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Blip3.javaAPI DocExample3995Mon Apr 06 18:10:24 BST 1998None

Blip3.java

//: Blip3.java
//////////////////////////////////////////////////
// Copyright (c) Bruce Eckel, 1998
// Source code file from the book "Thinking in Java"
// All rights reserved EXCEPT as allowed by the
// following statements: You can freely use this file
// for your own work (personal or commercial),
// including modifications and distribution in
// executable form only. Permission is granted to use
// this file in classroom situations, including its
// use in presentation materials, as long as the book
// "Thinking in Java" is cited as the source. 
// Except in classroom situations, you cannot copy
// and distribute this code; instead, the sole
// distribution point is http://www.BruceEckel.com 
// (and official mirror sites) where it is
// freely available. You cannot remove this
// copyright and notice. You cannot distribute
// modified versions of the source code in this
// package. You cannot use this file in printed
// media without the express permission of the
// author. Bruce Eckel makes no representation about
// the suitability of this software for any purpose.
// It is provided "as is" without express or implied
// warranty of any kind, including any implied
// warranty of merchantability, fitness for a
// particular purpose or non-infringement. The entire
// risk as to the quality and performance of the
// software is with you. Bruce Eckel and the
// publisher shall not be liable for any damages
// suffered by you or any third party as a result of
// using or distributing software. In no event will
// Bruce Eckel or the publisher 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 Bruce Eckel
// and the publisher have been advised of the
// possibility of such damages. Should the software
// prove defective, you assume the cost of all
// necessary servicing, repair, or correction. If you
// think you've found an error, please email all
// modified files with clearly commented changes to:
// Bruce@EckelObjects.com. (Please use the same
// address for non-code errors found in the book.)
/////////////////////////////////////////////////

// Reconstructing an externalizable object
import java.io.*;
import java.util.*;

class Blip3 implements Externalizable {
  int i;
  String s; // No initialization
  public Blip3() {
    System.out.println("Blip3 Constructor");
    // s, i not initialized
  }
  public Blip3(String x, int a) {
    System.out.println("Blip3(String x, int a)");
    s = x;
    i = a;
    // s & i initialized only in non-default
    // constructor.
  }
  public String toString() { return s + i; }
  public void writeExternal(ObjectOutput out)
      throws IOException {
    System.out.println("Blip3.writeExternal");
    // You must do this:
    out.writeObject(s); out.writeInt(i);
  }
  public void readExternal(ObjectInput in)
     throws IOException, ClassNotFoundException {
    System.out.println("Blip3.readExternal");
    // You must do this:
    s = (String)in.readObject(); 
    i =in.readInt();
  }
  public static void main(String[] args) {
    System.out.println("Constructing objects:");
    Blip3 b3 = new Blip3("A String ", 47);
    System.out.println(b3.toString());
    try {
      ObjectOutputStream o =
        new ObjectOutputStream(
          new FileOutputStream("Blip3.out"));
      System.out.println("Saving object:");
      o.writeObject(b3);
      o.close();
      // Now get it back:
      ObjectInputStream in =
        new ObjectInputStream(
          new FileInputStream("Blip3.out"));
      System.out.println("Recovering b3:");
      b3 = (Blip3)in.readObject();
      System.out.println(b3.toString());
    } catch(Exception e) {
      e.printStackTrace();
    }
  }
} ///:~