Tomcat example source code file (Clock2.java)

This example Tomcat source code file (Clock2.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

awt, color, color, date, default, e, font, rgb, simpledateformat, simpledateformat, string, string, text, the, the, thread, util

The Tomcat Clock2.java source code

/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

import java.util.*;
import java.awt.*;
import java.applet.*;
import java.text.*;

/**
 * Time!
 *
 * @author Rachel Gollub
 */

public class Clock2 extends Applet implements Runnable {
    Thread timer;                // The thread that displays clock
    int lastxs, lastys, lastxm,
        lastym, lastxh, lastyh;  // Dimensions used to draw hands 
    SimpleDateFormat formatter;  // Formats the date displayed
    String lastdate;             // String to hold date displayed
    Font clockFaceFont;          // Font for number display on clock
    Date currentDate;            // Used to get date to display
    Color handColor;             // Color of main hands and dial
    Color numberColor;           // Color of second hand and numbers

    public void init() {
        int x,y;
        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 (Exception E) { }
        try {
            handColor = new Color(Integer.parseInt(getParameter("fgcolor1"),16));
        } catch (Exception E) { }
        try {
            numberColor = new Color(Integer.parseInt(getParameter("fgcolor2"),16));
        } catch (Exception E) { }
        resize(300,300);              // Set clock window size
    }

    // Plotpoints allows calculation to only cover 45 degrees of the circle,
    // and then mirror
    public void plotpoints(int x0, int y0, int x, int y, Graphics g) {
        g.drawLine(x0+x,y0+y,x0+x,y0+y);
        g.drawLine(x0+y,y0+x,x0+y,y0+x);
        g.drawLine(x0+y,y0-x,x0+y,y0-x);
        g.drawLine(x0+x,y0-y,x0+x,y0-y);
        g.drawLine(x0-x,y0-y,x0-x,y0-y);
        g.drawLine(x0-y,y0-x,x0-y,y0-x);
        g.drawLine(x0-y,y0+x,x0-y,y0+x);
        g.drawLine(x0-x,y0+y,x0-x,y0+y);
    }

    // Circle is just Bresenham's algorithm for a scan converted circle
    public void circle(int x0, int y0, int r, Graphics g) {
        int x,y;
        float d;
        x=0;
        y=r;
        d=5/4-r;
        plotpoints(x0,y0,x,y,g);

        while (y>x){
            if (d<0) {
                d=d+2*x+3;
                x++;
            }
            else {
                d=d+2*(x-y)+5;
                x++;
                y--;
            }
            plotpoints(x0,y0,x,y,g);
        }
    }

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

        currentDate = new Date();
        SimpleDateFormat formatter = new SimpleDateFormat("s",Locale.getDefault());
        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;
        }
        formatter.applyPattern("EEE MMM dd HH:mm:ss yyyy");
        today = formatter.format(currentDate);
        xcenter=80;
        ycenter=55;
    
    // a= s* pi/2 - pi/2 (to switch 0,0 from 3:00 to 12:00)
    // x = r(cos a) + xcenter, y = r(sin a) + ycenter
    
        xs = (int)(Math.cos(s * 3.14f/30 - 3.14f/2) * 45 + xcenter);
        ys = (int)(Math.sin(s * 3.14f/30 - 3.14f/2) * 45 + ycenter);
        xm = (int)(Math.cos(m * 3.14f/30 - 3.14f/2) * 40 + xcenter);
        ym = (int)(Math.sin(m * 3.14f/30 - 3.14f/2) * 40 + ycenter);
        xh = (int)(Math.cos((h*30 + m/2) * 3.14f/180 - 3.14f/2) * 30 + xcenter);
        yh = (int)(Math.sin((h*30 + m/2) * 3.14f/180 - 3.14f/2) * 30 + ycenter);
    
    // Draw the circle and numbers
    
        g.setFont(clockFaceFont);
        g.setColor(handColor);
        circle(xcenter,ycenter,50,g);
        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);

    // Erase if necessary, and redraw
    
        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); }
        g.setColor(numberColor);
        g.drawString("", 5, 125);
        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;
    }

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

    public void stop() {
        timer = null;
    }

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

    public void update(Graphics g) {
        paint(g);
    }

    public String getAppletInfo() {
        return "Title: A Clock \nAuthor: Rachel Gollub, 1995 \nAn analog clock.";
    }
  
    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 seconds hand and numbers. Default is dark gray."}
        };
        return info;
    }
}