1 // Attributes.java - attribute list with Namespace support
2 // http://www.saxproject.org
3 // Written by David Megginson
4 // NO WARRANTY! This class is in the public domain.
5 // $Id: Attributes.java 226184 2005-04-08 10:53:24Z neeraj $
6
7 package org.xml.sax;
8
9
10 /**
11 * Interface for a list of XML attributes.
12 *
13 * <blockquote>
14 * <em>This module, both source code and documentation, is in the
15 * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
16 * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
17 * for further information.
18 * </blockquote>
19 *
20 * <p>This interface allows access to a list of attributes in
21 * three different ways:</p>
22 *
23 * <ol>
24 * <li>by attribute index;</li>
25 * <li>by Namespace-qualified name; or</li>
26 * <li>by qualified (prefixed) name.</li>
27 * </ol>
28 *
29 * <p>The list will not contain attributes that were declared
30 * #IMPLIED but not specified in the start tag. It will also not
31 * contain attributes used as Namespace declarations (xmlns*) unless
32 * the <code>http://xml.org/sax/features/namespace-prefixes</code>
33 * feature is set to <var>true</var> (it is <var>false</var> by
34 * default).
35 * Because SAX2 conforms to the original "Namespaces in XML"
36 * recommendation, it normally does not
37 * give namespace declaration attributes a namespace URI.
38 * </p>
39 *
40 * <p>Some SAX2 parsers may support using an optional feature flag
41 * (<code>http://xml.org/sax/features/xmlns-uris</code>) to request
42 * that those attributes be given URIs, conforming to a later
43 * backwards-incompatible revision of that recommendation. (The
44 * attribute's "local name" will be the prefix, or "xmlns" when
45 * defining a default element namespace.) For portability, handler
46 * code should always resolve that conflict, rather than requiring
47 * parsers that can change the setting of that feature flag. </p>
48 *
49 * <p>If the namespace-prefixes feature (see above) is
50 * <var>false</var>, access by qualified name may not be available; if
51 * the <code>http://xml.org/sax/features/namespaces</code> feature is
52 * <var>false</var>, access by Namespace-qualified names may not be
53 * available.</p>
54 *
55 * <p>This interface replaces the now-deprecated SAX1 {@link
56 * org.xml.sax.AttributeList AttributeList} interface, which does not
57 * contain Namespace support. In addition to Namespace support, it
58 * adds the <var>getIndex</var> methods (below).</p>
59 *
60 * <p>The order of attributes in the list is unspecified, and will
61 * vary from implementation to implementation.</p>
62 *
63 * @since SAX 2.0
64 * @author David Megginson
65 * @version 2.0.1 (sax2r2)
66 * @see org.xml.sax.helpers.AttributesImpl
67 * @see org.xml.sax.ext.DeclHandler#attributeDecl
68 */
69 public interface Attributes
70 {
71
72
73 ////////////////////////////////////////////////////////////////////
74 // Indexed access.
75 ////////////////////////////////////////////////////////////////////
76
77
78 /**
79 * Return the number of attributes in the list.
80 *
81 * <p>Once you know the number of attributes, you can iterate
82 * through the list.</p>
83 *
84 * @return The number of attributes in the list.
85 * @see #getURI(int)
86 * @see #getLocalName(int)
87 * @see #getQName(int)
88 * @see #getType(int)
89 * @see #getValue(int)
90 */
91 public abstract int getLength ();
92
93
94 /**
95 * Look up an attribute's Namespace URI by index.
96 *
97 * @param index The attribute index (zero-based).
98 * @return The Namespace URI, or the empty string if none
99 * is available, or null if the index is out of
100 * range.
101 * @see #getLength
102 */
103 public abstract String getURI (int index);
104
105
106 /**
107 * Look up an attribute's local name by index.
108 *
109 * @param index The attribute index (zero-based).
110 * @return The local name, or the empty string if Namespace
111 * processing is not being performed, or null
112 * if the index is out of range.
113 * @see #getLength
114 */
115 public abstract String getLocalName (int index);
116
117
118 /**
119 * Look up an attribute's XML qualified (prefixed) name by index.
120 *
121 * @param index The attribute index (zero-based).
122 * @return The XML qualified name, or the empty string
123 * if none is available, or null if the index
124 * is out of range.
125 * @see #getLength
126 */
127 public abstract String getQName (int index);
128
129
130 /**
131 * Look up an attribute's type by index.
132 *
133 * <p>The attribute type is one of the strings "CDATA", "ID",
134 * "IDREF", "IDREFS", "NMTOKEN", "NMTOKENS", "ENTITY", "ENTITIES",
135 * or "NOTATION" (always in upper case).</p>
136 *
137 * <p>If the parser has not read a declaration for the attribute,
138 * or if the parser does not report attribute types, then it must
139 * return the value "CDATA" as stated in the XML 1.0 Recommendation
140 * (clause 3.3.3, "Attribute-Value Normalization").</p>
141 *
142 * <p>For an enumerated attribute that is not a notation, the
143 * parser will report the type as "NMTOKEN".</p>
144 *
145 * @param index The attribute index (zero-based).
146 * @return The attribute's type as a string, or null if the
147 * index is out of range.
148 * @see #getLength
149 */
150 public abstract String getType (int index);
151
152
153 /**
154 * Look up an attribute's value by index.
155 *
156 * <p>If the attribute value is a list of tokens (IDREFS,
157 * ENTITIES, or NMTOKENS), the tokens will be concatenated
158 * into a single string with each token separated by a
159 * single space.</p>
160 *
161 * @param index The attribute index (zero-based).
162 * @return The attribute's value as a string, or null if the
163 * index is out of range.
164 * @see #getLength
165 */
166 public abstract String getValue (int index);
167
168
169
170 ////////////////////////////////////////////////////////////////////
171 // Name-based query.
172 ////////////////////////////////////////////////////////////////////
173
174
175 /**
176 * Look up the index of an attribute by Namespace name.
177 *
178 * @param uri The Namespace URI, or the empty string if
179 * the name has no Namespace URI.
180 * @param localName The attribute's local name.
181 * @return The index of the attribute, or -1 if it does not
182 * appear in the list.
183 */
184 public int getIndex (String uri, String localName);
185
186
187 /**
188 * Look up the index of an attribute by XML qualified (prefixed) name.
189 *
190 * @param qName The qualified (prefixed) name.
191 * @return The index of the attribute, or -1 if it does not
192 * appear in the list.
193 */
194 public int getIndex (String qName);
195
196
197 /**
198 * Look up an attribute's type by Namespace name.
199 *
200 * <p>See {@link #getType(int) getType(int)} for a description
201 * of the possible types.</p>
202 *
203 * @param uri The Namespace URI, or the empty String if the
204 * name has no Namespace URI.
205 * @param localName The local name of the attribute.
206 * @return The attribute type as a string, or null if the
207 * attribute is not in the list or if Namespace
208 * processing is not being performed.
209 */
210 public abstract String getType (String uri, String localName);
211
212
213 /**
214 * Look up an attribute's type by XML qualified (prefixed) name.
215 *
216 * <p>See {@link #getType(int) getType(int)} for a description
217 * of the possible types.</p>
218 *
219 * @param qName The XML qualified name.
220 * @return The attribute type as a string, or null if the
221 * attribute is not in the list or if qualified names
222 * are not available.
223 */
224 public abstract String getType (String qName);
225
226
227 /**
228 * Look up an attribute's value by Namespace name.
229 *
230 * <p>See {@link #getValue(int) getValue(int)} for a description
231 * of the possible values.</p>
232 *
233 * @param uri The Namespace URI, or the empty String if the
234 * name has no Namespace URI.
235 * @param localName The local name of the attribute.
236 * @return The attribute value as a string, or null if the
237 * attribute is not in the list.
238 */
239 public abstract String getValue (String uri, String localName);
240
241
242 /**
243 * Look up an attribute's value by XML qualified (prefixed) name.
244 *
245 * <p>See {@link #getValue(int) getValue(int)} for a description
246 * of the possible values.</p>
247 *
248 * @param qName The XML qualified name.
249 * @return The attribute value as a string, or null if the
250 * attribute is not in the list or if qualified names
251 * are not available.
252 */
253 public abstract String getValue (String qName);
254
255 }
256
257 // end of Attributes.java