/* * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * *   - Redistributions of source code must retain the above copyright *     notice, this list of conditions and the following disclaimer. * *   - Redistributions in binary form must reproduce the above copyright *     notice, this list of conditions and the following disclaimer in the *     documentation and/or other materials provided with the distribution. * *   - Neither the name of Sun Microsystems nor the names of its *     contributors may be used to endorse or promote products derived *     from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package events;/* * ContainerEventDemo.java requires no other files. */import javax.swing.*;import java.awt.Dimension;import java.awt.GridLayout;import java.awt.GridBagLayout;import java.awt.GridBagConstraints;import java.awt.event.ContainerEvent;import java.awt.event.ContainerListener;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.util.Vector;public class ContainerEventDemo extends JPanel                                 implements ContainerListener,                                           ActionListener {    JTextArea display;    JPanel buttonPanel;    JButton addButton, removeButton, clearButton;    Vector<JButton> buttonList;    static final String ADD = "add";    static final String REMOVE = "remove";    static final String CLEAR = "clear";    static final String newline = "\n";    public ContainerEventDemo() {        super(new GridBagLayout());        GridBagLayout gridbag = (GridBagLayout)getLayout();        GridBagConstraints c = new GridBagConstraints();        //Initialize an empty list of buttons.        buttonList = new Vector<JButton>(10, 10);        //Create all the components.        addButton = new JButton("Add a button");        addButton.setActionCommand(ADD);        addButton.addActionListener(this);        removeButton = new JButton("Remove a button");        removeButton.setActionCommand(REMOVE);        removeButton.addActionListener(this);        buttonPanel = new JPanel(new GridLayout(1,1));        buttonPanel.setPreferredSize(new Dimension(200, 75));        buttonPanel.addContainerListener(this);        display = new JTextArea();        display.setEditable(false);        JScrollPane scrollPane = new JScrollPane(display);        scrollPane.setPreferredSize(new Dimension(200, 75));        clearButton = new JButton("Clear text area");        clearButton.setActionCommand(CLEAR);        clearButton.addActionListener(this);        c.fill = GridBagConstraints.BOTH; //Fill entire cell.        c.weighty = 1.0;  //Button area and message area have equal height.        c.gridwidth = GridBagConstraints.REMAINDER; //end of row        gridbag.setConstraints(scrollPane, c);        add(scrollPane);        c.weighty = 0.0;          gridbag.setConstraints(clearButton, c);        add(clearButton);        c.weightx = 1.0;  //Add/remove buttons have equal width.        c.gridwidth = 1;  //NOT end of row        gridbag.setConstraints(addButton, c);        add(addButton);        c.gridwidth = GridBagConstraints.REMAINDER; //end of row        gridbag.setConstraints(removeButton, c);        add(removeButton);        c.weighty = 1.0;  //Button area and message area have equal height.        gridbag.setConstraints(buttonPanel, c);        add(buttonPanel);        setPreferredSize(new Dimension(400, 400));        setBorder(BorderFactory.createEmptyBorder(20,20,20,20));    }    public void componentAdded(ContainerEvent e) {        displayMessage(" added to ", e);    }    public void componentRemoved(ContainerEvent e) {        displayMessage(" removed from ", e);    }    void displayMessage(String action, ContainerEvent e) {        display.append(((JButton)e.getChild()).getText()                       + " was"                       + action                       + e.getContainer().getClass().getName()                       + newline);        display.setCaretPosition(display.getDocument().getLength());    }    /*     * This could have been implemented as two or three     * classes or objects, for clarity.     */    public void actionPerformed(ActionEvent e) {        String command = e.getActionCommand();        if (ADD.equals(command)) {            JButton newButton = new JButton("JButton #"                                          + (buttonList.size() + 1));            buttonList.addElement(newButton);            buttonPanel.add(newButton);            buttonPanel.revalidate(); //Make the button show up.        } else if (REMOVE.equals(command)) {            int lastIndex = buttonList.size() - 1;            try {                JButton nixedButton = buttonList.elementAt(lastIndex);                buttonPanel.remove(nixedButton);                buttonList.removeElementAt(lastIndex);                buttonPanel.revalidate(); //Make the button disappear.                buttonPanel.repaint(); //Make the button disappear.            } catch (ArrayIndexOutOfBoundsException exc) {}        } else if (CLEAR.equals(command)) {            display.setText("");        }    }    /**     * Create the GUI and show it.  For thread safety,     * this method should be invoked from the     * event-dispatching thread.     */    private static void createAndShowGUI() {        //Create and set up the window.        JFrame frame = new JFrame("ContainerEventDemo");        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        //Create and set up the content pane.        JComponent newContentPane = new ContainerEventDemo();        newContentPane.setOpaque(true); //content panes must be opaque        frame.setContentPane(newContentPane);        //Display the window.        frame.pack();        frame.setVisible(true);    }    public static void main(String[] args) {        //Schedule a job for the event-dispatching thread:        //creating and showing this application's GUI.        javax.swing.SwingUtilities.invokeLater(new Runnable() {            public void run() {                createAndShowGUI();            }        });    }}