/*
* Copyright (c) 1996-1999 Bill Venners. All Rights Reserved.
*
* This Java source file is part of the Interactive Illustrations Web
* Site, which is delivered in the applets directory of the CD-ROM
* that accompanies the book "Inside the Java 2 Virtual Machine" by Bill
* Venners, published by McGraw-Hill, 1999, ISBN: 0-07-135093-4. This
* source file is provided for evaluation purposes only, but you can
* redistribute it under certain conditions, described in the full
* copyright notice below.
*
* Full Copyright Notice:
*
* All the web pages and Java applets delivered in the applets
* directory of the CD-ROM, consisting of ".html," ".gif," ".class,"
* and ".java" files, are copyrighted (c) 1996-1999 by Bill
* Venners, and all rights are reserved.  This material may be copied
* and placed on any commercial or non-commercial web server on any
* network (including the internet) provided that the following
* guidelines are followed:
*
* a. All the web pages and Java Applets (".html," ".gif," ".class,"
* and ".java" files), including the source code, that are delivered
* in the applets directory of the CD-ROM that
* accompanies the book must be published together on the same web
* site.
*
* b. All the web pages and Java Applets (".html," ".gif," ".class,"
* and ".java" files) must be published "as is" and may not be altered
* in any way.
*
* c. All use and access to this web site must be free, and no fees
* can be charged to view these materials, unless express written
* permission is obtained from Bill Venners.
*
* d. The web pages and Java Applets may not be distributed on any
* media, other than a web server on a network, and may not accompany
* any book or publication.
*
* BILL VENNERS MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE
* SUITABILITY OF THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING
* BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR PARTICULAR PURPOSE, OR NON-INFRINGEMENT.  BILL VENNERS
* SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY A LICENSEE AS A
* RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
* DERIVATIVES.
*/
import java.awt.*;
import java.applet.*;

/**
* This applet simulates a compacting, mark-and-sweep
* garbage-collected heap inside a Java Virtual Machine.
*
* @author  Bill Venners
*/
public class HeapOfFish extends Applet {

    private GCHeap gcHeap = new GCHeap(15, 50);
    private LocalVariables localVars = new LocalVariables();

    private HeapOfFishControlPanel controlPanel = new HeapOfFishControlPanel();
    private HeapOfFishCanvases canvases = new HeapOfFishCanvases(gcHeap, localVars, controlPanel.getTextArea());
    private String currentHeapOfFishMode = HeapOfFishStrings.swim;

    public void init() {

        super.init();
        setBackground(Color.cyan);

        setLayout(new BorderLayout(5, 5));
        add("North", new ColoredLabel("HEAP OF FISH", Label.CENTER, Color.white));
        add("South", controlPanel);
        add("Center", canvases);
    }

    public void start() {
        canvases.start();
    }

    public void stop() {
        canvases.stop();
    }

    public Insets insets() {
        return new Insets(5, 5, 5, 5);
    }

    public boolean action(Event evt, Object arg) {
        if (evt.target instanceof Checkbox) {
            Checkbox cb = (Checkbox) evt.target;
            String cbname = cb.getLabel();
            if (cbname.equals(HeapOfFishStrings.allocateFish)) {
                if (!currentHeapOfFishMode.equals(HeapOfFishStrings.allocateFish)) {
                    controlPanel.getTextArea().setText(HeapOfFishStrings.allocateFishInstructions);
                    canvases.setMode(HeapOfFishStrings.allocateFish);
                }
            }
            else if (cbname.equals(HeapOfFishStrings.assignReferences)) {
                if (!currentHeapOfFishMode.equals(HeapOfFishStrings.assignReferences)) {
                    canvases.setMode(HeapOfFishStrings.assignReferences);
                }
            }
            else if (cbname.equals(HeapOfFishStrings.garbageCollect)) {
                if (!currentHeapOfFishMode.equals(HeapOfFishStrings.garbageCollect)) {
                    canvases.setMode(HeapOfFishStrings.garbageCollect);
                }
            }
            else if (cbname.equals(HeapOfFishStrings.compactHeap)) {
                if (!currentHeapOfFishMode.equals(HeapOfFishStrings.compactHeap)) {
                    controlPanel.getTextArea().setText(HeapOfFishStrings.compactHeapInstructions);
                    canvases.setMode(HeapOfFishStrings.compactHeap);
                }
            }
            else if (cbname.equals(HeapOfFishStrings.swim)) {
                if (!currentHeapOfFishMode.equals(HeapOfFishStrings.swim)) {
                    controlPanel.getTextArea().setText("");
                    canvases.setMode(HeapOfFishStrings.swim);
                }
            }
            currentHeapOfFishMode = cbname;
            canvases.repaint();
        }
        return true;
    }
}