Swing first class w/ FCM.

I got to play with the First-Class methods (FCM) prototype; it's pretty cool. So here we go: Java version then FCM version.

To run the FCM version: compile it using the prototype; then simply type: java FCMGui and you're set. If you need help feel free to e-mail me.

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.SwingUtilities;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

/**
 * Created: Mar 19, 2008 5:48:43 PM
 *
 * @author Robert O'Connor
 */
public class UsualJavaGui {
    JFrame frame = new JFrame("Usual Java Example");
    JButton button = new JButton("Press me");

    public UsualJavaGui() {
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println("Button pressed");
            }
        });
        frame.add(button);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);

    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new UsualJavaGui();
            }
        });

    }
}

Standard java Swing GUI with a frame and a button; press it a message appears in your console. Now, FCM version:

import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.SwingUtilities;
import java.awt.event.ActionEvent;

/**
 * Created: Mar 21, 2008 6:55:52 PM
 *
 * @author Robert O'Connor
 */
public class FCMGui {
    JFrame frame = new JFrame("FCM Example");
    JButton button = new JButton("Press Me");

    public FCMGui() {
        button.addActionListener(#(ActionEvent evt) {
            System.out.println("Button pressed");
        });
        frame.add(button);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(# { new FCMGui();
        }); 

    }
}

Same thing: But what the hell is going on? First off, what we declared is called an anonymous inner method; if you remember, it's a First-Class method meaning that it exists in itself. Currently in java, a method must be enclosed in a class, and cannot be referred to on a first-class level.

Swinging: BGGA style.

So, to continue on with my playing w/ java closures, I now present Swing event handling: BGGA Style. Again, to compile this you will need the BGGA prototype. You can run it using your installed jre.

First, i'll show you the java version:

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.SwingUtilities;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

/**
 * Created: Mar 19, 2008 5:48:43 PM
 *
 * @author Robert O'Connor
 */
public class UsualJavaGui {
    JFrame frame = new JFrame("Usual Java Example");
    JButton button = new JButton("Press me");

    public UsualJavaGui() {
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println("Button pressed");
            }
        });
        frame.add(button);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);

    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new UsualJavaGui();
            }
        });

    }
}

I think you get the gist of what it does. Now the BGGA version.

import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.SwingUtilities;
import java.awt.event.ActionEvent;

/**
 * Created: Mar 19, 2008 7:35:15 PM
 *
 * @author Robert O'Connor
 */
public class BGGAGui {
    JFrame frame = new JFrame("BGGA Frame");
    JButton button = new JButton("Press me");

    public BGGAGui() {
        button.addActionListener({ActionEvent evt => System.out.println("Button pressed");});
        frame.add(button);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        // thanks to neil gafter!
        SwingUtilities.invokeLater({ => new BGGAGui(); }); 

    }
}

What occurs within the the addActionListener() is that when you click the button, that closure is invoked; it does the same thing the java one does (print "Button pressed" to the screen). I'm not sure how to write the invokeLater() method using BGGA to reduce its verbosity. If anybody knows, could you tell me? When the code is executed; the closure is executed and a frame is displayed; yadda yadda.

Concise Instance Creation Expressions (CICE)

Another proposal CICE is being put out there for Java 7. To compile the code posted here you will need the latest cice prototype. You can run it using your installed jre. Now, let's get down to the code! First I'm gonna show you the current Java version, then I'll show you the CICE version.

Java Version

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.SwingUtilities;

/**
 * Created: Mar 19, 2008 5:48:43 PM
 *
 * @author Robert O'Connor
 */
public class UsualJavaGui {
    JFrame frame = new JFrame("Usual Java Example");
    JButton button = new JButton("Press me");

    public UsualJavaGui() {
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println("Button pressed");
            }
        });
        frame.add(button);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);

    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new UsualJavaGui();
            }
        });

    }
}

Now, the main problem people have with java is that it's overly verbose, and they're right in that aspect. CICE aims to reduce that verbosity; by making it more concise and to the point. Now you know the basics of that implementation; it's a simple JFrame with a button that when you click it will display a message in your console.

Now the same app but with CICE:

import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.SwingUtilities;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

/**
 * Created: Mar 19, 2008 5:57:45 PM
 *
 * @author Robert O'Connor
 */
public class CICEGui {
    JFrame frame = new JFrame("CICE Gui");
    JButton button = new JButton("Press me");

    public CICEGui() {
        button.addActionListener(ActionListener(ActionEvent e){
            System.out.println("Button pressed");
        });
        frame.add(button);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }

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

The above is a lot less verbose; What's missing? You'll notice the difference primarily in the main() method and the addActionListener() method call to attach the event listener to my JButton.
What's missing? That's right the

public void run() { ... }

and

public void actionPerformed(ActionEvent e) { ... }

How can this be and how do I get access to the ActionEvent reference? Well notice the following:

button.addActionListener(ActionListener(ActionEvent e) {
       System.out.println("Button pressed");
   });

I passed in the ActionEvent parameter to the Concise Instance Creation Expression! Using CICE, I was able to eliminate the methods. Also note, that I was able to eliminate using the word new is not needed with CICE. I was also able to state my intent cleanly, and in a lot less verbose way. How many lines were eliminated between the Java version and the CICE version?

(rob-laptop)rob@~/playground/src/main/java$ wc -l misc/UsualJavaGui.java misc/CICEGui.java 
  43 misc/UsualJavaGui.java
  34 misc/CICEGui.java
  77 total
(rob-laptop)rob@~/playground/src/main/java$ 

Well, that's 9 lines! Why should you have to type out the method definition if there is only ONE method in the interface or abstract class?