/* * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved. * * Redistribution and use in source and binary forms, with or * without modification, are permitted provided that the following * conditions are met: * * -Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * -Redistribution in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * Neither the name of Oracle nor the names of * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * This software is provided "AS IS," without a warranty of any * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY * EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY * DAMAGES OR LIABILITIES SUFFERED BY LICENSEE AS A RESULT OF OR * RELATING TO USE, MODIFICATION OR DISTRIBUTION OF THE SOFTWARE OR * ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE * FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, * SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF * THE USE OF OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN * ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. * * You acknowledge that Software is not designed, licensed or * intended for use in the design, construction, operation or * maintenance of any nuclear facility. */ 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. * * @serialData Saves state of its superclass by * calling its writeExternal method and * then save its own fields. Writes numpages field as int, * name field as an object and ishardcover field as a boolean. * * @see ReadingMaterial#writeExternal(ObjectOutput) */ 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 class'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" ); } }