null.java

CmisJavaApi

/*
 * The contents of this file are subject to the Dyade Public License, 
 * as defined by the file DYADE_PUBLIC_LICENSE.TXT
 *
 * You may not use this file except in compliance with the License. You may
 * obtain a copy of the License on the Dyade web site (www.dyade.fr).
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
 * the specific terms governing rights and limitations under the License.
 *
 * The Original Code is CmisJava API, including the java package 
 * fr.dyade.cmis, released September 5, 2000.
 *
 * The Initial Developer of the Original Code is Dyade. The Original Code and
 * portions created by Dyade are Copyright Bull and Copyright INRIA. 
 * All Rights Reserved.
 */

/*      Copyright 1996-2000 by Institut National de Recherche en Informatique 
 *                             et en Automatique (INRIA)
 *          All rights reserved.  See COPYRIGHT in top-level directory.
 *
 *      Authors: Laurent Andrey, Eric Dillon, Olivier Festor
 */

//---------------------------------------------------------------------------//
//  CVS Info
//---------------------------------------------------------------------------//
//
//  $Id: Null.java,v 1.2 2000/09/05 13:30:53 festor Exp $
//  $Source: /local/resedas/CVS-Repository/CmisJavaApi/src/fr/dyade/cmis/api/types/Null.java,v $

//---------------------------------------------------------------------------//
//  Todo
//---------------------------------------------------------------------------//
//

package fr.dyade.cmis.api.types;
import java.io.ObjectStreamException;
/**
  * Java equivallent for the ASN1 Null.
  * @version $Id: Null.java,v 1.2 2000/09/05 13:30:53 festor Exp $
  */
public class Null extends Value  {
      /**
	 The unique instance for null value.
	 One instance of Null is enough per application... If the value.fEncodedValue
	 and Value.fUReasons have no meaning for a Null ASN1 value.
	 */
      public static final Null NULL= new Null();
      private Null() {
	 super(VALUE_NULL);
      }
      public String toString() {
	 return "Null";
      }
      /** Filtering instance created after deserialization.
	* <a HREF="http://www.javasoft.com/products/jdk/1.2/docs/guide/serialization/spec/input.doc6.html">
	* Read javasof doc</a> about this method. We are exactly is the example shown here:
	* "The readResolve method would be implemented to determine if that symbol was already defined 
	* and substitute the preexisting equivalent Symbol object to maintain the identity constraint...",
	* where Symbol objects is Null.NULL.
	*/
      public Object readResolve() throws ObjectStreamException {
	 return Null.NULL;
      }
} // Null