//: c11:Blips.java
// From 'Thinking in Java, 2nd ed.' by Bruce Eckel
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
// Simple use of Externalizable & a pitfall.
import java.io.*;
import java.util.*;

class Blip1 implements Externalizable {
  public Blip1() {
    System.out.println("Blip1 Constructor");
  }
  public void writeExternal(ObjectOutput out)
      throws IOException {
    System.out.println("Blip1.writeExternal");
  }
  public void readExternal(ObjectInput in)
     throws IOException, ClassNotFoundException {
    System.out.println("Blip1.readExternal");
  }
}

class Blip2 implements Externalizable {
  Blip2() {
    System.out.println("Blip2 Constructor");
  }
  public void writeExternal(ObjectOutput out)
      throws IOException {
    System.out.println("Blip2.writeExternal");
  }
  public void readExternal(ObjectInput in)
     throws IOException, ClassNotFoundException {
    System.out.println("Blip2.readExternal");
  }
}

public class Blips {
  // Throw exceptions to console:
  public static void main(String[] args) 
  throws IOException, ClassNotFoundException {
    System.out.println("Constructing objects:");
    Blip1 b1 = new Blip1();
    Blip2 b2 = new Blip2();
    ObjectOutputStream o =
      new ObjectOutputStream(
        new FileOutputStream("Blips.out"));
    System.out.println("Saving objects:");
    o.writeObject(b1);
    o.writeObject(b2);
    o.close();
    // Now get them back:
    ObjectInputStream in =
      new ObjectInputStream(
        new FileInputStream("Blips.out"));
    System.out.println("Recovering b1:");
    b1 = (Blip1)in.readObject();
    // OOPS! Throws an exception:
//! System.out.println("Recovering b2:");
//! b2 = (Blip2)in.readObject();
  }
} ///:~