Java example source code file (NervousText.java)

This example Java source code file (NervousText.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

awt, daniel, event, font, hotjava, override, regular_ht, regular_wd, serif, small_ht, small_wd, stringbuilder, text, the, thread, true

The NervousText.java Java example source code

/*
 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. 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 Oracle 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.
 */

/*
 * This source code is provided to illustrate the usage of a given feature
 * or technique and has been deliberately simplified. Additional steps
 * required for a production-quality application, such as security checks,
 * input validation and proper error handling, might not be present in
 * this sample code.
 */



import java.awt.Graphics;
import java.awt.Font;
import java.applet.Applet;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;


/**
 * An applet that displays jittering text on the screen.
 *
 * @author Daniel Wyszynski 04/12/95
 * @author 05/09/95 kwalrath Changed string; added thread suspension
 * @author 02/06/98 madbot removed use of suspend and resume and cleaned up
 */
@SuppressWarnings("serial")
public class NervousText extends Applet implements Runnable, MouseListener {

    String banner;              // The text to be displayed
    char bannerChars[];         // The same text as an array of characters
    char attributes[];          // Character attributes ('^' for superscript)
    Thread runner = null;       // The thread that is displaying the text
    boolean threadSuspended;    // True when thread suspended (via mouse click)
    static final int REGULAR_WD = 15;
    static final int REGULAR_HT = 36;
    static final int SMALL_WD = 12;
    static final int SMALL_HT = 24;
    Font regularFont = new Font("Serif", Font.BOLD, REGULAR_HT);
    Font smallFont = new Font("Serif", Font.BOLD, SMALL_HT);

    @Override
    public void init() {
        banner = getParameter("text");
        if (banner == null) {
            banner = "HotJava";
        }

        int bannerLength = banner.length();
        StringBuilder bc = new StringBuilder(bannerLength);
        StringBuilder attrs = new StringBuilder(bannerLength);
        int wd = 0;
        for (int i = 0; i < bannerLength; i++) {
            char c = banner.charAt(i);
            char a = 0;
            if (c == '^') {
                i++;
                if (i < bannerLength) {
                    c = banner.charAt(i);
                    a = '^';
                    wd += SMALL_WD - REGULAR_WD;
                } else {
                    break;
                }
            }
            bc.append(c);
            attrs.append(a);
            wd += REGULAR_WD;
        }

        bannerLength = bc.length();
        bannerChars = new char[bannerLength];
        attributes = new char[bannerLength];
        bc.getChars(0, bannerLength, bannerChars, 0);
        attrs.getChars(0, bannerLength, attributes, 0);

        threadSuspended = false;
        resize(wd + 10, 50);
        addMouseListener(this);
    }

    @Override
    public void destroy() {
        removeMouseListener(this);
    }

    @Override
    public void start() {
        runner = new Thread(this);
        runner.start();
    }

    @Override
    public synchronized void stop() {
        runner = null;
        if (threadSuspended) {
            threadSuspended = false;
            notify();
        }
    }

    @Override
    public void run() {
        Thread me = Thread.currentThread();
        while (runner == me) {
            try {
                Thread.sleep(100);
                synchronized (this) {
                    while (threadSuspended) {
                        wait();
                    }
                }
            } catch (InterruptedException e) {
            }
            repaint();
        }
    }

    @Override
    public void paint(Graphics g) {
        int length = bannerChars.length;
        for (int i = 0, x = 0; i < length; i++) {
            int wd, ht;
            if (attributes[i] == '^') {
                wd = SMALL_WD;
                ht = SMALL_HT;
                g.setFont(smallFont);
            } else {
                wd = REGULAR_WD;
                ht = REGULAR_HT;
                g.setFont(regularFont);
            }
            int px = (int) (10 * Math.random() + x);
            int py = (int) (10 * Math.random() + ht);
            g.drawChars(bannerChars, i, 1, px, py);
            x += wd;
        }
    }

    @Override
    public synchronized void mousePressed(MouseEvent e) {
        e.consume();
        threadSuspended = !threadSuspended;
        if (!threadSuspended) {
            notify();
        }
    }

    @Override
    public void mouseReleased(MouseEvent e) {
    }

    @Override
    public void mouseEntered(MouseEvent e) {
    }

    @Override
    public void mouseExited(MouseEvent e) {
    }

    @Override
    public void mouseClicked(MouseEvent e) {
    }

    @Override
    public String getAppletInfo() {
        return "Title: NervousText\nAuthor: Daniel Wyszynski\n"
                + "Displays a text banner that jitters.";
    }

    @Override
    public String[][] getParameterInfo() {
        String pinfo[][] = {
            { "text", "string", "Text to display" }, };
        return pinfo;
    }
}