arctest.java

一个小公司要求给写的很简单的任务管理系统。

/*
 * @(#)ArcTest.java	1.16 06/02/22
 * 
 * Copyright (c) 2006 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:
 * 
 * -Redistribution of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 * 
 * -Redistribution 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, Inc. or the names of contributors may 
 * be used to endorse or promote products derived from this software without 
 * specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL 
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST 
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, 
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY 
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, 
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility.
 */

/*
 * @(#)ArcTest.java	1.16 06/02/22
 */

import java.awt.*;
import java.awt.event.*;
import java.applet.*;

/**
 * An interactive test of the Graphics.drawArc and Graphics.fillArc
 * routines. Can be run either as a standalone application by
 * typing "java ArcTest" or as an applet in the AppletViewer.
 */
public class ArcTest extends Applet {
    ArcControls controls;   // The controls for marking and filling arcs
    ArcCanvas canvas;       // The drawing area to display arcs

    public void init() {
	setLayout(new BorderLayout());
	canvas = new ArcCanvas();
	add("Center", canvas);
	add("South", controls = new ArcControls(canvas));
    }

    public void destroy() {
        remove(controls);
        remove(canvas);
    }

    public void start() {
	controls.setEnabled(true);
    }

    public void stop() {
	controls.setEnabled(false);
    }

    public void processEvent(AWTEvent e) {
        if (e.getID() == Event.WINDOW_DESTROY) {
            System.exit(0);
        }
    }

    public static void main(String args[]) {
	Frame f = new Frame("ArcTest");
	ArcTest	arcTest = new ArcTest();

	arcTest.init();
	arcTest.start();

	f.add("Center", arcTest);
	f.setSize(300, 300);
	f.show();
    }

    public String getAppletInfo() {
        return "An interactive test of the Graphics.drawArc and \nGraphics.fillArc routines. Can be run \neither as a standalone application by typing 'java ArcTest' \nor as an applet in the AppletViewer.";
    }
}

class ArcCanvas extends Canvas {
    int		startAngle = 0;
    int		extent = 45;
    boolean	filled = false;
    Font	font = new java.awt.Font("SansSerif", Font.PLAIN, 12);

    public void paint(Graphics g) {
	Rectangle r = getBounds();
	int hlines = r.height / 10;
	int vlines = r.width / 10;

	g.setColor(Color.pink);
	for (int i = 1; i <= hlines; i++) {
	    g.drawLine(0, i * 10, r.width, i * 10);
	}
	for (int i = 1; i <= vlines; i++) {
	    g.drawLine(i * 10, 0, i * 10, r.height);
	}

	g.setColor(Color.red);
	if (filled) {
	    g.fillArc(0, 0, r.width - 1, r.height - 1, startAngle, extent);
	} else {
	    g.drawArc(0, 0, r.width - 1, r.height - 1, startAngle, extent);
	}

	g.setColor(Color.black);
	g.setFont(font);
	g.drawLine(0, r.height / 2, r.width, r.height / 2);
	g.drawLine(r.width / 2, 0, r.width / 2, r.height);
	g.drawLine(0, 0, r.width, r.height);
	g.drawLine(r.width, 0, 0, r.height);
	int sx = 10;
	int sy = r.height - 28;
	g.drawString("Start = " + startAngle, sx, sy);
	g.drawString("Extent = " + extent, sx, sy + 14);
    }

    public void redraw(boolean filled, int start, int extent) {
	this.filled = filled;
	this.startAngle = start;
	this.extent = extent;
	repaint();
    }
}

class ArcControls extends Panel
                  implements ActionListener {
    TextField startTF;
    TextField extentTF;
    ArcCanvas canvas;

    public ArcControls(ArcCanvas canvas) {
	Button b = null;

	this.canvas = canvas;
	add(startTF = new IntegerTextField("0", 4));
	add(extentTF = new IntegerTextField("45", 4));
	b = new Button("Fill");
	b.addActionListener(this);
	add(b);
	b = new Button("Draw");
	b.addActionListener(this);
	add(b);
    }

    public void actionPerformed(ActionEvent ev) {
	String label = ev.getActionCommand();

        int start, extent; 
        try {
            start = Integer.parseInt(startTF.getText().trim());
        } catch (NumberFormatException nfe) {
            start = 0;
        }
        try {
            extent = Integer.parseInt(extentTF.getText().trim());
        } catch (NumberFormatException nfe) {
            extent = 0;
        }

	canvas.redraw(label.equals("Fill"), start, extent);
    }
}

class IntegerTextField extends TextField {

    String oldText = null;

    public IntegerTextField(String text, int columns) {
        super(text, columns);
        enableEvents(AWTEvent.KEY_EVENT_MASK | AWTEvent.TEXT_EVENT_MASK);
        oldText = getText();
    }

    // Consume non-digit KeyTyped events
    // Note that processTextEvent kind of eliminates the need for this
    // function, but this is neater, since ideally, it would prevent
    // the text from appearing at all.  Sigh.  See bugid 4100317/4114565.
    //
    protected void processEvent(AWTEvent evt) {
        int id = evt.getID();
        if (id != KeyEvent.KEY_TYPED) {
            super.processEvent(evt);
            return;
        }

        KeyEvent kevt = (KeyEvent) evt;
        char c = kevt.getKeyChar();

        // Digits, backspace, and delete are okay
        // Note that the minus sign is allowed, but not the decimal
        if (Character.isDigit(c) || (c == '\b') || (c == '\u007f') || 
            (c == '\u002d')) {
            super.processEvent(evt);
            return;
        }

        Toolkit.getDefaultToolkit().beep();
        kevt.consume();
    }

    // Should consume TextEvents for non-integer Strings
    // Store away the text in the tf for every TextEvent
    // so we can revert to it on a TextEvent (paste, or 
    // legal key in the wrong location) with bad text
    //
    protected void processTextEvent(TextEvent te) {
        // The empty string is okay, too
        String newText = getText();
        if (newText.equals("") || textIsInteger(newText)) {
            oldText = newText;
            super.processTextEvent(te);
            return;
        }

        Toolkit.getDefaultToolkit().beep();
        setText(oldText);
    }

    // Returns true for Integers (zero and negative 
    // values are allowed).
    // Note that the empty string is not allowed. 
    // 
    private boolean textIsInteger(String textToCheck) {
        int value = -1;

        try {
            value = Integer.parseInt(textToCheck, 10);
            return true;
        } catch (NumberFormatException nfe) {
            return false;
        }
    }
}