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


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.ExprEnvironment;
32
33 import org.w3c.dom.Document JavaDoc;
34 import org.w3c.dom.Node JavaDoc;
35
36 /**
37  * Represents a match with the document root.
38  */
39 public class FromRoot extends Axis {
40   public FromRoot()
41   {
42     super(null);
43   }
44
45   /**
46    * Matches the owner document.
47    *
48    * @param node the current node
49    * @param env the variable environment
50    *
51    * @return true if the node is the owner document.
52    */
53   public boolean match(Node JavaDoc node, ExprEnvironment env)
54   {
55     return (node instanceof Document JavaDoc);
56   }
57
58   /**
59    * Returns the first node in the selection order.
60    *
61    * @param node the current node
62    *
63    * @return the first node
64    */
65   public Node JavaDoc firstNode(Node JavaDoc node, ExprEnvironment env)
66   {
67     Node JavaDoc doc = node.getOwnerDocument();
68
69     if (doc != null)
70       return doc;
71     else
72       return node;
73   }
74
75   /**
76    * Returns the next node in the selection order.
77    *
78    * @param node the current node
79    * @param lastNode the last node
80    *
81    * @return the next node
82    */
83   public Node JavaDoc nextNode(Node JavaDoc node, Node JavaDoc lastNode)
84   {
85     return null;
86   }
87
88   /**
89    * The root is strictly ascending.
90    */
91   public boolean isStrictlyAscending()
92   {
93     return true;
94   }
95   
96   /**
97    * Returns true if the pattern selects a single node
98    */
99   boolean isSingleSelect()
100   {
101     return true;
102   }
103
104   /**
105    * Returns true if the two patterns are equal.
106    */
107   public boolean equals(Object JavaDoc b)
108   {
109     return b instanceof FromRoot;
110   }
111
112   public String JavaDoc toString()
113   {
114     return "/";
115   }
116 }
117
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