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12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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15   * accompanied this code).
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25  
26  package javax.xml.namespace;
27  
28  import java.util.Iterator;
29  
30  /**
31   * <p>Interface for read only XML Namespace context processing.</p>
32   *
33   * <p>An XML Namespace has the properties:</p>
34   * <ul>
35   *   <li>Namespace URI:
36   *       Namespace name expressed as a URI to which the prefix is bound</li>
37   *   <li>prefix: syntactically, this is the part of the attribute name
38   *       following the <code>XMLConstants.XMLNS_ATTRIBUTE</code>
39   *       ("xmlns") in the Namespace declaration</li>
40   * </ul>
41   * <p>example:
42   * <code>&lt;element xmlns:prefix="http://Namespace-name-URI"&gt;</code></p>
43   *
44   * <p>All <code>get*(*)</code> methods operate in the current scope
45   * for Namespace URI and prefix resolution.</p>
46   *
47   * <p>Note that a Namespace URI can be bound to
48   * <strong>multiple</strong> prefixes in the current scope.  This can
49   * occur when multiple <code>XMLConstants.XMLNS_ATTRIBUTE</code>
50   * ("xmlns") Namespace declarations occur in the same Start-Tag and
51   * refer to the same Namespace URI. e.g.<br />
52   * <pre>
53   * &lt;element xmlns:prefix1="http://Namespace-name-URI"
54   *          xmlns:prefix2="http://Namespace-name-URI"&gt;
55   * </pre>
56   * This can also occur when the same Namespace URI is used in multiple
57   * <code>XMLConstants.XMLNS_ATTRIBUTE</code> ("xmlns") Namespace
58   * declarations in the logical parent element hierarchy.  e.g.<br />
59   * <pre>
60   * &lt;parent xmlns:prefix1="http://Namespace-name-URI">
61   *   &lt;child xmlns:prefix2="http://Namespace-name-URI"&gt;
62   *     ...
63   *   &lt;/child&gt;
64   * &lt;/parent&gt;
65   * </pre></p>
66   *
67   * <p>A prefix can only be bound to a <strong>single</strong>
68   * Namespace URI in the current scope.</p>
69   *
70   * @author <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>
71   * @see javax.xml.XMLConstants
72   *   javax.xml.XMLConstants for declarations of common XML values
73   * @see <a href="http://www.w3.org/TR/xmlschema-2/#QName">
74   *   XML Schema Part2: Datatypes</a>
75   * @see <a href="http://www.w3.org/TR/REC-xml-names/#ns-qualnames">
76   *   Namespaces in XML</a>
77   * @see <a href="http://www.w3.org/XML/xml-names-19990114-errata">
78   *   Namespaces in XML Errata</a>
79   * @since 1.5
80   */
81  
82  public interface NamespaceContext {
83  
84      /**
85       * <p>Get Namespace URI bound to a prefix in the current scope.</p>
86       *
87       * <p>When requesting a Namespace URI by prefix, the following
88       * table describes the returned Namespace URI value for all
89       * possible prefix values:</p>
90       *
91       * <table border="2" rules="all" cellpadding="4">
92       *   <thead>
93       *     <tr>
94       *       <td align="center" colspan="2">
95       *         <code>getNamespaceURI(prefix)</code>
96       *         return value for specified prefixes
97       *       </td>
98       *     </tr>
99       *     <tr>
100      *       <td>prefix parameter</td>
101      *       <td>Namespace URI return value</td>
102      *     </tr>
103      *   </thead>
104      *   <tbody>
105      *     <tr>
106      *       <td><code>DEFAULT_NS_PREFIX</code> ("")</td>
107      *       <td>default Namespace URI in the current scope or
108      *         <code>{@link
109      *         javax.xml.XMLConstants#NULL_NS_URI XMLConstants.NULL_NS_URI("")}
110      *         </code>
111      *         when there is no default Namespace URI in the current scope</td>
112      *     </tr>
113      *     <tr>
114      *       <td>bound prefix</td>
115      *       <td>Namespace URI bound to prefix in current scope</td>
116      *     </tr>
117      *     <tr>
118      *       <td>unbound prefix</td>
119      *       <td>
120      *         <code>{@link
121      *         javax.xml.XMLConstants#NULL_NS_URI XMLConstants.NULL_NS_URI("")}
122      *         </code>
123      *       </td>
124      *     </tr>
125      *     <tr>
126      *       <td><code>XMLConstants.XML_NS_PREFIX</code> ("xml")</td>
127      *       <td><code>XMLConstants.XML_NS_URI</code>
128      *           ("http://www.w3.org/XML/1998/namespace")</td>
129      *     </tr>
130      *     <tr>
131      *       <td><code>XMLConstants.XMLNS_ATTRIBUTE</code> ("xmlns")</td>
132      *       <td><code>XMLConstants.XMLNS_ATTRIBUTE_NS_URI</code>
133      *         ("http://www.w3.org/2000/xmlns/")</td>
134      *     </tr>
135      *     <tr>
136      *       <td><code>null</code></td>
137      *       <td><code>IllegalArgumentException</code> is thrown</td>
138      *     </tr>
139      *    </tbody>
140      * </table>
141      *
142      * @param prefix prefix to look up
143      *
144      * @return Namespace URI bound to prefix in the current scope
145      *
146      * @throws IllegalArgumentException When <code>prefix</code> is
147      *   <code>null</code>
148      */
149     String getNamespaceURI(String prefix);
150 
151     /**
152      * <p>Get prefix bound to Namespace URI in the current scope.</p>
153      *
154      * <p>To get all prefixes bound to a Namespace URI in the current
155      * scope, use {@link #getPrefixes(String namespaceURI)}.</p>
156      *
157      * <p>When requesting a prefix by Namespace URI, the following
158      * table describes the returned prefix value for all Namespace URI
159      * values:</p>
160      *
161      * <table border="2" rules="all" cellpadding="4">
162      *   <thead>
163      *     <tr>
164      *       <th align="center" colspan="2">
165      *         <code>getPrefix(namespaceURI)</code> return value for
166      *         specified Namespace URIs
167      *       </th>
168      *     </tr>
169      *     <tr>
170      *       <th>Namespace URI parameter</th>
171      *       <th>prefix value returned</th>
172      *     </tr>
173      *   </thead>
174      *   <tbody>
175      *     <tr>
176      *       <td>&lt;default Namespace URI&gt;</td>
177      *       <td><code>XMLConstants.DEFAULT_NS_PREFIX</code> ("")
178      *       </td>
179      *     </tr>
180      *     <tr>
181      *       <td>bound Namespace URI</td>
182      *       <td>prefix bound to Namespace URI in the current scope,
183      *           if multiple prefixes are bound to the Namespace URI in
184      *           the current scope, a single arbitrary prefix, whose
185      *           choice is implementation dependent, is returned</td>
186      *     </tr>
187      *     <tr>
188      *       <td>unbound Namespace URI</td>
189      *       <td><code>null</code></td>
190      *     </tr>
191      *     <tr>
192      *       <td><code>XMLConstants.XML_NS_URI</code>
193      *           ("http://www.w3.org/XML/1998/namespace")</td>
194      *       <td><code>XMLConstants.XML_NS_PREFIX</code> ("xml")</td>
195      *     </tr>
196      *     <tr>
197      *       <td><code>XMLConstants.XMLNS_ATTRIBUTE_NS_URI</code>
198      *           ("http://www.w3.org/2000/xmlns/")</td>
199      *       <td><code>XMLConstants.XMLNS_ATTRIBUTE</code> ("xmlns")</td>
200      *     </tr>
201      *     <tr>
202      *       <td><code>null</code></td>
203      *       <td><code>IllegalArgumentException</code> is thrown</td>
204      *     </tr>
205      *   </tbody>
206      * </table>
207      *
208      * @param namespaceURI URI of Namespace to lookup
209      *
210      * @return prefix bound to Namespace URI in current context
211      *
212      * @throws IllegalArgumentException When <code>namespaceURI</code> is
213      *   <code>null</code>
214      */
215     String getPrefix(String namespaceURI);
216 
217     /**
218      * <p>Get all prefixes bound to a Namespace URI in the current
219      * scope.</p>
220      *
221      * <p>An Iterator over String elements is returned in an arbitrary,
222      * <strong>implementation dependent</strong>, order.</p>
223      *
224      * <p><strong>The <code>Iterator</code> is
225      * <em>not</em> modifiable.  e.g. the
226      * <code>remove()</code> method will throw
227      * <code>UnsupportedOperationException</code>.</strong></p>
228      *
229      * <p>When requesting prefixes by Namespace URI, the following
230      * table describes the returned prefixes value for all Namespace
231      * URI values:</p>
232      *
233      * <table border="2" rules="all" cellpadding="4">
234      *   <thead>
235      *     <tr>
236      *       <th align="center" colspan="2"><code>
237      *         getPrefixes(namespaceURI)</code> return value for
238      *         specified Namespace URIs</th>
239      *     </tr>
240      *     <tr>
241      *       <th>Namespace URI parameter</th>
242      *       <th>prefixes value returned</th>
243      *     </tr>
244      *   </thead>
245      *   <tbody>
246      *     <tr>
247      *       <td>bound Namespace URI,
248      *         including the &lt;default Namespace URI&gt;</td>
249      *       <td>
250      *         <code>Iterator</code> over prefixes bound to Namespace URI in
251      *         the current scope in an arbitrary,
252      *         <strong>implementation dependent</strong>,
253      *         order
254      *       </td>
255      *     </tr>
256      *     <tr>
257      *       <td>unbound Namespace URI</td>
258      *       <td>empty <code>Iterator</code></td>
259      *     </tr>
260      *     <tr>
261      *       <td><code>XMLConstants.XML_NS_URI</code>
262      *           ("http://www.w3.org/XML/1998/namespace")</td>
263      *       <td><code>Iterator</code> with one element set to
264      *         <code>XMLConstants.XML_NS_PREFIX</code> ("xml")</td>
265      *     </tr>
266      *     <tr>
267      *       <td><code>XMLConstants.XMLNS_ATTRIBUTE_NS_URI</code>
268      *           ("http://www.w3.org/2000/xmlns/")</td>
269      *       <td><code>Iterator</code> with one element set to
270      *         <code>XMLConstants.XMLNS_ATTRIBUTE</code> ("xmlns")</td>
271      *     </tr>
272      *     <tr>
273      *       <td><code>null</code></td>
274      *       <td><code>IllegalArgumentException</code> is thrown</td>
275      *     </tr>
276      *   </tbody>
277      * </table>
278      *
279      * @param namespaceURI URI of Namespace to lookup
280      *
281      * @return <code>Iterator</code> for all prefixes bound to the
282      *   Namespace URI in the current scope
283      *
284      * @throws IllegalArgumentException When <code>namespaceURI</code> is
285      *   <code>null</code>
286      */
287     Iterator getPrefixes(String namespaceURI);
288 }