How to wire one pane to another

Question

How do I wire output to paneWithList?

PaneWithList has a listener on its JList so that the selected row is output to the console. How can I direct that output to the JTextPane on output?

Could PaneWithList fire an event which Main picks up? Would PropertyChangeSupport suffice?

Main.java:

package dur.bounceme.net;

import javax.swing.JTabbedPane;

public class Main {

    private static JTabbedPane tabs;
    private static PaneWithList paneWithList;
    private static PaneWithTable paneWithTable;
    private static Output output;

    public static void main(String[] args) {
        tabs = new javax.swing.JTabbedPane();
        paneWithList = new PaneWithList();
        paneWithTable = new PaneWithTable();
        tabs.addTab("list", paneWithList);
        tabs.addTab("table", paneWithTable);
        tabs.addTab("output", output);
    }
}

Answer 1

Here's an example using the observer pattern, also seen here, here and here. Note that it would also be possible to listen to the combo's model.

import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.*;

/**
* @see http://en.wikipedia.org/wiki/Observer_pattern
* @see https://stackoverflow.com/a/10523401/230513
*/
public class PropertyChangeDemo {

    public PropertyChangeDemo() {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setResizable(false);
        f.add(new ObserverPanel());
        f.pack();
        f.setLocationByPlatform(true);
        f.setVisible(true);
    }

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

            @Override
            public void run() {
                PropertyChangeDemo example = new PropertyChangeDemo();
            }
        });
    }
}

class ObserverPanel extends JPanel {

    private JLabel title = new JLabel("Value received: ");
    private JLabel label = new JLabel("null", JLabel.CENTER);

    public ObserverPanel() {
        this.setBorder(BorderFactory.createTitledBorder("ObserverPanel"));
        JPanel panel = new JPanel(new GridLayout(0, 1));
        panel.add(title);
        panel.add(label);
        this.add(panel);
        ObservedPanel observed = new ObservedPanel();
        observed.addPropertyChangeListener(new PropertyChangeListener() {

            @Override
            public void propertyChange(PropertyChangeEvent e) {
                if (e.getPropertyName().equals(ObservedPanel.PHYSICIST)) {
                    String value = e.getNewValue().toString();
                    label.setText(value);
                }
            }
        });
        this.add(observed);
    }
}

class ObservedPanel extends JPanel {

    public static final String PHYSICIST = "Physicist";
    private static final String[] items = new String[]{
        "Alpher", "Bethe", "Gamow", "Dirac", "Einstein"
    };
    private JComboBox combo = new JComboBox(items);
    private String oldValue;

    public ObservedPanel() {
        this.setBorder(BorderFactory.createTitledBorder("ObservedPanel"));
        combo.addActionListener(new ComboBoxListener());
        this.add(combo);
    }

    private class ComboBoxListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent ae) {
            String newValue = (String) combo.getSelectedItem();
            firePropertyChange(PHYSICIST, oldValue, newValue);
            oldValue = newValue;
        }
    }
}

Answer 2

I'd be use JMenu with JMenuItems with contents layed by using CardLayout rather than very complicated JTabbedPane(s)

Answer 3

For my own reference, and for anyone using the Netbeans GUI builder, this works so far as it goes:

The PanelWithList class:

package dur.bounceme.net;

public class PanelWithList extends javax.swing.JPanel {

    public PanelWithList() {
        initComponents();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jScrollPane1 = new javax.swing.JScrollPane();
        jList1 = new javax.swing.JList();
        jScrollPane2 = new javax.swing.JScrollPane();
        jTextArea1 = new javax.swing.JTextArea();

        jList1.setModel(new javax.swing.AbstractListModel() {
            String[] strings = { "Item 1", "Item 2", "Item 3", "Item 4", "Item 5" };
            public int getSize() { return strings.length; }
            public Object getElementAt(int i) { return strings[i]; }
        });
        jList1.setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION);
        jList1.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                jList1MouseClicked(evt);
            }
        });
        jList1.addKeyListener(new java.awt.event.KeyAdapter() {
            public void keyReleased(java.awt.event.KeyEvent evt) {
                jList1KeyReleased(evt);
            }
        });
        jScrollPane1.setViewportView(jList1);

        jTextArea1.setColumns(20);
        jTextArea1.setRows(5);
        jScrollPane2.setViewportView(jTextArea1);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
        this.setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(54, 54, 54)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 247, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 308, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(167, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(35, 35, 35)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addComponent(jScrollPane2)
                    .addComponent(jScrollPane1))
                .addContainerGap(166, Short.MAX_VALUE))
        );
    }// </editor-fold>                        

    private void jList1MouseClicked(java.awt.event.MouseEvent evt) {                                    
        row();
    }                                   

    private void jList1KeyReleased(java.awt.event.KeyEvent evt) {                                   
        row();
    }                                  
    // Variables declaration - do not modify                     
    private javax.swing.JList jList1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JScrollPane jScrollPane2;
    private javax.swing.JTextArea jTextArea1;
    // End of variables declaration                   

    private void row() {
        Object o = jList1.getSelectedValue();
        String s = (String)o;
        jTextArea1.setText(s);
        this.firePropertyChange("list", -1, 1);
    }
}

and Frame.java as a driver:

package dur.bounceme.net;

public class Frame extends javax.swing.JFrame {

    public Frame() {
        initComponents();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        jTabbedPane1 = new javax.swing.JTabbedPane();
        panelWithList1 = new dur.bounceme.net.PanelWithList();
        panelWithTable1 = new dur.bounceme.net.PanelWithTable();
        newJPanel1 = new dur.bounceme.net.PanelWithCombo();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        panelWithList1.addPropertyChangeListener(new java.beans.PropertyChangeListener() {
            public void propertyChange(java.beans.PropertyChangeEvent evt) {
                panelWithList1PropertyChange(evt);
            }
        });
        jTabbedPane1.addTab("tab1", panelWithList1);
        jTabbedPane1.addTab("tab2", panelWithTable1);
        jTabbedPane1.addTab("tab3", newJPanel1);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 937, Short.MAX_VALUE)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addContainerGap()
                    .addComponent(jTabbedPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 913, Short.MAX_VALUE)
                    .addContainerGap()))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 555, Short.MAX_VALUE)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addContainerGap()
                    .addComponent(jTabbedPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 521, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addContainerGap(22, Short.MAX_VALUE)))
        );

        pack();
    }// </editor-fold>

    private void panelWithList1PropertyChange(java.beans.PropertyChangeEvent evt) {
        System.out.println("panelWithList1PropertyChange ");

    }

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /*
         * Set the Nimbus look and feel
         */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /*
         * If Nimbus (introduced in Java SE 6) is not available, stay with the
         * default look and feel. For details see
         * http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(Frame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Frame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Frame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Frame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /*
         * Create and display the form
         */
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                new Frame().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JTabbedPane jTabbedPane1;
    private dur.bounceme.net.PanelWithCombo newJPanel1;
    private dur.bounceme.net.PanelWithList panelWithList1;
    private dur.bounceme.net.PanelWithTable panelWithTable1;
    // End of variables declaration
}

The key being that panelWithList1PropertyChange is the listener on 'panelWithList' itself.

Because PanelWithList.firePropertyChange("list", -1, 1); cannot send Object nor String that I see, I'm not exactly sure how to get the value selected all the way from the JList up to the JFrame.

Hmm, well the API says yes it can send Objects. Have to check that out.

I think it's necessary to get some info about the model which the JList is using up to the JFrame. However, doesn't that break MVC? Or maybe that's the wrong approach.