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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.configuration.tree.xpath;
18  
19  import java.util.List;
20  import java.util.Locale;
21  
22  import org.apache.commons.configuration.tree.ConfigurationNode;
23  import org.apache.commons.jxpath.ri.Compiler;
24  import org.apache.commons.jxpath.ri.QName;
25  import org.apache.commons.jxpath.ri.compiler.NodeTest;
26  import org.apache.commons.jxpath.ri.compiler.NodeTypeTest;
27  import org.apache.commons.jxpath.ri.model.NodeIterator;
28  import org.apache.commons.jxpath.ri.model.NodePointer;
29  
30  /**
31   * <p>
32   * A specific {@code NodePointer} implementation for configuration nodes.
33   * </p>
34   * <p>
35   * This is needed for queries using JXPath.
36   * </p>
37   *
38   * @since 1.3
39   * @author <a
40   * href="http://commons.apache.org/configuration/team-list.html">Commons
41   * Configuration team</a>
42   * @version $Id: ConfigurationNodePointer.java 1206496 2011-11-26 17:01:14Z oheger $
43   */
44  class ConfigurationNodePointer extends NodePointer
45  {
46      /**
47       * The serial version UID.
48       */
49      private static final long serialVersionUID = -1087475639680007713L;
50  
51      /** Stores the associated configuration node. */
52      private ConfigurationNode node;
53  
54      /**
55       * Creates a new instance of {@code ConfigurationNodePointer}.
56       *
57       * @param node the node
58       * @param locale the locale
59       */
60      public ConfigurationNodePointer(ConfigurationNode node, Locale locale)
61      {
62          super(null, locale);
63          this.node = node;
64      }
65  
66      /**
67       * Creates a new instance of {@code ConfigurationNodePointer} and
68       * initializes it with its parent pointer.
69       *
70       * @param parent the parent pointer
71       * @param node the associated node
72       */
73      public ConfigurationNodePointer(NodePointer parent, ConfigurationNode node)
74      {
75          super(parent);
76          this.node = node;
77      }
78  
79      /**
80       * Returns a flag whether this node is a leaf. This is the case if there are
81       * no child nodes.
82       *
83       * @return a flag if this node is a leaf
84       */
85      @Override
86      public boolean isLeaf()
87      {
88          return node.getChildrenCount() < 1;
89      }
90  
91      /**
92       * Returns a flag if this node is a collection. This is not the case.
93       *
94       * @return the collection flag
95       */
96      @Override
97      public boolean isCollection()
98      {
99          return false;
100     }
101 
102     /**
103      * Returns this node's length. This is always 1.
104      *
105      * @return the node's length
106      */
107     @Override
108     public int getLength()
109     {
110         return 1;
111     }
112 
113     /**
114      * Checks whether this node pointer refers to an attribute node. This method
115      * checks the attribute flag of the associated configuration node.
116      *
117      * @return the attribute flag
118      */
119     @Override
120     public boolean isAttribute()
121     {
122         return node.isAttribute();
123     }
124 
125     /**
126      * Returns this node's name.
127      *
128      * @return the name
129      */
130     @Override
131     public QName getName()
132     {
133         return new QName(null, node.getName());
134     }
135 
136     /**
137      * Returns this node's base value. This is the associated configuration
138      * node.
139      *
140      * @return the base value
141      */
142     @Override
143     public Object getBaseValue()
144     {
145         return node;
146     }
147 
148     /**
149      * Returns the immediate node. This is the associated configuration node.
150      *
151      * @return the immediate node
152      */
153     @Override
154     public Object getImmediateNode()
155     {
156         return node;
157     }
158 
159     /**
160      * Returns the value of this node.
161      *
162      * @return the represented node's value
163      */
164     @Override
165     public Object getValue()
166     {
167         return node.getValue();
168     }
169 
170     /**
171      * Sets the value of this node.
172      *
173      * @param value the new value
174      */
175     @Override
176     public void setValue(Object value)
177     {
178         node.setValue(value);
179     }
180 
181     /**
182      * Compares two child node pointers.
183      *
184      * @param pointer1 one pointer
185      * @param pointer2 another pointer
186      * @return a flag, which pointer should be sorted first
187      */
188     @Override
189     public int compareChildNodePointers(NodePointer pointer1,
190             NodePointer pointer2)
191     {
192         ConfigurationNode node1 = (ConfigurationNode) pointer1.getBaseValue();
193         ConfigurationNode node2 = (ConfigurationNode) pointer2.getBaseValue();
194 
195         // attributes will be sorted before child nodes
196         if (node1.isAttribute() && !node2.isAttribute())
197         {
198             return -1;
199         }
200         else if (node2.isAttribute() && !node1.isAttribute())
201         {
202             return 1;
203         }
204 
205         else
206         {
207             // sort based on the occurrence in the sub node list
208             List<ConfigurationNode> subNodes = node1.isAttribute() ? node.getAttributes() : node
209                     .getChildren();
210             for (ConfigurationNode child : subNodes)
211             {
212                 if (child == node1)
213                 {
214                     return -1;
215                 }
216                 else if (child == node2)
217                 {
218                     return 1;
219                 }
220             }
221             return 0; // should not happen
222         }
223     }
224 
225     /**
226      * Returns an iterator for the attributes that match the given name.
227      *
228      * @param name the attribute name
229      * @return the iterator for the attributes
230      */
231     @Override
232     public NodeIterator attributeIterator(QName name)
233     {
234         return new ConfigurationNodeIteratorAttribute(this, name);
235     }
236 
237     /**
238      * Returns an iterator for the children of this pointer that match the given
239      * test object.
240      *
241      * @param test the test object
242      * @param reverse the reverse flag
243      * @param startWith the start value of the iteration
244      */
245     @Override
246     public NodeIterator childIterator(NodeTest test, boolean reverse,
247             NodePointer startWith)
248     {
249         return new ConfigurationNodeIteratorChildren(this, test, reverse,
250                 startWith);
251     }
252 
253     /**
254      * Tests if this node matches the given test. Configuration nodes are text
255      * nodes, too because they can contain a value.
256      *
257      * @param test the test object
258      * @return a flag if this node corresponds to the test
259      */
260     @Override
261     public boolean testNode(NodeTest test)
262     {
263         if (test instanceof NodeTypeTest
264                 && ((NodeTypeTest) test).getNodeType() == Compiler.NODE_TYPE_TEXT)
265         {
266             return true;
267         }
268         return super.testNode(test);
269     }
270 }