book.java

JavaTM 2 SDK, Standard Edition Documentation

/*
 * Copyright 2002 Sun Microsystems, Inc. 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 Sun Microsystems, Inc. or 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 
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 * 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.*;
 
class Book extends ReadingMaterial implements Serializable {

    int numpages;
    String name;
    boolean ishardcover;

    // other relevant information and methods
    // .
    // .
    // .

    Book(int pages, String n, boolean hardcover, String author,
	 String subject, int yearwritten) 
    {
	super(author, subject, yearwritten);
	numpages = pages;
	name = n;
	ishardcover = hardcover;
    }

    /**
     * Saves its own fields by calling defaultWriteObject and then explicitly
     * saves the fields of its supertype  
     * 
     * @serialData Store own serializable fields by calling defaultWriteObject
     *             and save supertype fields as optional data. Optional
     *             data is written in following sequence; author field 
     *             is written as object, subject is an object and the
     *             yearwritten field is written as an integer.
     */
    private void writeObject(ObjectOutputStream out)  throws IOException {
        
	// Take care of this class's field first by calling defaultWriteObject
	out.defaultWriteObject();
	
	/*
	 * Since the superclass does not implement the Serializable interface
	 * we explicitly do the saving... Since these fields are not private
	 * we can access them directly. If they were private, the superclass
	 * would have to implement get and set methods that would allow the
	 * subclass this necessary access for proper saving.
	 */
	out.writeObject(author);
	out.writeObject(subject);
	out.writeInt(yearwritten);
    }

    /**
     * Restores its own fields by calling defaultReadObject and then explicitly
     * restores the fields of its supertype. 
     */
    private void readObject(ObjectInputStream in) 
	throws IOException, ClassNotFoundException {
    
	    /*
	     * Take care of this class's fields first by calling 
	     * defaultReadObject
	     */
	    in.defaultReadObject();
    
	    /* 
	     * Since the superclass does not implement the Serializable 
	     * interface we explicitly do the restoring... Since these fields 
	     * are not private we can access them directly. If they were 
	     * private, the superclass would have to implement get and set 
	     * methods that would allow the subclass this necessary access 
	     * for proper saving or restoring.
	     */
	    author = (String) in.readObject();
	    subject = (String) in.readObject();
	    yearwritten = in.readInt();
    }

    /** Print out the field values. Useful for testing.
     */
   public String toString() {
	return("Name: " + name + "\n" + "Author: " + author + "\n" + "Pages: "
	       + numpages + "\n" + "Subject: " + subject + "\n" + "Year: " + yearwritten
	       + "\n");
    }
}