Controlling Serialization By Adding Your Own WriteObject and ReadObject Methods

package com.bruceeckel;
 
//: c12:SerialCtl.java
//Controlling serialization by adding your own
//writeObject() and readObject() methods.
//From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
//www.BruceEckel.com. See copyright notice in CopyRight.txt.
 
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
 
public class SerialCtl implements Serializable {
    private String a;
 
    private transient String b;
 
    public SerialCtl(String aa, String bb) {
	a = "Not Transient: " + aa;
	b = "Transient: " + bb;
    }
 
    public String toString() {
	return a + "\n" + b;
    }
 
    private void writeObject(ObjectOutputStream stream) throws IOException {
	stream.defaultWriteObject();
	stream.writeObject(b);
    }
 
    private void readObject(ObjectInputStream stream) throws IOException,
	    ClassNotFoundException {
	stream.defaultReadObject();
	b = (String) stream.readObject();
    }
 
    public static void main(String[] args) throws IOException,
	    ClassNotFoundException {
	SerialCtl sc = new SerialCtl("Test1", "Test2");
	System.out.println("Before:\n" + sc);
	ByteArrayOutputStream buf = new ByteArrayOutputStream();
	ObjectOutputStream o = new ObjectOutputStream(buf);
	o.writeObject(sc);
	// Now get it back:
	ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(
		buf.toByteArray()));
	SerialCtl sc2 = (SerialCtl) in.readObject();
	System.out.println("After:\n" + sc2);
    }
}