//////////////////////////////////////////////////////////////
// From JAVA PROGRAMMING: FROM THE BEGINNING, by K. N. King //
// Copyright (c) 2000 W. W. Norton & Company, Inc.          //
// All rights reserved.                                     //
// This program may be freely distributed for class use,    //
// provided that this copyright notice is retained.         //
//                                                          //
// ConvertTemp.java (Chapter 12, page 522)                  //
//////////////////////////////////////////////////////////////

// Converts a Fahrenheit temperature entered by the user to
// Celsius, or vice versa

import java.awt.*;
import java.awt.event.*;
import jpb.*;

// Driver class
public class ConvertTemp {
    public static void main(String[] args) {
        Frame frame = 
            new ConvertTempFrame("Temperature Conversion");
        frame.setSize(150, 75);
        frame.setVisible(true);
    }
}

// Frame class
class ConvertTempFrame extends Frame {
    private TextField fahrenField = new TextField();
    private TextField celsiusField = new TextField();

    // Constructor
    public ConvertTempFrame(String title) {
        // Set title for frame and choose layout
        super(title);
        setLayout(new GridLayout(2, 2));

        // Add Fahrenheit label and text field to frame; attach
        // listener to text field
        add(new Label("Fahrenheit"));
        add(fahrenField);
        fahrenField.addActionListener(new FahrenheitListener());

        // Add Celsius label and text field to frame; attach
        // listener to text field
        add(new Label("Celsius"));
        add(celsiusField);
        celsiusField.addActionListener(new CelsiusListener());

        // Attach window listener
        addWindowListener(new WindowCloser());
    }

    // Listener for fahrenField
    class FahrenheitListener implements ActionListener {
        public void actionPerformed(ActionEvent evt) {
            String fahrenheitString = fahrenField.getText();
            double fahrenheit = Convert.toDouble(fahrenheitString);
            double celsius = (fahrenheit - 32.0) * 5.0 / 9.0;
            celsius = Math.rint(celsius * 100.0) / 100.0;
            celsiusField.setText(celsius + "");
        }
    }

    // Listener for celsiusField
    class CelsiusListener implements ActionListener {
        public void actionPerformed(ActionEvent evt) {
            String celsiusString = celsiusField.getText();
            double celsius = Convert.toDouble(celsiusString);
            double fahrenheit = celsius * 9.0 / 5.0 + 32.0;
            fahrenheit = Math.rint(fahrenheit * 100.0) / 100.0;
            fahrenField.setText(fahrenheit + "");
        }
    }

    // Listener for window
    class WindowCloser extends WindowAdapter {
        public void windowClosing(WindowEvent evt) {
            System.exit(0);
        }
    }
}