/*
* 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.
*/

/**
* This class provides a node of a linked list that contains owe node
* for each step of the simulation.
* format.
*
* @author  Bill Venners
*/
class StepNode {

    private String theString;
    private StepNode next;
    private StepNode prev;
    private boolean nextValid = false;
    private boolean prevValid = false;
    private int byteCount = 0;

    StepNode(String s, int bytes) {
        theString = s;
        byteCount = bytes;
    }

    String getString() {
        return theString;
    }

    int getByteCount() {
        return byteCount;
    }

    StepNode getNext() {
        // Should probably throw an exception here if !nextValid
        return next;
    }

    void setNext(StepNode n) {
        next = n;
        nextValid = true;
    }

    boolean last() {
        return !nextValid;
    }

    StepNode getPrev() {
        // Should probably throw an exception here if !prevValid
        return prev;
    }

    void setPrev(StepNode n) {
        prev = n;
        prevValid = true;
    }

    boolean first() {
        return !prevValid;
    }
}