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Java > Open Source Codes > org > xml > sax > helpers > AttributeListImpl


1 // SAX default implementation for AttributeList.
2 // http://www.saxproject.org
3 // No warranty; no copyright -- use this as you will.
4 // $Id: AttributeListImpl.java,v 1.1.24.1 2004/05/01 08:34:45 jsuttor Exp $
5
6 package org.xml.sax.helpers;
7
8 import org.xml.sax.AttributeList JavaDoc;
9
10 import java.util.Vector JavaDoc;
11
12
13 /**
14  * Default implementation for AttributeList.
15  *
16  * <blockquote>
17  * <em>This module, both source code and documentation, is in the
18  * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
19  * See <a HREF='http://www.saxproject.org'>http://www.saxproject.org</a>
20  * for further information.
21  * </blockquote>
22  *
23  * <p>AttributeList implements the deprecated SAX1 {@link
24  * org.xml.sax.AttributeList AttributeList} interface, and has been
25  * replaced by the new SAX2 {@link org.xml.sax.helpers.AttributesImpl
26  * AttributesImpl} interface.</p>
27  *
28  * <p>This class provides a convenience implementation of the SAX
29  * {@link org.xml.sax.AttributeList AttributeList} interface. This
30  * implementation is useful both for SAX parser writers, who can use
31  * it to provide attributes to the application, and for SAX application
32  * writers, who can use it to create a persistent copy of an element's
33  * attribute specifications:</p>
34  *
35  * <pre>
36  * private AttributeList myatts;
37  *
38  * public void startElement (String name, AttributeList atts)
39  * {
40  * // create a persistent copy of the attribute list
41  * // for use outside this method
42  * myatts = new AttributeListImpl(atts);
43  * [...]
44  * }
45  * </pre>
46  *
47  * <p>Please note that SAX parsers are not required to use this
48  * class to provide an implementation of AttributeList; it is
49  * supplied only as an optional convenience. In particular,
50  * parser writers are encouraged to invent more efficient
51  * implementations.</p>
52  *
53  * @deprecated This class implements a deprecated interface,
54  * {@link org.xml.sax.AttributeList AttributeList};
55  * that interface has been replaced by
56  * {@link org.xml.sax.Attributes Attributes},
57  * which is implemented in the
58  * {@link org.xml.sax.helpers.AttributesImpl
59  * AttributesImpl} helper class.
60  * @since SAX 1.0
61  * @author David Megginson
62  * @version 2.0.1 (sax2r2)
63  * @see org.xml.sax.AttributeList
64  * @see org.xml.sax.DocumentHandler#startElement
65  */
66 public class AttributeListImpl implements AttributeList JavaDoc
67 {
68     
69     /**
70      * Create an empty attribute list.
71      *
72      * <p>This constructor is most useful for parser writers, who
73      * will use it to create a single, reusable attribute list that
74      * can be reset with the clear method between elements.</p>
75      *
76      * @see #addAttribute
77      * @see #clear
78      */
79     public AttributeListImpl ()
80     {
81     }
82     
83     
84     /**
85      * Construct a persistent copy of an existing attribute list.
86      *
87      * <p>This constructor is most useful for application writers,
88      * who will use it to create a persistent copy of an existing
89      * attribute list.</p>
90      *
91      * @param atts The attribute list to copy
92      * @see org.xml.sax.DocumentHandler#startElement
93      */
94     public AttributeListImpl (AttributeList JavaDoc atts)
95     {
96     setAttributeList(atts);
97     }
98     
99     
100
101     ////////////////////////////////////////////////////////////////////
102 // Methods specific to this class.
103 ////////////////////////////////////////////////////////////////////
104
105     
106     /**
107      * Set the attribute list, discarding previous contents.
108      *
109      * <p>This method allows an application writer to reuse an
110      * attribute list easily.</p>
111      *
112      * @param atts The attribute list to copy.
113      */
114     public void setAttributeList (AttributeList JavaDoc atts)
115     {
116     int count = atts.getLength();
117     
118     clear();
119     
120     for (int i = 0; i < count; i++) {
121         addAttribute(atts.getName(i), atts.getType(i), atts.getValue(i));
122     }
123     }
124     
125     
126     /**
127      * Add an attribute to an attribute list.
128      *
129      * <p>This method is provided for SAX parser writers, to allow them
130      * to build up an attribute list incrementally before delivering
131      * it to the application.</p>
132      *
133      * @param name The attribute name.
134      * @param type The attribute type ("NMTOKEN" for an enumeration).
135      * @param value The attribute value (must not be null).
136      * @see #removeAttribute
137      * @see org.xml.sax.DocumentHandler#startElement
138      */
139     public void addAttribute (String JavaDoc name, String JavaDoc type, String JavaDoc value)
140     {
141     names.addElement(name);
142     types.addElement(type);
143     values.addElement(value);
144     }
145     
146     
147     /**
148      * Remove an attribute from the list.
149      *
150      * <p>SAX application writers can use this method to filter an
151      * attribute out of an AttributeList. Note that invoking this
152      * method will change the length of the attribute list and
153      * some of the attribute's indices.</p>
154      *
155      * <p>If the requested attribute is not in the list, this is
156      * a no-op.</p>
157      *
158      * @param name The attribute name.
159      * @see #addAttribute
160      */
161     public void removeAttribute (String JavaDoc name)
162     {
163     int i = names.indexOf(name);
164     
165     if (i >= 0) {
166         names.removeElementAt(i);
167         types.removeElementAt(i);
168         values.removeElementAt(i);
169     }
170     }
171     
172     
173     /**
174      * Clear the attribute list.
175      *
176      * <p>SAX parser writers can use this method to reset the attribute
177      * list between DocumentHandler.startElement events. Normally,
178      * it will make sense to reuse the same AttributeListImpl object
179      * rather than allocating a new one each time.</p>
180      *
181      * @see org.xml.sax.DocumentHandler#startElement
182      */
183     public void clear ()
184     {
185     names.removeAllElements();
186     types.removeAllElements();
187     values.removeAllElements();
188     }
189     
190     
191
192     ////////////////////////////////////////////////////////////////////
193 // Implementation of org.xml.sax.AttributeList
194 ////////////////////////////////////////////////////////////////////
195
196     
197     /**
198      * Return the number of attributes in the list.
199      *
200      * @return The number of attributes in the list.
201      * @see org.xml.sax.AttributeList#getLength
202      */
203     public int getLength ()
204     {
205     return names.size();
206     }
207     
208     
209     /**
210      * Get the name of an attribute (by position).
211      *
212      * @param i The position of the attribute in the list.
213      * @return The attribute name as a string, or null if there
214      * is no attribute at that position.
215      * @see org.xml.sax.AttributeList#getName(int)
216      */
217     public String JavaDoc getName (int i)
218     {
219     if (i < 0) {
220         return null;
221     }
222     try {
223         return (String JavaDoc)names.elementAt(i);
224     } catch (ArrayIndexOutOfBoundsException JavaDoc e) {
225         return null;
226     }
227     }
228     
229     
230     /**
231      * Get the type of an attribute (by position).
232      *
233      * @param i The position of the attribute in the list.
234      * @return The attribute type as a string ("NMTOKEN" for an
235      * enumeration, and "CDATA" if no declaration was
236      * read), or null if there is no attribute at
237      * that position.
238      * @see org.xml.sax.AttributeList#getType(int)
239      */
240     public String JavaDoc getType (int i)
241     {
242     if (i < 0) {
243         return null;
244     }
245     try {
246         return (String JavaDoc)types.elementAt(i);
247     } catch (ArrayIndexOutOfBoundsException JavaDoc e) {
248         return null;
249     }
250     }
251     
252     
253     /**
254      * Get the value of an attribute (by position).
255      *
256      * @param i The position of the attribute in the list.
257      * @return The attribute value as a string, or null if
258      * there is no attribute at that position.
259      * @see org.xml.sax.AttributeList#getValue(int)
260      */
261     public String JavaDoc getValue (int i)
262     {
263     if (i < 0) {
264         return null;
265     }
266     try {
267         return (String JavaDoc)values.elementAt(i);
268     } catch (ArrayIndexOutOfBoundsException JavaDoc e) {
269         return null;
270     }
271     }
272     
273     
274     /**
275      * Get the type of an attribute (by name).
276      *
277      * @param name The attribute name.
278      * @return The attribute type as a string ("NMTOKEN" for an
279      * enumeration, and "CDATA" if no declaration was
280      * read).
281      * @see org.xml.sax.AttributeList#getType(java.lang.String)
282      */
283     public String JavaDoc getType (String JavaDoc name)
284     {
285     return getType(names.indexOf(name));
286     }
287     
288     
289     /**
290      * Get the value of an attribute (by name).
291      *
292      * @param name The attribute name.
293      * @see org.xml.sax.AttributeList#getValue(java.lang.String)
294      */
295     public String JavaDoc getValue (String JavaDoc name)
296     {
297     return getValue(names.indexOf(name));
298     }
299     
300     
301
302     ////////////////////////////////////////////////////////////////////
303 // Internal state.
304 ////////////////////////////////////////////////////////////////////
305
306     Vector JavaDoc names = new Vector JavaDoc();
307     Vector JavaDoc types = new Vector JavaDoc();
308     Vector JavaDoc values = new Vector JavaDoc();
309
310 }
311
312 // end of AttributeListImpl.java
313
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