/* * 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 components;import java.awt.*;import java.awt.event.*;import javax.swing.*;import javax.swing.event.*;/* ListDemo.java requires no other files. */public class ListDemo extends JPanel                      implements ListSelectionListener {    private JList list;    private DefaultListModel listModel;    private static final String hireString = "Hire";    private static final String fireString = "Fire";    private JButton fireButton;    private JTextField employeeName;    public ListDemo() {        super(new BorderLayout());        listModel = new DefaultListModel();        listModel.addElement("Debbie Scott");        listModel.addElement("Scott Hommel");        listModel.addElement("Sharon Zakhour");        //Create the list and put it in a scroll pane.        list = new JList(listModel);        list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);        list.setSelectedIndex(0);        list.addListSelectionListener(this);        list.setVisibleRowCount(5);        JScrollPane listScrollPane = new JScrollPane(list);        JButton hireButton = new JButton(hireString);        HireListener hireListener = new HireListener(hireButton);        hireButton.setActionCommand(hireString);        hireButton.addActionListener(hireListener);        hireButton.setEnabled(false);        fireButton = new JButton(fireString);        fireButton.setActionCommand(fireString);        fireButton.addActionListener(new FireListener());        employeeName = new JTextField(10);        employeeName.addActionListener(hireListener);        employeeName.getDocument().addDocumentListener(hireListener);        String name = listModel.getElementAt(                              list.getSelectedIndex()).toString();        //Create a panel that uses BoxLayout.        JPanel buttonPane = new JPanel();        buttonPane.setLayout(new BoxLayout(buttonPane,                                           BoxLayout.LINE_AXIS));        buttonPane.add(fireButton);        buttonPane.add(Box.createHorizontalStrut(5));        buttonPane.add(new JSeparator(SwingConstants.VERTICAL));        buttonPane.add(Box.createHorizontalStrut(5));        buttonPane.add(employeeName);        buttonPane.add(hireButton);        buttonPane.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));        add(listScrollPane, BorderLayout.CENTER);        add(buttonPane, BorderLayout.PAGE_END);    }    class FireListener implements ActionListener {        public void actionPerformed(ActionEvent e) {            //This method can be called only if            //there's a valid selection            //so go ahead and remove whatever's selected.            int index = list.getSelectedIndex();            listModel.remove(index);            int size = listModel.getSize();            if (size == 0) { //Nobody's left, disable firing.                fireButton.setEnabled(false);            } else { //Select an index.                if (index == listModel.getSize()) {                    //removed item in last position                    index--;                }                list.setSelectedIndex(index);                list.ensureIndexIsVisible(index);            }        }    }    //This listener is shared by the text field and the hire button.    class HireListener implements ActionListener, DocumentListener {        private boolean alreadyEnabled = false;        private JButton button;        public HireListener(JButton button) {            this.button = button;        }        //Required by ActionListener.        public void actionPerformed(ActionEvent e) {            String name = employeeName.getText();            //User didn't type in a unique name...            if (name.equals("") || alreadyInList(name)) {                Toolkit.getDefaultToolkit().beep();                employeeName.requestFocusInWindow();                employeeName.selectAll();                return;            }            int index = list.getSelectedIndex(); //get selected index            if (index == -1) { //no selection, so insert at beginning                index = 0;            } else {           //add after the selected item                index++;            }            listModel.insertElementAt(employeeName.getText(), index);            //If we just wanted to add to the end, we'd do this:            //listModel.addElement(employeeName.getText());            //Reset the text field.            employeeName.requestFocusInWindow();            employeeName.setText("");            //Select the new item and make it visible.            list.setSelectedIndex(index);            list.ensureIndexIsVisible(index);        }        //This method tests for string equality. You could certainly        //get more sophisticated about the algorithm.  For example,        //you might want to ignore white space and capitalization.        protected boolean alreadyInList(String name) {            return listModel.contains(name);        }        //Required by DocumentListener.        public void insertUpdate(DocumentEvent e) {            enableButton();        }        //Required by DocumentListener.        public void removeUpdate(DocumentEvent e) {            handleEmptyTextField(e);        }        //Required by DocumentListener.        public void changedUpdate(DocumentEvent e) {            if (!handleEmptyTextField(e)) {                enableButton();            }        }        private void enableButton() {            if (!alreadyEnabled) {                button.setEnabled(true);            }        }        private boolean handleEmptyTextField(DocumentEvent e) {            if (e.getDocument().getLength() <= 0) {                button.setEnabled(false);                alreadyEnabled = false;                return true;            }            return false;        }    }    //This method is required by ListSelectionListener.    public void valueChanged(ListSelectionEvent e) {        if (e.getValueIsAdjusting() == false) {            if (list.getSelectedIndex() == -1) {            //No selection, disable fire button.                fireButton.setEnabled(false);            } else {            //Selection, enable the fire button.                fireButton.setEnabled(true);            }        }    }    /**     * 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("ListDemo");        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        //Create and set up the content pane.        JComponent newContentPane = new ListDemo();        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();            }        });    }}