server/plugins/org.argeo.jcr.ui.explorer/src/main/java/org/argeo/jcr/ui/explorer/model/SingleJcrNode.java

   1 /*
   2  * Copyright (C) 2007-2012 Mathieu Baudier
   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.jcr.ui.explorer.model;
  17
  18 import javax.jcr.Node;
  19 import javax.jcr.NodeIterator;
  20 import javax.jcr.RepositoryException;
  21 import javax.jcr.Workspace;
  22
  23 import org.argeo.ArgeoException;
  24 import org.argeo.eclipse.ui.TreeParent;
  25
  26 /**
  27  * UI Tree component. Wraps a node of a JCR {@link Workspace}. It also keeps a
  28  * reference to its parent node that can either be a {@link WorkspaceNode}, a
  29  * {@link SingleJcrNode} or null if the node is "mounted" as the root of the UI
  30  * tree.
  31  */
  32
  33 public class SingleJcrNode extends TreeParent implements UiNode {
  34
  35         private final Node node;
  36         private String alias = null;
  37
  38         // keeps a local reference to the node's name to avoid exception when the
  39         // session is lost
  40         // private final String name;
  41
  42         /** Creates a new UiNode in the UI Tree */
  43         public SingleJcrNode(TreeParent parent, Node node, String name) {
  44                 super(name);
  45                 setParent(parent);
  46                 this.node = node;
  47         }
  48
  49         /**
  50          * Creates a new UiNode in the UI Tree, keeping a reference to the alias of
  51          * the corresponding repository in the current UI environment. It is useful
  52          * to be able to mount nodes as roots of the UI tree.
  53          */
  54         public SingleJcrNode(TreeParent parent, Node node, String name, String alias) {
  55                 super(name);
  56                 setParent(parent);
  57                 this.node = node;
  58                 this.alias = alias;
  59         }
  60
  61         /** returns the node wrapped by the current Ui object */
  62         public Node getNode() {
  63                 return node;
  64         }
  65
  66         /**
  67          * Returns the alias corresponding to the repository abstraction that
  68          * contains current node. If the current object is mounted as root of the UI
  69          * tree, the alias is stored in the object. Otherwise, we must browse the
  70          * tree backward to the RepositoryNode.
  71          *
  72          * Alias is then cached in the current object so that next time it will be
  73          * here.
  74          */
  75         public String getAlias() {
  76                 if (alias == null) {
  77                         alias = ((UiNode) getParent()).getAlias();
  78                 }
  79                 return alias;
  80         }
  81
  82         /**
  83          * Override normal behaviour to initialize children only when first
  84          * requested
  85          */
  86         @Override
  87         public synchronized Object[] getChildren() {
  88                 if (isLoaded()) {
  89                         return super.getChildren();
  90                 } else {
  91                         // initialize current object
  92                         try {
  93                                 NodeIterator ni = node.getNodes();
  94                                 while (ni.hasNext()) {
  95                                         Node curNode = ni.nextNode();
  96                                         addChild(new SingleJcrNode(this, curNode, curNode.getName()));
  97                                 }
  98                                 return super.getChildren();
  99                         } catch (RepositoryException re) {
 100                                 throw new ArgeoException(
 101                                                 "Unexcpected error while initializing children SingleJcrNode",
 102                                                 re);
 103                         }
 104                 }
 105         }
 106
 107         @Override
 108         public boolean hasChildren() {
 109                 try {
 110                         return node.hasNodes();
 111                 } catch (RepositoryException re) {
 112                         throw new ArgeoException(
 113                                         "Unexpected error while checking children node existence",
 114                                         re);
 115                 }
 116         }
 117
 118 }