DTMNamedNodeMap


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  /*
17   * $Id: DTMNamedNodeMap.java,v 1.8 2004/02/16 23:06:11 minchau Exp $
18   */
19  package org.apache.xml.dtm.ref;
20  
21  import org.apache.xml.dtm.DTM;
22  
23  import org.w3c.dom.DOMException  ;
24  import org.w3c.dom.NamedNodeMap  ;
25  import org.w3c.dom.Node  ;
26  
27  /**
28   * DTMNamedNodeMap is a quickie (as opposed to quick) implementation of the DOM's
29   * NamedNodeMap interface, intended to support DTMProxy's getAttributes()
30   * call.
31   * <p>
32   * ***** Note: this does _not_ current attempt to cache any of the data;
33   * if you ask for attribute 27 and then 28, you'll have to rescan the first
34   * 27. It should probably at least keep track of the last one retrieved,
35   * and possibly buffer the whole array.
36   * <p>
37   * ***** Also note that there's no fastpath for the by-name query; we search
38   * linearly until we find it or fail to find it. Again, that could be
39   * optimized at some cost in object creation/storage.
40   * @xsl.usage internal
41   */
42  public class DTMNamedNodeMap implements NamedNodeMap  
43  {
44  
45    /** The DTM for this node. */
46    DTM dtm;
47  
48    /** The DTM element handle. */
49    int element;
50  
51    /** The number of nodes in this map. */
52    short m_count = -1;
53  
54    /**
55     * Create a getAttributes NamedNodeMap for a given DTM element node
56     *
57     * @param dtm The DTM Reference, must be non-null.
58     * @param element The DTM element handle.
59     */
60    public DTMNamedNodeMap(DTM dtm, int element)
61    {
62      this.dtm = dtm;
63      this.element = element;
64    }
65  
66    /**
67     * Return the number of Attributes on this Element
68     *
69     * @return The number of nodes in this map.
70     */
71    public int getLength()
72    {
73  
74      if (m_count == -1)
75      {
76        short count = 0;
77  
78        for (int n = dtm.getFirstAttribute(element); n != -1;
79                n = dtm.getNextAttribute(n))
80        {
81          ++count;
82        }
83  
84        m_count = count;
85      }
86  
87      return (int) m_count;
88    }
89  
90    /**
91     * Retrieves a node specified by name.
92     * @param nameThe <code>nodeName</code> of a node to retrieve.
93     *
94     * @param name Name of the item being requested.
95     * @return A <code>Node</code> (of any type) with the specified
96     *   <code>nodeName</code>, or <code>null</code> if it does not identify
97     *   any node in this map.
98     */
99    public Node   getNamedItem(String   name)
100   {
101 
102     for (int n = dtm.getFirstAttribute(element); n != -1;
103             n = dtm.getNextAttribute(n))
104     {
105       if (dtm.getNodeName(n).equals(name))
106         return dtm.getNode(n);
107     }
108 
109     return null;
110   }
111 
112   /**
113    * Returns the <code>index</code>th item in the map. If <code>index</code>
114    * is greater than or equal to the number of nodes in this map, this
115    * returns <code>null</code>.
116    * @param indexIndex into this map.
117    *
118    * @param i The index of the requested item.
119    * @return The node at the <code>index</code>th position in the map, or
120    *   <code>null</code> if that is not a valid index.
121    */
122   public Node   item(int i)
123   {
124 
125     int count = 0;
126 
127     for (int n = dtm.getFirstAttribute(element); n != -1;
128             n = dtm.getNextAttribute(n))
129     {
130       if (count == i)
131         return dtm.getNode(n);
132       else
133         ++count;
134     }
135 
136     return null;
137   }
138 
139   /**
140    * Adds a node using its <code>nodeName</code> attribute. If a node with
141    * that name is already present in this map, it is replaced by the new
142    * one.
143    * <br>As the <code>nodeName</code> attribute is used to derive the name
144    * which the node must be stored under, multiple nodes of certain types
145    * (those that have a "special" string value) cannot be stored as the
146    * names would clash. This is seen as preferable to allowing nodes to be
147    * aliased.
148    * @param newNode node to store in this map. The node will later be
149    *   accessible using the value of its <code>nodeName</code> attribute.
150    *
151    * @return If the new <code>Node</code> replaces an existing node the
152    *   replaced <code>Node</code> is returned, otherwise <code>null</code>
153    *   is returned.
154    * @exception DOMException
155    *   WRONG_DOCUMENT_ERR: Raised if <code>arg</code> was created from a
156    *   different document than the one that created this map.
157    *   <br>NO_MODIFICATION_ALLOWED_ERR: Raised if this map is readonly.
158    *   <br>INUSE_ATTRIBUTE_ERR: Raised if <code>arg</code> is an
159    *   <code>Attr</code> that is already an attribute of another
160    *   <code>Element</code> object. The DOM user must explicitly clone
161    *   <code>Attr</code> nodes to re-use them in other elements.
162    */
163   public Node   setNamedItem(Node   newNode)
164   {
165     throw new DTMException(DTMException.NO_MODIFICATION_ALLOWED_ERR);
166   }
167 
168   /**
169    * Removes a node specified by name. When this map contains the attributes
170    * attached to an element, if the removed attribute is known to have a
171    * default value, an attribute immediately appears containing the
172    * default value as well as the corresponding namespace URI, local name,
173    * and prefix when applicable.
174    * @param name The <code>nodeName</code> of the node to remove.
175    *
176    * @return The node removed from this map if a node with such a name
177    *   exists.
178    * @exception DOMException
179    *   NOT_FOUND_ERR: Raised if there is no node named <code>name</code> in
180    *   this map.
181    *   <br>NO_MODIFICATION_ALLOWED_ERR: Raised if this map is readonly.
182    */
183   public Node   removeNamedItem(String   name)
184   {
185     throw new DTMException(DTMException.NO_MODIFICATION_ALLOWED_ERR);
186   }
187 
188   /**
189    * Retrieves a node specified by local name and namespace URI. HTML-only
190    * DOM implementations do not need to implement this method.
191    * @param namespaceURI The namespace URI of the node to retrieve.
192    * @param localName The local name of the node to retrieve.
193    *
194    * @return A <code>Node</code> (of any type) with the specified local
195    *   name and namespace URI, or <code>null</code> if they do not
196    *   identify any node in this map.
197    * @since DOM Level 2
198    */
199   public Node   getNamedItemNS(String   namespaceURI, String   localName)
200   {
201     throw new DTMException(DTMException.NOT_SUPPORTED_ERR);
202   }
203 
204   /**
205    * Adds a node using its <code>namespaceURI</code> and
206    * <code>localName</code>. If a node with that namespace URI and that
207    * local name is already present in this map, it is replaced by the new
208    * one.
209    * <br>HTML-only DOM implementations do not need to implement this method.
210    * @param arg A node to store in this map. The node will later be
211    *   accessible using the value of its <code>namespaceURI</code> and
212    *   <code>localName</code> attributes.
213    *
214    * @return If the new <code>Node</code> replaces an existing node the
215    *   replaced <code>Node</code> is returned, otherwise <code>null</code>
216    *   is returned.
217    * @exception DOMException
218    *   WRONG_DOCUMENT_ERR: Raised if <code>arg</code> was created from a
219    *   different document than the one that created this map.
220    *   <br>NO_MODIFICATION_ALLOWED_ERR: Raised if this map is readonly.
221    *   <br>INUSE_ATTRIBUTE_ERR: Raised if <code>arg</code> is an
222    *   <code>Attr</code> that is already an attribute of another
223    *   <code>Element</code> object. The DOM user must explicitly clone
224    *   <code>Attr</code> nodes to re-use them in other elements.
225    * @since DOM Level 2
226    */
227   public Node   setNamedItemNS(Node   arg) throws DOMException  
228   {
229     throw new DTMException(DTMException.NO_MODIFICATION_ALLOWED_ERR);
230   }
231 
232   /**
233    * Removes a node specified by local name and namespace URI. A removed
234    * attribute may be known to have a default value when this map contains
235    * the attributes attached to an element, as returned by the attributes
236    * attribute of the <code>Node</code> interface. If so, an attribute
237    * immediately appears containing the default value as well as the
238    * corresponding namespace URI, local name, and prefix when applicable.
239    * <br>HTML-only DOM implementations do not need to implement this method.
240    * 
241    * @param namespaceURI The namespace URI of the node to remove.
242    * @param localName The local name of the node to remove.
243    *
244    * @return The node removed from this map if a node with such a local
245    *   name and namespace URI exists.
246    * @exception DOMException
247    *   NOT_FOUND_ERR: Raised if there is no node with the specified
248    *   <code>namespaceURI</code> and <code>localName</code> in this map.
249    *   <br>NO_MODIFICATION_ALLOWED_ERR: Raised if this map is readonly.
250    * @since DOM Level 2
251    */
252   public Node   removeNamedItemNS(String   namespaceURI, String   localName)
253           throws DOMException  
254   {
255     throw new DTMException(DTMException.NO_MODIFICATION_ALLOWED_ERR);
256   }
257 
258   /**
259    * Simple implementation of DOMException.
260    * @xsl.usage internal
261    */
262   public class DTMException extends org.w3c.dom.DOMException  
263   {
264 
265     /**
266      * Constructs a DOM/DTM exception.
267      *
268      * @param code
269      * @param message
270      */
271     public DTMException(short code, String   message)
272     {
273       super(code, message);
274     }
275 
276     /**
277      * Constructor DTMException
278      *
279      *
280      * @param code
281      */
282     public DTMException(short code)
283     {
284       super(code, "");
285     }
286   }
287 }
288
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