001    // Attributes.java - attribute list with Namespace support
002    // http://www.saxproject.org
003    // Written by David Megginson
004    // NO WARRANTY!  This class is in the public domain.
005    // $Id: Attributes.java,v 1.1 2004/12/23 22:38:42 mark Exp $
006    
007    package org.xml.sax;
008    
009    
010    /**
011     * Interface for a list of XML attributes.
012     *
013     * <blockquote>
014     * <em>This module, both source code and documentation, is in the
015     * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
016     * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
017     * for further information.
018     * </blockquote>
019     *
020     * <p>This interface allows access to a list of attributes in
021     * three different ways:</p>
022     *
023     * <ol>
024     * <li>by attribute index;</li>
025     * <li>by Namespace-qualified name; or</li>
026     * <li>by qualified (prefixed) name.</li>
027     * </ol>
028     *
029     * <p>The list will not contain attributes that were declared
030     * #IMPLIED but not specified in the start tag.  It will also not
031     * contain attributes used as Namespace declarations (xmlns*) unless
032     * the <code>http://xml.org/sax/features/namespace-prefixes</code> 
033     * feature is set to <var>true</var> (it is <var>false</var> by 
034     * default).
035     * Because SAX2 conforms to the original "Namespaces in XML"
036     * recommendation, it normally does not
037     * give namespace declaration attributes a namespace URI.
038     * </p>
039     *
040     * <p>Some SAX2 parsers may support using an optional feature flag
041     * (<code>http://xml.org/sax/features/xmlns-uris</code>) to request
042     * that those attributes be given URIs, conforming to a later
043     * backwards-incompatible revision of that recommendation.  (The
044     * attribute's "local name" will be the prefix, or "xmlns" when
045     * defining a default element namespace.)  For portability, handler
046     * code should always resolve that conflict, rather than requiring
047     * parsers that can change the setting of that feature flag.  </p>
048     *
049     * <p>If the namespace-prefixes feature (see above) is
050     * <var>false</var>, access by qualified name may not be available; if
051     * the <code>http://xml.org/sax/features/namespaces</code> feature is
052     * <var>false</var>, access by Namespace-qualified names may not be
053     * available.</p>
054     *
055     * <p>This interface replaces the now-deprecated SAX1 {@link
056     * org.xml.sax.AttributeList AttributeList} interface, which does not 
057     * contain Namespace support.  In addition to Namespace support, it 
058     * adds the <var>getIndex</var> methods (below).</p>
059     *
060     * <p>The order of attributes in the list is unspecified, and will
061     * vary from implementation to implementation.</p>
062     *
063     * @since SAX 2.0
064     * @author David Megginson
065     * @version 2.0.1 (sax2r2)
066     * @see org.xml.sax.helpers.AttributesImpl
067     * @see org.xml.sax.ext.DeclHandler#attributeDecl
068     */
069    public interface Attributes
070    {
071    
072    
073        ////////////////////////////////////////////////////////////////////
074        // Indexed access.
075        ////////////////////////////////////////////////////////////////////
076    
077    
078        /**
079         * Return the number of attributes in the list.
080         *
081         * <p>Once you know the number of attributes, you can iterate
082         * through the list.</p>
083         *
084         * @return The number of attributes in the list.
085         * @see #getURI(int)
086         * @see #getLocalName(int)
087         * @see #getQName(int)
088         * @see #getType(int)
089         * @see #getValue(int)
090         */
091        public abstract int getLength ();
092    
093    
094        /**
095         * Look up an attribute's Namespace URI by index.
096         *
097         * @param index The attribute index (zero-based).
098         * @return The Namespace URI, or the empty string if none
099         *         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