Simple Cashiering

Cashiering.java

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
 
public class simpleCashiering extends JFrame implements ActionListener {
	
	private String[] strItems = { "SBW Huawei E1550     $ 850",
					"SmartBro ZTE MF627   $ 800",
					"HP Deskjet D2360     $ 2000",
					"Flash Drive (2GB)    $ 300",
					"PSU 600watts         $ 800",
					"HDD Enclosure        $ 3000 ",
					"HardDisk (600GB)     $ 4500",
					"Computer Casing      $ 5000",
					"LCD Monitor 17inch   $ 3500", 
					"Extension Cable      $ 400" };
									
	private double[] itemPrice = { 850, 800, 2000, 300, 800,
					3000, 4500, 5000, 3500, 400 };
	
	private JList<String> lstItems = new JList<String>( strItems );
	private Container container = getContentPane();
	private JTextArea billTA = new JTextArea( 10,41 );
	private JButton resetB, computeB;
	private JPanel panel = new JPanel();
	private JLabel lblHeader;
	
	public simpleCashiering(){
		setPane();
		setJFrame();
	}
	
	public void setPane(){
		
		lblHeader = new JLabel( "Simple Cashiering" );
		lblHeader.setFont( new Font( "Dialog", Font.BOLD, 20) );
		lblHeader.setHorizontalAlignment( JLabel.CENTER );
		container.add( lblHeader, BorderLayout.NORTH );
		
		lstItems.setFont( new Font("Courier", Font.PLAIN, 12) );
		container.add( new JScrollPane(lstItems), BorderLayout.WEST );
		
		billTA.setFont( new Font("Courier", Font.PLAIN, 12) );
		container.add( new JScrollPane(billTA), BorderLayout.EAST );
		
		computeB = new JButton( "Compute" );
		resetB = new JButton( "   Reset   " );
		
		computeB.addActionListener(this);
		resetB.addActionListener(this);
		

		panel.add(computeB);
		panel.add(resetB);

		container.add( panel, BorderLayout.SOUTH );
	}
	
	public void actionPerformed(ActionEvent ae){
		if( ae.getSource() == computeB)
			displayBill();
		else{
			lstItems.clearSelection();
			billTA.setEditable( true );
			billTA.setText( "" );
			repaint();
		}	
	}
	
	public void setJFrame(){
		setTitle( "Simple Cashiering by Tabs" );
		setSize( 500, 360 );
		setResizable( false );
		setVisible( true );
		setDefaultCloseOperation( EXIT_ON_CLOSE );
		setLocationRelativeTo( null );
	}
	
	public void displayBill(){
		int[] selectedItems = lstItems.getSelectedIndices();
		final double localTax = 0.065;
		double subTotal = 0.0;
		double tax = 0.0;
		double total = 0.0;
		
		billTA.setText( "" );
		billTA.append( "        SIMPLE CASHIERING BY TABS\n\n");
		billTA.append( "---------------- WELCOME ----------------\n\n" );
		
		for(int i=0; i<selectedItems.length; i++){
			billTA.append( strItems[ selectedItems[i] ] + "\n");
			subTotal += itemPrice[ selectedItems[i] ] ;
		}
		
		tax = localTax * subTotal;
		total = tax + subTotal;
		
		billTA.append( String.format( "%nSUB TOTAL\t\t $ %.2f", subTotal ) );
		billTA.append( String.format( "%nTAX      \t\t $ %.2f", tax ) );
		billTA.append( String.format( "%nTOTAL    \t\t $ %.2f", total ) );
		billTA.append( "\n\n\nThank You -- Have a Nice Day");
		billTA.setEditable( false );
	}
    
    public static void main(String[] args) {
    	new simpleCashiering();
    }
}