/**
 * File name: WageCalculatorOptionPane.java
 * Author: Hongyan Wang.   Modified by David Wills to use JOptionPane
 *
 * Description: The program accepts an employee's pay rate and number of hours 
 * worked in a week, and calculates the wage the employee earned for that week. 
 *
 * Others: The program has minimum error checking. It doesn't check the validity 
 * of number of hours worked. The program uses JOptionPane for input.
 */

import java.text.*;				// to use DecimalFormat
import javax.swing.*;

public class WageCalculatorOptionPane {
    // Constants
    private static final double MAX_HOURS = 40.0;   // Maximum normal work hours
    private static final double OVERTIME = 1.5;     // Overtime pay rate factor
    
    // main function
    public static void main (String[] args) {
	double payRate;       // Employee's pay rate
	double hours;         // Hours worked
	double wages;         // Wages earned
	String input;
	
	while (true) {
	    // Get info. 
	    input = JOptionPane.showInputDialog ("Enter pay rate (enter 0 or a negative number to quit): ");     
	    payRate = Double.parseDouble( input );	
	    
	    if (payRate <= 0.0)
		break;			// end of all employees; exit the loop
	    
	    input = JOptionPane.showInputDialog ("Enter hours worked: ");
	    hours = Double.parseDouble( input );                        
	    
	    // Calculate wage based on pay rate and hours worked
	    if (hours > MAX_HOURS)                  // Is there overtime?
		wages = (MAX_HOURS * payRate) +     // Yes
		    (hours - MAX_HOURS) * payRate * OVERTIME;
	    else
		wages = hours * payRate;            // No
	    
	    // Display the result
	    DecimalFormat d2 = new DecimalFormat ("0.00");
	    
	    JOptionPane.showMessageDialog (null, "The wage should be " + 
					   d2.format (wages));
	}
    }
}