york=york+2400;
	    
	    if(syd>2400)
	    syd-=2400;

	    if(syd<2400)
	    syd+=2400;
	    
	    if(london>2400)
	    london-=2400;

	    if(london<2400)
	    london+=2400;
	    
	    YorkField.setText("" + york);
	    SydField.setText("" + syd);
	    LondonField.setText("" + london);
	}
	
	public void LondonButton(){
	    String str = LondonField.getText().trim();
	    double london = (new Double (str)).doubleValue();
	    
	    double louis = london - 600;
	    double york = london - 500;
	    double syd = london + 800;
	    
	    if(louis>2400)
	    louis-=2400;

	    if(louis<2400)
	    louis+=2400;
	    
	    if(syd>2400)
	    syd-=2400;

	    if(syd<2400)
	    syd+=2400;
	    
	    if(york>2400)
	    york=york-2400;

	    if(york<2400)
	    york=york+2400;
	    
	    LouisField.setText("" + louis);
	    SydField.setText("" + syd);
	    YorkField.setText("" + york);
	}
	
	public void SydneyButton(){
	    String str = SydField.getText().trim();
	    double syd = (new Double (str)).doubleValue();
	    
	    double louis = syd - 1400;
	    double london = syd - 800;
	    double york = syd - 1300;
	    
	    if(louis>2400)
	    louis=louis-2400;

	    if(louis<2400)
	    louis=louis-2400;
	    
	    if(york>2400)
	    york=york-2400;

	    if(york<2400)
	    york=york+2400;
	    
	    if(london>2400)
	    london=london-2400;

	    if(london<2400)
	    london=london-2400;
	    
	    LouisField.setText("" + louis);
	    LondonField.setText("" + london);
	    YorkField.setText("" + york);
	}
	public static void main (String [] args){
		JFrame frm = new Time_Main ();
		frm.setSize (200, 170);
		frm.setVisible(true);			
	}
}