/*
* @(#)Book.java 1.1 98/10/03
*
* 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.
*
* @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" );
}
}
|