1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one
3  * or more contributor license agreements. See the NOTICE file
4  * distributed with this work for additional information
5  * regarding copyright ownership. The ASF licenses this file
6  * to you under the Apache License, Version 2.0 (the  "License");
7  * you may not use this file except in compliance with the License.
8  * You may obtain a copy of the License at
9  *
10  *     http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18 /*
19  * $Id: PrefixResolverDefault.java 468655 2006-10-28 07:12:06Z minchau $
20  */
21 package org.apache.xml.utils;
22 
23 import org.w3c.dom.NamedNodeMap;
24 import org.w3c.dom.Node;
25 
26 /**
27  * This class implements a generic PrefixResolver that
28  * can be used to perform prefix-to-namespace lookup
29  * for the XPath object.
30  * @xsl.usage general
31  */
32 public class PrefixResolverDefault implements PrefixResolver
33 {
34 
35   /**
36    * The context to resolve the prefix from, if the context
37    * is not given.
38    */
39   Node m_context;
40 
41   /**
42    * Construct a PrefixResolverDefault object.
43    * @param xpathExpressionContext The context from
44    * which XPath expression prefixes will be resolved.
45    * Warning: This will not work correctly if xpathExpressionContext
46    * is an attribute node.
47    */
PrefixResolverDefault(Node xpathExpressionContext)48   public PrefixResolverDefault(Node xpathExpressionContext)
49   {
50     m_context = xpathExpressionContext;
51   }
52 
53   /**
54    * Given a namespace, get the corrisponding prefix.  This assumes that
55    * the PrevixResolver hold's it's own namespace context, or is a namespace
56    * context itself.
57    * @param prefix Prefix to resolve.
58    * @return Namespace that prefix resolves to, or null if prefix
59    * is not bound.
60    */
getNamespaceForPrefix(String prefix)61   public String getNamespaceForPrefix(String prefix)
62   {
63     return getNamespaceForPrefix(prefix, m_context);
64   }
65 
66   /**
67    * Given a namespace, get the corrisponding prefix.
68    * Warning: This will not work correctly if namespaceContext
69    * is an attribute node.
70    * @param prefix Prefix to resolve.
71    * @param namespaceContext Node from which to start searching for a
72    * xmlns attribute that binds a prefix to a namespace.
73    * @return Namespace that prefix resolves to, or null if prefix
74    * is not bound.
75    */
getNamespaceForPrefix(String prefix, org.w3c.dom.Node namespaceContext)76   public String getNamespaceForPrefix(String prefix,
77                                       org.w3c.dom.Node namespaceContext)
78   {
79 
80     Node parent = namespaceContext;
81     String namespace = null;
82 
83     if (prefix.equals("xml"))
84     {
85       namespace = Constants.S_XMLNAMESPACEURI;
86     }
87     else
88     {
89       int type;
90 
91       while ((null != parent) && (null == namespace)
92              && (((type = parent.getNodeType()) == Node.ELEMENT_NODE)
93                  || (type == Node.ENTITY_REFERENCE_NODE)))
94       {
95         if (type == Node.ELEMENT_NODE)
96         {
97                 if (parent.getNodeName().indexOf(prefix+":") == 0)
98                         return parent.getNamespaceURI();
99           NamedNodeMap nnm = parent.getAttributes();
100 
101           for (int i = 0; i < nnm.getLength(); i++)
102           {
103             Node attr = nnm.item(i);
104             String aname = attr.getNodeName();
105             boolean isPrefix = aname.startsWith("xmlns:");
106 
107             if (isPrefix || aname.equals("xmlns"))
108             {
109               int index = aname.indexOf(':');
110               String p = isPrefix ? aname.substring(index + 1) : "";
111 
112               if (p.equals(prefix))
113               {
114                 namespace = attr.getNodeValue();
115 
116                 break;
117               }
118             }
119           }
120         }
121 
122         parent = parent.getParentNode();
123       }
124     }
125 
126     return namespace;
127   }
128 
129   /**
130    * Return the base identifier.
131    *
132    * @return null
133    */
getBaseIdentifier()134   public String getBaseIdentifier()
135   {
136     return null;
137   }
138 	/**
139 	 * @see PrefixResolver#handlesNullPrefixes()
140 	 */
handlesNullPrefixes()141 	public boolean handlesNullPrefixes() {
142 		return false;
143 	}
144 
145 }
146