/*
 * @(#)Book.java	1.1 97/12/12        
 *
 * Copyright (c) 1997 Sun Microsystems, Inc. All Rights Reserved.
 *
 * This software is the confidential and proprietary information of Sun
 * Microsystems, Inc. ("Confidential Information").  You shall not
 * disclose such Confidential Information and shall use it only in
 * accordance with the terms of the license agreement you entered into
 * with Sun.
 *
 * SUN 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 A PARTICULAR
 * PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR ANY DAMAGES
 * SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING
 * THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * 
 */

import java.io.*;


/**
 * The Externalizable subclass.
 * Will save the state of its superclass by calling the superclass's 
 * writeExternal and readExternal Methods from within its own writeExternal 
 * and readExternal methods
 */
public class Book extends ReadingMaterial implements Externalizable {

    private int numpages;
    private String name;
    private boolean ishardcover;

    // other relevant information and methods
    // .
    // .
    // .
   
    /** 
     * mandatory public no-arg constructor 
     */
    public Book() { 
	super(); }
  
    public Book(int pages, String n, boolean hardcover, String author,
	 String subject, int yearwritten) {

	super(author, subject, yearwritten);
	numpages = pages;
	name = n;
	ishardcover = hardcover;
    }

    /**
     * Mandatory writeExternal method. Will save the state of its superclass by
     * calling its writeExternal method and then save its own fields.
     */
    public void writeExternal(ObjectOutput out) throws IOException {
	
	// first we call the writeExternal of the superclass as to write
	// all the superclass data fields
	super.writeExternal(out);

	// now we take care of this subclass's fields
	out.writeInt(numpages);
	out.writeObject(name);
	out.writeBoolean(ishardcover);
    }

    /**
     * Mandatory readExternal method. Will read in the data that we wrote out
     * in the writeExternal method. Restores the state of the superclass 
     * first by calling the superclass's readExternal method. Then, restores 
     * its own fields. These fields MUST BE IN THE SAME ORDER AND TYPE as we
     * wrote them out.
     * By the time, readExternal is called, an object of this class has already
     * been created using the public no-arg constructor, so this method is
     * used to restore the data to all of the fields of the newly created
     * object.
     */
    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {

      // first call the superclass external method
    super.readExternal(in);
    
    // now take care of this subclass's fields
    numpages = in.readInt();
    name = (String)in.readObject();
    ishardcover= in.readBoolean();
  }

    /** 
     * Prints out the fields. used for testing!
     */
    public String toString() {
        return("Name: " + name + "\n" + "Author: " + super.getAuthor() + "\n" + "Pages: "
+ numpages + "\n" + "Subject: " + super.getSubject() + "\n" + "Year: " + super.getYearwritten() + "\n" );
    }
}