Re: Could this be done better

From:

Cecil Westerhof <Cecil@decebal.nl>

Newsgroups:

comp.lang.java.programmer

Date:

Tue, 25 Nov 2014 00:55:52 +0100

Message-ID:

<871tos6tmf.fsf@Equus.decebal.nl>

Op Monday 24 Nov 2014 18:41 CET schreef Knute Johnson:

// private classes
private class Colour {
// public
public Colour(Color color, String description) {
this.color = color;
this.description = description;
}

public Color getColor() {
return color;
}

public String getDescription() {
return description;
}

// private
private Color color;
private String description;
}

private class SwitchColour extends TimerTask {
public void run() {
updateColour(getNextColour());
}
}

//private functions
private Colour getCurrentColour() {
return colours[currentColour];
}

private Colour getNextColour() {
currentColour = (currentColour + 1) % colours.length;
return getCurrentColour();
}

As much as I like your class Colour, it is probably easier and
simpler to use an enum in this case.

import java.awt.*;

public class test {
enum Colours {
Red(Color.RED),Blue(Color.BLUE),Green(Color.GREEN);

private final Color value;

Colours(Color value) {
this.value = value;
}

public Color value() {
return value;
}
}

public static void main(String... args) {
System.out.println(Colours.Red);
System.out.println(Colours.Red.value());

System.out.println();

for (Colours colour : Colours.values())
System.out.println(colour+":"+colour.value());
}
}

C:\Users\Knute Johnson>java test
Red
java.awt.Color[r=255,g=0,b=0]

Red:java.awt.Color[r=255,g=0,b=0]
Blue:java.awt.Color[r=0,g=0,b=255]
Green:java.awt.Color[r=0,g=255,b=0]

I did not know that you could use enums in that way.

But I see two problems.
1. You can not change the list of colours. (Not a problem in my case.)
2. Officially enums should be all caps.

The code is now:
    import java.awt.*;
    import java.util.*;

    import javax.swing.*;

    @SuppressWarnings("serial")
    public class ColourCycling extends JFrame {
        // public functions
        public ColourCycling() {
            java.util.Timer colourTimer = new java.util.Timer();

            getContentPane().setBackground(background);
            setLayout(new GridBagLayout());
            label = new JLabel(description + " : " + "XXXXXXXXXXXXXXX");
            label.setFont(new Font("serif", Font.BOLD, 25));
            add(label);
            pack();
            setSize(getWidth(), 3 * getHeight());
            label.setBackground(background);
            updateColour(getCurrentColour());
            colourTimer.schedule(new SwitchColour(), delay, delay);
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            setTitle(description);
            setVisible(true);
        }

        public static void main(String[] args) {
            SwingUtilities.invokeLater(new Runnable() {
                    public void run() {
                        new ColourCycling();
                    }
                });
        }

        // private classes
        private enum Colours {
            Blue(Color.BLUE),
            Red(Color.RED),
            Orange(Color.ORANGE),
            Yellow(Color.YELLOW),
            Green(Color.GREEN),
            Cyan(Color.CYAN),
            Magenta(Color.MAGENTA),
            Brown(new Color(0x9C, 0x5D, 0x52)),
            ;

            private final Color value;

            Colours(Color value) {
                this.value = value;
            }

            public Color value() {
                return value;
            }
        }

        private class SwitchColour extends TimerTask {
            public void run() {
            SwingUtilities.invokeLater(new Runnable() {
                    public void run() {
                        updateColour(getNextColour());
                    }
                });
            }
        }

        //private functions
        private Colours getCurrentColour() {
            return Colours.values()[currentColour];
        }

        private Colours getNextColour() {
            currentColour = (currentColour + 1) % Colours.values().length;
            return getCurrentColour();
        }

        private void updateColour(Colours newColour) {
            label.setForeground(newColour.value());
            label.setText(description + " : " + newColour);
        }

        // private variables
        private Color background = Color.LIGHT_GRAY;
        private int currentColour = 0;
        private int delay = 4000;
        private String description = "JTextArea Color Change Example";
        private JLabel label;

    }

--
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof