/* * 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;/** MouseWheelEventDemo.java*/import java.awt.BorderLayout;import java.awt.Color;import java.awt.Dimension;import java.awt.event.MouseWheelEvent;import java.awt.event.MouseWheelListener;import javax.swing.*;public class MouseWheelEventDemo extends JPanel        implements MouseWheelListener {    JTextArea textArea;    JScrollPane scrollPane;    static final String NEWLINE = System.getProperty("line.separator");        public static void main(String[] args) {        /* Use an appropriate Look and Feel */        try {            //UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");            //UIManager.setLookAndFeel("com.sun.java.swing.plaf.gtk.GTKLookAndFeel");            UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");        } catch (UnsupportedLookAndFeelException ex) {            ex.printStackTrace();        } catch (IllegalAccessException ex) {            ex.printStackTrace();        } catch (InstantiationException ex) {            ex.printStackTrace();        } catch (ClassNotFoundException ex) {            ex.printStackTrace();        }        /* Turn off metal's use of bold fonts */        UIManager.put("swing.boldMetal", Boolean.FALSE);                //Schedule a job for the event dispatch thread:        //creating and showing this application's GUI.        javax.swing.SwingUtilities.invokeLater(new Runnable() {            public void run() {                createAndShowGUI();            }        });    }        /**     * Create the GUI and show it.  For thread safety,     * this method should be invoked from the     * event dispatch thread.     */    private static void createAndShowGUI() {        //Create and set up the window.        JFrame frame = new JFrame("MouseWheelEventDemo");        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);                //Create and set up the content pane.        JComponent newContentPane = new MouseWheelEventDemo();        newContentPane.setOpaque(true); //content panes must be opaque        frame.setContentPane(newContentPane);                //Display the window.        frame.pack();        frame.setVisible(true);    }        public MouseWheelEventDemo() {        super(new BorderLayout());                textArea = new JTextArea();        textArea.setEditable(false);        scrollPane = new JScrollPane(textArea);        scrollPane.setVerticalScrollBarPolicy(                JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);        scrollPane.setPreferredSize(new Dimension(400, 250));        add(scrollPane, BorderLayout.CENTER);        textArea.append("This text area displays information "                + "about its mouse wheel events."                + NEWLINE);                //Register for mouse-wheel events on the text area.        textArea.addMouseWheelListener(this);                setPreferredSize(new Dimension(450, 350));        setBorder(BorderFactory.createEmptyBorder(20,20,20,20));    }        //Append to the text area and make sure the new text is visible.    void eventOutput(String eventDescription, MouseWheelEvent e) {        textArea.append(e.getComponent().getClass().getName()        + ": "                + eventDescription);        textArea.setCaretPosition(textArea.getDocument().getLength());    }        public void mouseWheelMoved(MouseWheelEvent e) {        String message;        int notches = e.getWheelRotation();        if (notches < 0) {            message = "Mouse wheel moved UP "                    + -notches + " notch(es)" + NEWLINE;        } else {            message = "Mouse wheel moved DOWN "                             + notches + " notch(es)" + NEWLINE;        }        if (e.getScrollType() == MouseWheelEvent.WHEEL_UNIT_SCROLL) {            message += "    Scroll type: WHEEL_UNIT_SCROLL" + NEWLINE;            message += "    Scroll amount: " + e.getScrollAmount()            + " unit increments per notch" + NEWLINE;            message += "    Units to scroll: " + e.getUnitsToScroll()            + " unit increments" + NEWLINE;            message += "    Vertical unit increment: "                    + scrollPane.getVerticalScrollBar().getUnitIncrement(1)                    + " pixels" + NEWLINE;        } else { //scroll type == MouseWheelEvent.WHEEL_BLOCK_SCROLL            message += "    Scroll type: WHEEL_BLOCK_SCROLL" + NEWLINE;            message += "    Vertical block increment: "                    + scrollPane.getVerticalScrollBar().getBlockIncrement(1)                    + " pixels" + NEWLINE;        }        eventOutput(message, e);    }}