Namespaces


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.cocoon.components.serializers.util;
17  
18  import org.xml.sax.SAXException  ;
19  
20  /**
21   * The <code>Namespaces</code> class is an utility class implementing a
22   * stack for XML namespaces declarations.
23   * 
24   * @author <a HREF="mailto:pier@apache.org">Pier Fumagalli</a>, February 2003
25   * @version CVS $Id: Namespaces.java 54845 2004-10-15 10:52:09Z cziegeler $
26   */
27  public class Namespaces {
28      /** The array of all URIs in this stack. */
29      private String   uri[] = new String  [512];
30      /** The array of all prefixes in this stack. */
31      private String   pre[] = new String  [512];
32      /** The number of URI/prefix mappings in this stack. */
33      private int depth = 0;
34      /** The last "committed" namespace. */
35      private int last = 0;
36  
37      /** The index of the namespace prefix in for <code>commit()</code>. */
38      public static final int NAMESPACE_PREFIX = 0;
39      /** The index of the namespace uri in for <code>commit()</code>. */
40      public static final int NAMESPACE_URI = 1;
41  
42      /**
43       * Create a new <code>Namespaces</code> instance.
44       */
45      public Namespaces() {
46          super();
47  
48          this.push("", "");
49          this.push("xml", "http://www.w3.org/XML/1998/namespace");
50          this.last = this.depth;
51      }
52  
53      /**
54       * Push a new namespace declaration into this stack.
55       *
56       * @param prefix The prefix to associate with the specified URI.
57       * @param uri The URI associated with the namespace.
58       */
59      public synchronized void push(String   prefix, String   uri) {
60          if (this.depth == this.uri.length) {
61              int newDepth = this.uri.length + (this.uri.length >> 1);
62              String   newUri[] = new String  [newDepth];
63              String   newPre[] = new String  [newDepth];
64              System.arraycopy(this.uri, 0, newUri, 0, this.depth);
65              System.arraycopy(this.pre, 0, newPre, 0, this.depth);
66              this.uri = newUri;
67              this.pre = newPre;
68          }
69  
70          this.uri[this.depth] = uri;
71          this.pre[this.depth] = prefix;
72          this.depth ++;
73      }
74  
75      /**
76       * Pop a new namespace declaration out of this stack.
77       * <br />
78       * If more than one namespace is associated with the specified namespace,
79       * only the last pushed namespace will be popped out.
80       *
81       * @param prefix The prefix to associate with the specified URI.
82       * @throws SAXException If the prefix was not mapped in this stack.
83       */
84      public synchronized void pop(String   prefix)
85      throws SAXException   {
86          for (int x = this.position(prefix, pre); x < this.depth; x++) {
87              int k = (x + 1);
88              this.pre[x] = this.pre[k];
89              this.uri[x] = this.uri[k];
90          }
91          //this.pre[this.depth] = null;
92          //this.uri[this.depth] = null;
93          this.last--;
94          this.depth--;
95      }
96  
97      /**
98       * Qualify an XML name.
99       * <br />
100      * Given a URI, local name and qualified name as passed to the SAX
101      * <code>ContentHandler</code> interface in the <code>startElement()</code>
102      * method, this method will always return a valid XML name token usable
103      * for serialization (checking namespaces URIs and prefixes).
104      *
105      * @param nsuri The Namespace URI, or the empty string if the element has
106      *              no namespace URI or if namespace processing is not being
107      *              performed.
108      * @param local The local name (without prefix), or the empty string if
109      *              namespace processing is not being performed.
110      * @param qualified The qualified name (with prefix), or the empty string
111      *                  if qualified names are not available.
112      * @throws SAXException If the specified URI is not mapped with a prefix.
113      */
114     public String   qualify(String   nsuri, String   local, String   qualified)
115     throws SAXException   {
116         if (nsuri == null) nsuri = "";
117         if (local == null) local = "";
118         if (qualified == null) qualified = "";
119 
120         /** No namespaces processing. */
121         if ((nsuri.length() == 0 ) && (local.length() == 0)) return(qualified);
122 
123         /*
124          * Get the prefix for the given namespace and return the qualified
125          * name: "prefix:local" if prefix is not empty, "local" otherwise.
126          */
127         int position = position(nsuri, this.uri);
128         if (this.pre[position].length() > 0) {
129             return(this.pre[position] + ':' + local);
130         }
131         return(local);
132     }
133 
134     /**
135      * Checkpoint this stack, returning the list of all namespaces added since
136      * the last <code>commit()</code> or <code>pop(...)</code> call.
137      */
138     public String  [][] commit() {
139         int size = this.depth - this.last;
140         String   result[][] = new String  [size][2];
141         int k = 0;
142         for (int x = this.last; x < this.depth; x++) {
143             result[k][NAMESPACE_PREFIX] = this.pre[x];
144             result[k][NAMESPACE_URI]    = this.uri[x];
145             k++;
146         }
147         this.last = this.depth;
148         return(result);
149     }
150 
151     /**
152      * Return the namespace URI associated with the specified prefix.
153      *
154      * @throws SAXException If the prefix cannot be mapped.
155      */
156     public String   getUri(String   prefix)
157     throws SAXException   {
158         return(this.uri[this.position(prefix, this.pre)]);
159     }
160 
161     /**
162      * Return the namespace prefix associated with the specified URI.
163      *
164      * @throws SAXException If the URI cannot be mapped.
165      */
166     public String   getPrefix(String   nsuri)
167     throws SAXException   {
168         return(this.pre[this.position(nsuri, this.uri)]);
169     }
170 
171     /**
172      * Return the position of the given check <code>String</code> in the
173      * specified <code>String</code> array.
174      */
175     private int position(String   check, String   array[])
176     throws SAXException   {
177         int x = this.depth;
178         while (true) {
179             if (check.equals(array[--x])) return(x);
180             if (x == 0) break;
181         }
182         throw new SAXException  ("Unable to map \"" + check + "\"");
183     }
184 
185 }
186
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