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1   /*
2    * Copyright 1999-2004 The Apache Software Foundation
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.apache.commons.jxpath.ri.axes;
17  
18  import org.apache.commons.jxpath.ri.EvalContext;
19  import org.apache.commons.jxpath.ri.QName;
20  import org.apache.commons.jxpath.ri.compiler.NodeNameTest;
21  import org.apache.commons.jxpath.ri.compiler.NodeTest;
22  import org.apache.commons.jxpath.ri.model.NodeIterator;
23  import org.apache.commons.jxpath.ri.model.NodePointer;
24  
25  /***
26   * EvalContext that walks the "attribute::" axis.
27   *
28   * @author Dmitri Plotnikov
29   * @version $Revision: 1.10 $ $Date: 2004/02/29 14:17:38 $
30   */
31  public class AttributeContext extends EvalContext {
32      private NodeTest nodeTest;
33      private boolean setStarted = false;
34      private NodeIterator iterator;
35      private NodePointer currentNodePointer;
36  
37      /***
38       * @param parentContext represents the previous step on the path
39       * @param nameTest is the name of the attribute we are looking for
40       */
41      public AttributeContext(EvalContext parentContext, NodeTest nodeTest) {
42          super(parentContext);
43          this.nodeTest = nodeTest;
44      }
45  
46      public NodePointer getCurrentNodePointer() {
47          return currentNodePointer;
48      }
49  
50      public void reset() {
51          setStarted = false;
52          iterator = null;
53          super.reset();
54      }
55  
56      public boolean setPosition(int position) {
57          if (position < getCurrentPosition()) {
58              reset();
59          }
60  
61          while (getCurrentPosition() < position) {
62              if (!nextNode()) {
63                  return false;
64              }
65          }
66          return true;
67      }
68  
69      public boolean nextNode() {
70          super.setPosition(getCurrentPosition() + 1);
71          if (!setStarted) {
72              setStarted = true;
73              if (!(nodeTest instanceof NodeNameTest)) {
74                  return false;
75              }
76              QName name = ((NodeNameTest) nodeTest).getNodeName();
77              iterator =
78                  parentContext.getCurrentNodePointer().attributeIterator(name);
79          }
80  
81          if (iterator == null) {
82              return false;
83          }
84          if (!iterator.setPosition(iterator.getPosition() + 1)) {
85              return false;
86          }
87          currentNodePointer = iterator.getNodePointer();
88          return true;
89      }
90  }