utils/NodeViewerComparer.java

   1 /*
   2  * Copyright (C) 2007-2012 Argeo GmbH
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *         http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 package org.argeo.eclipse.ui.jcr.utils;
  17
  18 import javax.jcr.Node;
  19 import javax.jcr.RepositoryException;
  20
  21 import org.argeo.eclipse.ui.EclipseUiException;
  22 import org.eclipse.jface.viewers.IElementComparer;
  23
  24 /** Compare JCR nodes based on their JCR identifiers, for use in JFace viewers. */
  25 public class NodeViewerComparer implements IElementComparer {
  26
  27         // force comparison on Node IDs only.
  28         public boolean equals(Object elementA, Object elementB) {
  29                 if (!(elementA instanceof Node) || !(elementB instanceof Node)) {
  30                         return elementA == null ? elementB == null : elementA
  31                                         .equals(elementB);
  32                 } else {
  33
  34                         boolean result = false;
  35                         try {
  36                                 String idA = ((Node) elementA).getIdentifier();
  37                                 String idB = ((Node) elementB).getIdentifier();
  38                                 result = idA == null ? idB == null : idA.equals(idB);
  39                         } catch (RepositoryException re) {
  40                                 throw new EclipseUiException("cannot compare nodes", re);
  41                         }
  42
  43                         return result;
  44                 }
  45         }
  46
  47         public int hashCode(Object element) {
  48                 // TODO enhanced this method.
  49                 return element.getClass().toString().hashCode();
  50         }
  51 }