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Java > Open Source Codes > org > apache > commons > jxpath > ri > NamespaceResolver


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;
17
18
19 import java.util.HashMap JavaDoc;
20 import java.util.Iterator JavaDoc;
21 import java.util.Map JavaDoc;
22
23 import org.apache.commons.jxpath.Pointer;
24 import org.apache.commons.jxpath.ri.model.NodeIterator;
25 import org.apache.commons.jxpath.ri.model.NodePointer;
26
27 /**
28  * The reference implementation of JXPathContext.
29  *
30  * @author Dmitri Plotnikov
31  * @version $Revision: 1.2 $ $Date: 2004/06/29 22:57:20 $
32  */
33 public class NamespaceResolver implements Cloneable JavaDoc {
34     
35     protected HashMap JavaDoc namespaceMap = new HashMap JavaDoc();
36     protected HashMap JavaDoc reverseMap;
37     protected NodePointer pointer;
38     private boolean sealed;
39     
40     /**
41      * Registers a namespace prefix.
42      *
43      * @param prefix A namespace prefix
44      * @param namespaceURI A URI for that prefix
45      */
46     public void registerNamespace(String JavaDoc prefix, String JavaDoc namespaceURI) {
47         namespaceMap.put(prefix, namespaceURI);
48         reverseMap = null;
49     }
50     
51     /**
52      * Register a namespace for the expression context.
53      */
54     public void setNamespaceContextPointer(NodePointer pointer) {
55         this.pointer = pointer;
56     }
57     
58     public Pointer getNamespaceContextPointer() {
59         return pointer;
60     }
61     
62     /**
63      * Given a prefix, returns a registered namespace URI. If the requested
64      * prefix was not defined explicitly using the registerNamespace method,
65      * JXPathContext will then check the context node to see if the prefix is
66      * defined there. See
67      * {@link #setNamespaceContextPointer(Pointer) setNamespaceContextPointer}.
68      *
69      * @param prefix The namespace prefix to look up
70      * @return namespace URI or null if the prefix is undefined.
71      */
72     public String JavaDoc getNamespaceURI(String JavaDoc prefix) {
73         String JavaDoc uri = (String JavaDoc) namespaceMap.get(prefix);
74         if (uri == null && pointer != null) {
75             uri = pointer.getNamespaceURI(prefix);
76         }
77 // System.err.println("For prefix " + prefix + " URI=" + uri);
78 return uri;
79     }
80     
81     public String JavaDoc getPrefix(String JavaDoc namespaceURI) {
82         if (reverseMap == null) {
83             reverseMap = new HashMap JavaDoc();
84             NodeIterator ni = pointer.namespaceIterator();
85             if (ni != null) {
86                 for (int position = 1; ni.setPosition(position); position++) {
87                     NodePointer nsPointer = ni.getNodePointer();
88                     QName qname = nsPointer.getName();
89                     reverseMap.put(qname.getPrefix(), qname.getName());
90                 }
91             }
92             Iterator JavaDoc it = namespaceMap.entrySet().iterator();
93             while (it.hasNext()) {
94                 Map.Entry JavaDoc entry = (Map.Entry JavaDoc) it.next();
95                 reverseMap.put(entry.getValue(), entry.getKey());
96             }
97         }
98         String JavaDoc prefix = (String JavaDoc) reverseMap.get(namespaceURI);
99         return prefix;
100     }
101     
102     public boolean isSealed() {
103         return sealed;
104     }
105     
106     public void seal() {
107         sealed = true;
108     }
109     
110     public Object JavaDoc clone() {
111         try {
112             return super.clone();
113         }
114         catch (CloneNotSupportedException JavaDoc e) {
115             // Of course, it's supported.
116 e.printStackTrace();
117             return null;
118         }
119     }
120 }
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