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Java > Open Source Codes > org > apache > commons > jxpath > ri > axes > SelfContext


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 }
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