/** 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.*/package COM.artima.jvmsim;import java.awt.*;/*** This class represents that portion of the user interface* that displays the bytecodes in the method area.** @author  Bill Venners*/class MethodAreaPanel extends Panel {    private int memoryLocationsVisibleCount;    private Label[] pointer;    private Label[] address;    private Label[] byteValue;    private Label[] logicalValue;    private int[] theProgram;    private String[] theMnemonics;    private int firstVisibleRow;    private int currentProgramCounterRow;    private ColoredLabel pcRegister;    MethodAreaPanel(int memoryLocationsVisibleCount, int[] theProgram,        String[] theMnemonics) {        this.memoryLocationsVisibleCount = memoryLocationsVisibleCount;        this.theProgram = theProgram;        this.theMnemonics = theMnemonics;        pointer = new Label[memoryLocationsVisibleCount];        address = new Label[memoryLocationsVisibleCount];        byteValue = new Label[memoryLocationsVisibleCount];        logicalValue = new Label[memoryLocationsVisibleCount];        // Initialize the title        Label title = new Label(StringTable.theMethod, Label.CENTER);        title.setFont(new Font("Helvetica", Font.BOLD, 11));        // Initialize the labelled pc register panel        Panel registerPanel = new Panel();        registerPanel.setLayout(new GridLayout(1, 2, 5, 5));        pcRegister = new ColoredLabel("00000000", Label.CENTER, Color.lightGray);        pcRegister.setFont(new Font("TimesRoman", Font.PLAIN, 11));        Label pcRegTitle = new Label(StringTable.pc, Label.RIGHT);        pcRegTitle.setFont(new Font("Helvetica", Font.ITALIC, 11));        registerPanel.add(pcRegTitle);        registerPanel.add(pcRegister);        // Put the title and the pc register panel on the same panel        Panel titleRegisterPanel = new Panel();        titleRegisterPanel.setLayout(new BorderLayout());        titleRegisterPanel.add("West", registerPanel);        titleRegisterPanel.add("Center", title);        // Initialize column titles        Panel columnTitles = new Panel();        int[] hComponentCellWidths = { 2, 2, 2, 3 };        columnTitles.setLayout(new GridSnapLayout(1, 9, hComponentCellWidths));        columnTitles.setFont(new Font("Helvetica", Font.ITALIC, 11));        columnTitles.add(new Label("", Label.CENTER));        columnTitles.add(new Label(StringTable.offset, Label.CENTER));        columnTitles.add(new Label(StringTable.bytecodes, Label.CENTER));        columnTitles.add(new Label(StringTable.mnemonics, Label.LEFT));        // Initialize the 4 column view of the method        Panel methodView = new Panel();        methodView.setLayout(new GridSnapLayout(memoryLocationsVisibleCount, 9, hComponentCellWidths));        methodView.setBackground(Color.lightGray);        Font plainFont = new Font("TimesRoman", Font.PLAIN, 11);        methodView.setFont(plainFont);        Font italicFont = new Font("TimesRoman", Font.ITALIC, 11);        for (int i = 0; i < memoryLocationsVisibleCount; ++i) {            pointer[i] = new Label("", Label.RIGHT);            pointer[i].setFont(italicFont);            methodView.add(pointer[i]);            address[i] = new Label("", Label.CENTER);            methodView.add(address[i]);            byteValue[i] = new Label("", Label.CENTER);            methodView.add(byteValue[i]);            logicalValue[i] = new Label("", Label.LEFT);            methodView.add(logicalValue[i]);        }        Panel methodViewWithTitles = new Panel();        methodViewWithTitles.setLayout(new BorderLayout());        methodViewWithTitles.add("North", columnTitles);        methodViewWithTitles.add("Center", methodView);        setLayout(new BorderLayout());        add("North", titleRegisterPanel);        add("Center", methodViewWithTitles);        // Call updateView() first because updateProgramCounter() only changes        // the address, byte, and mnemonic columns if the program counter has        // moved off the page.        updateView(0);        updateProgramCounter(0);    }    // UpdateView() repaints the rightmost three columns: address, byte, and mnemonic    // starting with the passed initialaddress of theProgram.    private void updateView(int initialAddress){        int filledRowsCount = theProgram.length < memoryLocationsVisibleCount ?            theProgram.length : memoryLocationsVisibleCount;        for (int i = 0; i < filledRowsCount; ++i) {            address[i].setText(Integer.toString(initialAddress + i));            int theByte = theProgram[initialAddress + i];            HexString byteValueHexString = new HexString(theByte, 2);            byteValue[i].setText(byteValueHexString.getString());            String logicalValueStr = theMnemonics[initialAddress + i];            logicalValue[i].setText(logicalValueStr);        }    }    // Will change the pc register and pc> pointer. If necessary, will also shift    // the other three columns--address, byte, and mnemonic--by calling updateView().    public void updateProgramCounter(int newPCValue) {        // Erase the old "pc>" pointer        pointer[currentProgramCounterRow].setText("");        // Only change the address, byte, and mnemonic columns if the program        // counter has gone off the edge of the screen.        if (newPCValue - firstVisibleRow >= memoryLocationsVisibleCount) {            firstVisibleRow = newPCValue;            if (firstVisibleRow > theProgram.length - memoryLocationsVisibleCount) {                firstVisibleRow = theProgram.length - memoryLocationsVisibleCount;            }            updateView(firstVisibleRow);        }        else if (newPCValue < firstVisibleRow) {            firstVisibleRow = newPCValue;            updateView(firstVisibleRow);        }        // Place the "pc>" pointer        pointer[newPCValue - firstVisibleRow].setText(StringTable.pcPointer);        currentProgramCounterRow = newPCValue - firstVisibleRow;        // Set the program counter register        //HexString hexString = new HexString(newPCValue, 8);        pcRegister.setLabelText("    " + Integer.toString(newPCValue));    }    public Insets insets() {        return new Insets(5, 5, 5, 5);    }}