Re: Creating A Copy

From:
Lew <lew@nospam.lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 02 May 2007 13:54:19 -0400
Message-ID:
<kI2dnSTxN6rWTaXbnZ2dnUVZ_r-onZ2d@comcast.com>
Jason Cavett wrote:

(As for the magic bullet - serialization actually works great. The
only problem is, one of the objects in one class is not Serializable
and it's not my class, so I can't change that. Sooo...that was end of
that.)


You can still serialize the object.

Let us say you have a class Foo with a member Baz that you don't control.

public class Foo
{
   transient private Baz baz;
   ...
}

Making the Baz element transient simply means you have to manually serialize
and deserialize the Baz object. The fact that Baz is not Serializable is
moot; no one is using Baz to try. That could be complicated if Baz is a
collection itself, but let's assume it's some sort of fairly uncomplicated
class with serializable attributes.

<http://java.sun.com/javase/6/docs/api/java/io/Serializable.html>
explains to use

  private void writeObject(java.io.ObjectOutputStream out)
      throws IOException;
and

  private void readObject(java.io.ObjectInputStream in)
      throws IOException, ClassNotFoundException;

You write these methods to [de]serialize the well-known parts of Baz (untried,
untested):

  private void writeObject(java.io.ObjectOutputStream out)
      throws IOException
  {
   out.defaultWriteObject();
   out.writeObject( baz.getIntegerValue() );
   out.writeObject( baz.getStringValue() );
  }

  private void readObject(java.io.ObjectInputStream in)
      throws IOException, ClassNotFoundException
  {
   in.defaultReadObject();
   baz.setIntegerValue( (Integer) in.readObject() );
   baz.setStringValue( (String) in.readObject() );
  }

Then it matters not that Baz is not Serializable.

--
Lew

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