/*
    * Copyright (C) 2007-2012 Argeo GmbH
    *
    * Licensed 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.argeo.eclipse.ui.jcr.util;
  
  import javax.jcr.Node;
  import javax.jcr.RepositoryException;
  
  import org.argeo.eclipse.ui.EclipseUiException;
  import org.eclipse.jface.viewers.IElementComparer;
  
  /** Compare JCR nodes based on their JCR identifiers, for use in JFace viewers. */
  public class NodeViewerComparer implements IElementComparer {
  
  	// force comparison on Node IDs only.
  	public boolean equals(Object elementA, Object elementB) {
  		if (!(elementA instanceof Node) || !(elementB instanceof Node)) {
  			return elementA == null ? elementB == null : elementA
  					.equals(elementB);
  		} else {
  
  			boolean result = false;
  			try {
  				String idA = ((Node) elementA).getIdentifier();
  				String idB = ((Node) elementB).getIdentifier();
  				result = idA == null ? idB == null : idA.equals(idB);
  			} catch (RepositoryException re) {
  				throw new EclipseUiException("cannot compare nodes", re);
  			}
  
  			return result;
  		}
  	}
  
  	public int hashCode(Object element) {
  		// TODO enhanced this method.
  		return element.getClass().toString().hashCode();
  	}
  }