Re: basic GUI question

In article <h356hm$f7t$1@news.eternal-september.org>,
 markspace <nospam@nowhere.com> wrote:

[...]


[...]

Your excellent example prompted me to update my GUI launcher that uses
exec() to run programs in a separate JVM:

<code>
package gui;

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;

/** @author John B. Matthews */
public class Launcher extends JPanel implements Runnable {

    private final JButton launch = new JButton();
    private final JLabel label = new JLabel();
    ProcessBuilder pb = new ProcessBuilder(
        "java", "-cp", "build/classes", "gui.DialogTest");
    private volatile Process proc;

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                createGUI();
            }
        });
    }

    private static void createGUI() {
        final JFrame frame = new JFrame();
        frame.setLayout(new GridLayout(0, 1));
        frame.add(new Launcher());
        frame.add(new Launcher());
        frame.add(new Launcher());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }

    public Launcher() {
        this.setPreferredSize(new Dimension(225, 50));
        launch.addActionListener(new ActionListener() {
            //@Override
            public void actionPerformed(ActionEvent e) {
                if (proc == null) {
                    launch.setText("Terminate");
                    label.setText("Status: run");
                    new Thread(Launcher.this).start();
                } else {
                    proc.destroy();
                    reset();
                }
            }
        });
        this.add(launch);
        this.add(label);
        reset();
    }

    //@Override
    public void run() {
        try {
            proc = pb.start();
            int status = proc.waitFor();
        } catch (IOException ex) {
            ex.printStackTrace();
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                reset();
            }
        });
    }

    private void reset() {
        proc = null;
        launch.setText("Launch");
        label.setText("Status: idle");
    }
}

class DialogTest {

    public static void main(String... args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JOptionPane.showMessageDialog(null, "Running",
                    "Test", JOptionPane.INFORMATION_MESSAGE);
                System.exit(0);
            }
        });
    }
}
</code>

--
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>