AttributeList.java revision f33eae7e84eb6d3b0f4e86b59605bb3de73009f3 
1// SAX Attribute List Interface.
2// http://www.saxproject.org
3// No warranty; no copyright -- use this as you will.
4// $Id: AttributeList.java,v 1.7 2004/04/26 17:34:34 dmegginson Exp $
5
6package org.xml.sax;
7
8/**
9 * Interface for an element's attribute specifications.
10 *
11 * <blockquote>
12 * <em>This module, both source code and documentation, is in the
13 * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
14 * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
15 * for further information.
16 * </blockquote>
17 *
18 * <p>This is the original SAX1 interface for reporting an element's
19 * attributes.  Unlike the new {@link org.xml.sax.Attributes Attributes}
20 * interface, it does not support Namespace-related information.</p>
21 *
22 * <p>When an attribute list is supplied as part of a
23 * {@link org.xml.sax.DocumentHandler#startElement startElement}
24 * event, the list will return valid results only during the
25 * scope of the event; once the event handler returns control
26 * to the parser, the attribute list is invalid.  To save a
27 * persistent copy of the attribute list, use the SAX1
28 * {@link org.xml.sax.helpers.AttributeListImpl AttributeListImpl}
29 * helper class.</p>
30 *
31 * <p>An attribute list includes only attributes that have been
32 * specified or defaulted: #IMPLIED attributes will not be included.</p>
33 *
34 * <p>There are two ways for the SAX application to obtain information
35 * from the AttributeList.  First, it can iterate through the entire
36 * list:</p>
37 *
38 * <pre>
39 * public void startElement (String name, AttributeList atts) {
40 *   for (int i = 0; i < atts.getLength(); i++) {
41 *     String name = atts.getName(i);
42 *     String type = atts.getType(i);
43 *     String value = atts.getValue(i);
44 *     [...]
45 *   }
46 * }
47 * </pre>
48 *
49 * <p>(Note that the result of getLength() will be zero if there
50 * are no attributes.)
51 *
52 * <p>As an alternative, the application can request the value or
53 * type of specific attributes:</p>
54 *
55 * <pre>
56 * public void startElement (String name, AttributeList atts) {
57 *   String identifier = atts.getValue("id");
58 *   String label = atts.getValue("label");
59 *   [...]
60 * }
61 * </pre>
62 *
63 * @deprecated This interface has been replaced by the SAX2
64 *             {@link org.xml.sax.Attributes Attributes}
65 *             interface, which includes Namespace support.
66 * @since SAX 1.0
67 * @author David Megginson
68 * @version 2.0.1 (sax2r2)
69 * @see org.xml.sax.DocumentHandler#startElement startElement
70 * @see org.xml.sax.helpers.AttributeListImpl AttributeListImpl
71 */
72public interface AttributeList {
73
74
75    ////////////////////////////////////////////////////////////////////
76    // Iteration methods.
77    ////////////////////////////////////////////////////////////////////
78
79
80    /**
81     * Return the number of attributes in this list.
82     *
83     * <p>The SAX parser may provide attributes in any
84     * arbitrary order, regardless of the order in which they were
85     * declared or specified.  The number of attributes may be
86     * zero.</p>
87     *
88     * @return The number of attributes in the list.
89     */
90    public abstract int getLength ();
91
92
93    /**
94     * Return the name of an attribute in this list (by position).
95     *
96     * <p>The names must be unique: the SAX parser shall not include the
97     * same attribute twice.  Attributes without values (those declared
98     * #IMPLIED without a value specified in the start tag) will be
99     * omitted from the list.</p>
100     *
101     * <p>If the attribute name has a namespace prefix, the prefix
102     * will still be attached.</p>
103     *
104     * @param i The index of the attribute in the list (starting at 0).
105     * @return The name of the indexed attribute, or null
106     *         if the index is out of range.
107     * @see #getLength
108     */
109    public abstract String getName (int i);
110
111
112    /**
113     * Return the type of an attribute in the list (by position).
114     *
115     * <p>The attribute type is one of the strings "CDATA", "ID",
116     * "IDREF", "IDREFS", "NMTOKEN", "NMTOKENS", "ENTITY", "ENTITIES",
117     * or "NOTATION" (always in upper case).</p>
118     *
119     * <p>If the parser has not read a declaration for the attribute,
120     * or if the parser does not report attribute types, then it must
121     * return the value "CDATA" as stated in the XML 1.0 Recommentation
122     * (clause 3.3.3, "Attribute-Value Normalization").</p>
123     *
124     * <p>For an enumerated attribute that is not a notation, the
125     * parser will report the type as "NMTOKEN".</p>
126     *
127     * @param i The index of the attribute in the list (starting at 0).
128     * @return The attribute type as a string, or
129     *         null if the index is out of range.
130     * @see #getLength
131     * @see #getType(java.lang.String)
132     */
133    public abstract String getType (int i);
134
135
136    /**
137     * Return the value of an attribute in the list (by position).
138     *
139     * <p>If the attribute value is a list of tokens (IDREFS,
140     * ENTITIES, or NMTOKENS), the tokens will be concatenated
141     * into a single string separated by whitespace.</p>
142     *
143     * @param i The index of the attribute in the list (starting at 0).
144     * @return The attribute value as a string, or
145     *         null if the index is out of range.
146     * @see #getLength
147     * @see #getValue(java.lang.String)
148     */
149    public abstract String getValue (int i);
150
151
152
153    ////////////////////////////////////////////////////////////////////
154    // Lookup methods.
155    ////////////////////////////////////////////////////////////////////
156
157
158    /**
159     * Return the type of an attribute in the list (by name).
160     *
161     * <p>The return value is the same as the return value for
162     * getType(int).</p>
163     *
164     * <p>If the attribute name has a namespace prefix in the document,
165     * the application must include the prefix here.</p>
166     *
167     * @param name The name of the attribute.
168     * @return The attribute type as a string, or null if no
169     *         such attribute exists.
170     * @see #getType(int)
171     */
172    public abstract String getType (String name);
173
174
175    /**
176     * Return the value of an attribute in the list (by name).
177     *
178     * <p>The return value is the same as the return value for
179     * getValue(int).</p>
180     *
181     * <p>If the attribute name has a namespace prefix in the document,
182     * the application must include the prefix here.</p>
183     *
184     * @param name the name of the attribute to return
185     * @return The attribute value as a string, or null if
186     *         no such attribute exists.
187     * @see #getValue(int)
188     */
189    public abstract String getValue (String name);
190
191}
192
193// end of AttributeList.java
194