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Public API for the Apache MyFaces Trinidad project
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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.myfaces.trinidad.change;

import org.w3c.dom.Document;
import org.w3c.dom.DocumentFragment;
import org.w3c.dom.Node;
import org.apache.myfaces.trinidad.logging.TrinidadLogger;

/**
 * Base class for specialized DocumentChanges that when applied will add a component
 * instance to the component tree.
 */
abstract public class AddComponentDocumentChange implements DocumentChange
{
  protected AddComponentDocumentChange(
    DocumentFragment fragment)
  {
    if (fragment == null)
      throw new IllegalArgumentException(_LOG.getMessage(
        "DOCUMENTFRAGMENT_REQUIRED"));
      
    _fragment = fragment;
  }
  
  
  /** 
   * Returns true if adding the DocumentChange should force the JSP Document
   * to reload
   */
  public boolean getForcesDocumentReload()
  {
    // adding components should force the document to reload
    return true;
  }

  /**
   * Returns the component that is to be added either as a child or a facet 
   *  while applying this Change. Returns null if the component cannot be 
   *  successfully re-constructed.
   */
  protected final DocumentFragment getComponentFragment()
  {
    return _fragment;
  }
  
  /**
   * Given the target Node, return the DocumentFragment, imported into the
   * target Document
   * @param targetNode 
   */
  protected final DocumentFragment getImportedComponentFragment(Node targetNode)
  {
    Document targetDocument = targetNode.getOwnerDocument();
    
    // return a deep import
    return (DocumentFragment)targetDocument.importNode(_fragment, true);
  }
  
  private final DocumentFragment _fragment;
  private static final TrinidadLogger _LOG = TrinidadLogger.createTrinidadLogger(
    AddComponentDocumentChange.class);
}