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 1.6 2002/01/30 20:52:22 dbrownell Exp $
5
6package org.xml.sax.helpers;
7
8import org.xml.sax.AttributeList;
9
10import java.util.Vector;
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55 *             that interface has been replaced by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 */
66public class AttributeListImpl implements AttributeList
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 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 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 name, String type, String 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 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 getName (int i)
218    {
219    if (i < 0) {
220        return null;
221    }
222    try {
223        return (String)names.elementAt(i);
224    } catch (ArrayIndexOutOfBoundsException 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 getType (int i)
241    {
242    if (i < 0) {
243        return null;
244    }
245    try {
246        return (String)types.elementAt(i);
247    } catch (ArrayIndexOutOfBoundsException 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 getValue (int i)
262    {
263    if (i < 0) {
264        return null;
265    }
266    try {
267        return (String)values.elementAt(i);
268    } catch (ArrayIndexOutOfBoundsException 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 getType (String 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     * @return the named attribute's value or null, if the attribute does not
294     *         exist.
295     * @see org.xml.sax.AttributeList#getValue(java.lang.String)
296     */
297    public String getValue (String name)
298    {
299    return getValue(names.indexOf(name));
300    }
301
302
303
304    ////////////////////////////////////////////////////////////////////
305    // Internal state.
306    ////////////////////////////////////////////////////////////////////
307
308    Vector names = new Vector();
309    Vector types = new Vector();
310    Vector values = new Vector();
311
312}
313
314// end of AttributeListImpl.java
315