/** 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 words on the operand stack.** @author  Bill Venners*/class OperandStackPanel extends Panel {    private int memoryLocationsVisibleCount;    private Label[] pointer;    private Label[] address;    private Label[] wordValue;    private Label[] logicalValue;    private int currentOptopRow;    private ColoredLabel optopRegister;    OperandStackPanel(int maxStack) {        // Add one to maxStack so that "optop>" has somewhere to go        // when the stack is full.        memoryLocationsVisibleCount = maxStack + 1;        pointer = new Label[memoryLocationsVisibleCount];        address = new Label[memoryLocationsVisibleCount];        wordValue = new Label[memoryLocationsVisibleCount];        logicalValue = new Label[memoryLocationsVisibleCount];        // Initialize the title        Label title = new Label(StringTable.operandStack, Label.CENTER);        title.setFont(new Font("Helvetica", Font.BOLD, 11));        // Initialize the labelled pc register panel        Panel registerPanel = new Panel();        registerPanel.setLayout(new BorderLayout(5,5));        optopRegister = new ColoredLabel("0000", Label.CENTER, Color.lightGray);        optopRegister.setFont(new Font("TimesRoman", Font.PLAIN, 11));        Label pcRegTitle = new Label(StringTable.optop, Label.RIGHT);        pcRegTitle.setFont(new Font("Helvetica", Font.ITALIC, 11));        registerPanel.add("East", optopRegister);        registerPanel.add("Center", pcRegTitle);        // 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.hexValue, Label.CENTER));        columnTitles.add(new Label(StringTable.value, 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]);            wordValue[i] = new Label("", Label.CENTER);            methodView.add(wordValue[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);    }    public void updateView(int optop, Object[] operandStack) {        // Assume length of array is one less that memoryLocationsVisibleCount,        // which should equal maxStack + 1.        int len = operandStack.length;        for (int i = 0; i < len; ++i) {            address[i].setText(Integer.toString(i));            Object locVar = operandStack[i];            if (locVar == null) {                wordValue[i].setText("");                logicalValue[i].setText("");            }            else if (locVar instanceof Integer) {                Integer value = (Integer) locVar;                HexString wordValueHexString = new HexString(value.intValue(), 8);                wordValue[i].setText(wordValueHexString.getString());                logicalValue[i].setText(value.toString());            }            else if (locVar instanceof Float) {                Float wrapperVal = (Float) locVar;                float fVal = wrapperVal.floatValue();                int floatBits = Float.floatToIntBits(fVal);                HexString wordValueHexString = new HexString(floatBits, 8);                wordValue[i].setText(wordValueHexString.getString());                logicalValue[i].setText(wrapperVal.toString());            }            else if (locVar instanceof Long) {                Long value = (Long) locVar;				long longValue = value.longValue();				int lowerWord = (int) longValue;				int upperWord = (int) (longValue >>> 32);                HexString lowerWordHexString = new HexString(lowerWord, 8);                HexString upperWordHexString = new HexString(upperWord, 8);                wordValue[i].setText(lowerWordHexString.getString());                wordValue[i + 1].setText(upperWordHexString.getString());                logicalValue[i].setText(value.toString() + "L");				++i; // must increment i twice in long case            }            else if (locVar instanceof Double) {                Double value = (Double) locVar;				double doubleValue = value.doubleValue();				long longBits = Double.doubleToLongBits(doubleValue);				int lowerWord = (int) longBits;				int upperWord = (int) (longBits >>> 32);                HexString lowerWordHexString = new HexString(lowerWord, 8);                HexString upperWordHexString = new HexString(upperWord, 8);                wordValue[i].setText(lowerWordHexString.getString());                wordValue[i + 1].setText(upperWordHexString.getString());                logicalValue[i].setText(value.toString());				++i; // must increment i twice in double case            }            else if (locVar instanceof ReturnAddress) {                ReturnAddress wrapper = (ReturnAddress) locVar;                HexString wordValueHexString = new HexString(wrapper.getReturnAddress(), 8);                wordValue[i].setText(wordValueHexString.getString());                logicalValue[i].setText("RET ADDR");            }            else {                // Its an object                wordValue[i].setText(" OBJREF ");                logicalValue[i].setText((locVar.getClass()).getName());            }        }        optopRegister.setLabelText("    " + Integer.toString(optop));        // Erase the old "optop>" pointer        pointer[currentOptopRow].setText("");        // Place the "optop>" pointer        pointer[optop].setText(StringTable.optopPointer);        currentOptopRow = optop;    }    public Insets insets() {        return new Insets(5, 5, 5, 5);    }}