Java example source code file (Clock.java)

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Java - Java tags/keywords

awt, color, date, default, font, mmm, nullpointerexception, numberformatexception, override, rgb, simpledateformat, string, suppresswarnings, text, the, thread, util

The Clock.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.applet.Applet;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;


/**
 * Time!
 *
 * @author Rachel Gollub
 * @author Daniel Peek replaced circle drawing calculation, few more changes
 */
@SuppressWarnings("serial")
public class Clock extends Applet implements Runnable {

    private volatile Thread timer;       // The thread that displays clock
    private int lastxs, lastys, lastxm,
            lastym, lastxh, lastyh;  // Dimensions used to draw hands
    private SimpleDateFormat formatter;  // Formats the date displayed
    private String lastdate;             // String to hold date displayed
    private Font clockFaceFont;          // Font for number display on clock
    private Date currentDate;            // Used to get date to display
    private Color handColor;             // Color of main hands and dial
    private Color numberColor;           // Color of second hand and numbers
    private int xcenter = 80, ycenter = 55; // Center position

    @Override
    public void init() {
        lastxs = lastys = lastxm = lastym = lastxh = lastyh = 0;
        formatter = new SimpleDateFormat("EEE MMM dd hh:mm:ss yyyy",
                Locale.getDefault());
        currentDate = new Date();
        lastdate = formatter.format(currentDate);
        clockFaceFont = new Font("Serif", Font.PLAIN, 14);
        handColor = Color.blue;
        numberColor = Color.darkGray;

        try {
            setBackground(new Color(Integer.parseInt(getParameter("bgcolor"),
                    16)));
        } catch (NullPointerException e) {
        } catch (NumberFormatException e) {
        }
        try {
            handColor = new Color(Integer.parseInt(getParameter("fgcolor1"),
                    16));
        } catch (NullPointerException e) {
        } catch (NumberFormatException e) {
        }
        try {
            numberColor = new Color(Integer.parseInt(getParameter("fgcolor2"),
                    16));
        } catch (NullPointerException e) {
        } catch (NumberFormatException e) {
        }
        resize(300, 300);              // Set clock window size
    }

    /**
     * Paint is the main part of the program
     */
    @Override
    public void update(Graphics g) {
        int xh, yh, xm, ym, xs, ys;
        int s = 0, m = 10, h = 10;
        String today;

        currentDate = new Date();

        formatter.applyPattern("s");
        try {
            s = Integer.parseInt(formatter.format(currentDate));
        } catch (NumberFormatException n) {
            s = 0;
        }
        formatter.applyPattern("m");
        try {
            m = Integer.parseInt(formatter.format(currentDate));
        } catch (NumberFormatException n) {
            m = 10;
        }
        formatter.applyPattern("h");
        try {
            h = Integer.parseInt(formatter.format(currentDate));
        } catch (NumberFormatException n) {
            h = 10;
        }

        // Set position of the ends of the hands
        xs = (int) (Math.cos(s * Math.PI / 30 - Math.PI / 2) * 45 + xcenter);
        ys = (int) (Math.sin(s * Math.PI / 30 - Math.PI / 2) * 45 + ycenter);
        xm = (int) (Math.cos(m * Math.PI / 30 - Math.PI / 2) * 40 + xcenter);
        ym = (int) (Math.sin(m * Math.PI / 30 - Math.PI / 2) * 40 + ycenter);
        xh = (int) (Math.cos((h * 30 + m / 2) * Math.PI / 180 - Math.PI / 2)
                * 30
                + xcenter);
        yh = (int) (Math.sin((h * 30 + m / 2) * Math.PI / 180 - Math.PI / 2)
                * 30
                + ycenter);

        // Get the date to print at the bottom
        formatter.applyPattern("EEE MMM dd HH:mm:ss yyyy");
        today = formatter.format(currentDate);

        g.setFont(clockFaceFont);
        // Erase if necessary
        g.setColor(getBackground());
        if (xs != lastxs || ys != lastys) {
            g.drawLine(xcenter, ycenter, lastxs, lastys);
            g.drawString(lastdate, 5, 125);
        }
        if (xm != lastxm || ym != lastym) {
            g.drawLine(xcenter, ycenter - 1, lastxm, lastym);
            g.drawLine(xcenter - 1, ycenter, lastxm, lastym);
        }
        if (xh != lastxh || yh != lastyh) {
            g.drawLine(xcenter, ycenter - 1, lastxh, lastyh);
            g.drawLine(xcenter - 1, ycenter, lastxh, lastyh);
        }

        // Draw date and hands
        g.setColor(numberColor);
        g.drawString(today, 5, 125);
        g.drawLine(xcenter, ycenter, xs, ys);
        g.setColor(handColor);
        g.drawLine(xcenter, ycenter - 1, xm, ym);
        g.drawLine(xcenter - 1, ycenter, xm, ym);
        g.drawLine(xcenter, ycenter - 1, xh, yh);
        g.drawLine(xcenter - 1, ycenter, xh, yh);
        lastxs = xs;
        lastys = ys;
        lastxm = xm;
        lastym = ym;
        lastxh = xh;
        lastyh = yh;
        lastdate = today;
        currentDate = null;
    }

    @Override
    public void paint(Graphics g) {
        g.setFont(clockFaceFont);
        // Draw the circle and numbers
        g.setColor(handColor);
        g.drawArc(xcenter - 50, ycenter - 50, 100, 100, 0, 360);
        g.setColor(numberColor);
        g.drawString("9", xcenter - 45, ycenter + 3);
        g.drawString("3", xcenter + 40, ycenter + 3);
        g.drawString("12", xcenter - 5, ycenter - 37);
        g.drawString("6", xcenter - 3, ycenter + 45);

        // Draw date and hands
        g.setColor(numberColor);
        g.drawString(lastdate, 5, 125);
        g.drawLine(xcenter, ycenter, lastxs, lastys);
        g.setColor(handColor);
        g.drawLine(xcenter, ycenter - 1, lastxm, lastym);
        g.drawLine(xcenter - 1, ycenter, lastxm, lastym);
        g.drawLine(xcenter, ycenter - 1, lastxh, lastyh);
        g.drawLine(xcenter - 1, ycenter, lastxh, lastyh);
    }

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

    @Override
    public void stop() {
        timer = null;
    }

    @Override
    @SuppressWarnings("SleepWhileHoldingLock")
    public void run() {
        Thread me = Thread.currentThread();
        while (timer == me) {
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
            }
            repaint();
        }
    }

    @Override
    public String getAppletInfo() {
        return "Title: A Clock \n"
                + "Author: Rachel Gollub, 1995 \n"
                + "An analog clock.";
    }

    @Override
    public String[][] getParameterInfo() {
        String[][] info = {
            { "bgcolor", "hexadecimal RGB number",
                "The background color. Default is the color of your browser." },
            { "fgcolor1", "hexadecimal RGB number",
                "The color of the hands and dial. Default is blue." },
            { "fgcolor2", "hexadecimal RGB number",
                "The color of the second hand and numbers. Default is dark gray." }
        };
        return info;
    }
}