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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.Pointer;
19  import org.apache.commons.jxpath.ri.EvalContext;
20  import org.apache.commons.jxpath.ri.compiler.NodeTest;
21  import org.apache.commons.jxpath.ri.model.NodePointer;
22  
23  /***
24   * EvalContext  that returns the current node from the parent context if the
25   * test succeeds.
26   *
27   * @author Dmitri Plotnikov
28   * @version $Revision: 1.12 $ $Date: 2004/02/29 14:17:37 $
29   */
30  public class SelfContext extends EvalContext {
31      private NodeTest nodeTest;
32      private boolean startedSet = false;
33      private NodePointer nodePointer;
34  
35      public SelfContext(EvalContext parentContext, NodeTest nodeTest) {
36          super(parentContext);
37          this.nodeTest = nodeTest;
38      }
39  
40      public Pointer getSingleNodePointer() {
41          return parentContext.getSingleNodePointer();
42      }
43  
44      public NodePointer getCurrentNodePointer() {
45          if (position == 0) {
46              if (!setPosition(1)) {
47                  return null;
48              }
49          }
50          return nodePointer;
51      }
52  
53      public boolean nextNode() {
54          return setPosition(getCurrentPosition() + 1);
55      }
56  
57      public void reset() {
58          super.reset();
59          startedSet = false;
60      }
61  
62      public boolean setPosition(int position) {
63          if (position != 1) {
64              return false;
65          }
66          super.setPosition(position);
67          if (!startedSet) {
68              startedSet = true;
69              nodePointer = (NodePointer) parentContext.getCurrentNodePointer();
70          }
71  
72          if (nodePointer == null) {
73              return false;
74          }
75  
76          return nodeTest == null || nodePointer.testNode(nodeTest);
77      }
78  }