class.NullNode.php

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<?php
/**
 * wCMF - wemove Content Management Framework
 * Copyright (C) 2005-2014 wemove digital solutions GmbH
 *
 * Licensed under the terms of any of the following licenses 
 * at your choice:
 *
 * - GNU Lesser General Public License (LGPL)
 *   http://www.gnu.org/licenses/lgpl.html
 * - Eclipse Public License (EPL)
 *   http://www.eclipse.org/org/documents/epl-v10.php
 *
 * See the license.txt file distributed with this work for 
 * additional information.
 *
 * $Id: class.NullNode.php 1462 2014-02-04 23:52:27Z iherwig $
 */
require_once(BASE."wcmf/lib/model/class.Node.php");

/**
 * @class NullNode
 * @ingroup Model
 * @brief NullNode is an implementation of the NullObject pattern,
 * It inherits all functionality from Node (acts like a Node)
 * and is only distinguishable from a Node instance by it's class or oid.
 * If a Node's parent is a NullNode instance, than they should be separated
 * in the data store (e.g. the foreign key should be null, if allowed by the database).
 * NullNode child instances should be ignored. The object id is created using 
 * the following code:
 * PersistenceFacade::composeOID(array('type' => $this->_type, 'id' => NULL))
 *
 * @author      ingo herwig <ingo@wemove.com>
 */
class NullNode extends Node
{
  /**
   * @see PersistentObject::getOID()
   */
  function getOID()
  {
    return PersistenceFacade::composeOID(array('type' => $this->_type, 'id' => NULL));
  }

  /**
   * @see PersistentObject::getDBID()
   */
  function getDBID()
  {
    return NULL;
  }
}
?>