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Java > Open Source Codes > com > caucho > xpath > pattern > CurrentPattern


1 /*
2  * Copyright (c) 1998-2006 Caucho Technology -- all rights reserved
3  *
4  * This file is part of Resin(R) Open Source
5  *
6  * Each copy or derived work must preserve the copyright notice and this
7  * notice unmodified.
8  *
9  * Resin Open Source is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * Resin Open Source is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
17  * of NON-INFRINGEMENT. See the GNU General Public License for more
18  * details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with Resin Open Source; if not, write to the
22  * Free SoftwareFoundation, Inc.
23  * 59 Temple Place, Suite 330
24  * Boston, MA 02111-1307 USA
25  *
26  * @author Scott Ferguson
27  */
28
29 package com.caucho.xpath.pattern;
30
31 import com.caucho.xpath.Env;
32 import com.caucho.xpath.ExprEnvironment;
33 import com.caucho.xpath.XPathException;
34
35 import org.w3c.dom.Node JavaDoc;
36
37 /**
38  * Matches the current node.
39  */
40 public class CurrentPattern extends Axis {
41   public CurrentPattern()
42   {
43     super(null);
44   }
45
46   /**
47    * Matches the current node
48    *
49    * @param node the starting node
50    * @param env the xpath environment
51    *
52    * @return true if the node is the current node.
53    */
54   public boolean match(Node JavaDoc node, ExprEnvironment env)
55   {
56     return (node == env.getCurrentNode());
57   }
58   
59   /**
60    * Returns true if the pattern selects a single node
61    */
62   boolean isSingleSelect()
63   {
64     return true;
65   }
66
67   /**
68    * Creates a new node iterator.
69    *
70    * @param node the starting node
71    * @param env the xpath environment
72    * @param match the axis match pattern
73    *
74    * @return the node iterator
75    */
76   public NodeIterator createNodeIterator(Node JavaDoc node, ExprEnvironment env,
77                                          AbstractPattern match)
78     throws XPathException
79   {
80     Node JavaDoc current = env.getCurrentNode();
81     
82     if (match == null || match.match(current, env))
83       return new SingleNodeIterator(env, current);
84     else
85       return null;
86   }
87
88   /**
89    * Returns the first node in the selection order.
90    *
91    * @param node the current node
92    *
93    * @return the first node
94    */
95   public Node JavaDoc firstNode(Node JavaDoc node, ExprEnvironment env)
96   {
97     return env.getCurrentNode();
98   }
99
100   /**
101    * Returns the next node in the selection order.
102    *
103    * @param node the current node
104    * @param last the last node
105    *
106    * @return the next node
107    */
108   public Node JavaDoc nextNode(Node JavaDoc node, Node JavaDoc last)
109   {
110     return null;
111   }
112   
113   /**
114    * There is only a single node in the current
115    */
116   public int position(Node JavaDoc node, Env env, AbstractPattern pattern)
117   {
118     return 1;
119   }
120   /**
121    * There is only a single node in the current
122    */
123   public int count(Node JavaDoc node, Env env, Node JavaDoc context)
124   {
125     return 1;
126   }
127
128   public String JavaDoc toString()
129   {
130     return "current()";
131   }
132 }
133
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