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      1 /*
      2  * Licensed to the Apache Software Foundation (ASF) under one or more
      3  * contributor license agreements.  See the NOTICE file distributed with
      4  * this work for additional information regarding copyright ownership.
      5  * The ASF licenses this file to You under the Apache License, Version 2.0
      6  * (the "License"); you may not use this file except in compliance with
      7  * the License.  You may obtain a copy of the License at
      8  *
      9  *     http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  * Unless required by applicable law or agreed to in writing, software
     12  * distributed under the License is distributed on an "AS IS" BASIS,
     13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  * See the License for the specific language governing permissions and
     15  * limitations under the License.
     16  */
     17 
     18 // $Id: NamespaceContext.java 446598 2006-09-15 12:55:40Z jeremias $
     19 
     20 package javax.xml.namespace;
     21 
     22 import java.util.Iterator;
     23 
     24 /**
     25  * <p>Interface for read only XML Namespace context processing.</p>
     26  *
     27  * <p>An XML Namespace has the properties:</p>
     28  * <ul>
     29  *   <li>Namespace URI:
     30  *       Namespace name expressed as a URI to which the prefix is bound</li>
     31  *   <li>prefix: syntactically, this is the part of the attribute name
     32  *       following the <code>XMLConstants.XMLNS_ATTRIBUTE</code>
     33  *       ("xmlns") in the Namespace declaration</li>
     34  * </ul>
     35  * <p> example: <code>&lt;element xmlns:prefix="http://Namespace-name-URI"&gt;</code></p>
     36  *
     37  * <p>All <code>get*(*)</code> methods operate in the current scope
     38  * for Namespace URI and prefix resolution.</p>
     39  *
     40  * <p>Note that a Namespace URI can be bound to
     41  * <strong>multiple</strong> prefixes in the current scope.  This can
     42  * occur when multiple <code>XMLConstants.XMLNS_ATTRIBUTE</code>
     43  * ("xmlns") Namespace declarations occur in the same Start-Tag and
     44  * refer to the same Namespace URI. e.g.<br />
     45  * <pre>
     46  * &lt;element xmlns:prefix1="http://Namespace-name-URI"
     47  *          xmlns:prefix2="http://Namespace-name-URI"&gt;
     48  * </pre>
     49  * This can also occur when the same Namespace URI is used in multiple
     50  * <code>XMLConstants.XMLNS_ATTRIBUTE</code> ("xmlns") Namespace
     51  * declarations in the logical parent element hierarchy.  e.g.<br />
     52  * <pre>
     53  * &lt;parent xmlns:prefix1="http://Namespace-name-URI">
     54  *   &lt;child xmlns:prefix2="http://Namespace-name-URI"&gt;
     55  *     ...
     56  *   &lt;/child&gt;
     57  * &lt;/parent&gt;
     58  * </pre></p>
     59  *
     60  * <p>A prefix can only be bound to a <strong>single</strong>
     61  * Namespace URI in the current scope.</p>
     62  *
     63  * @author <a href="mailto:Jeff.Suttor (at) Sun.com">Jeff Suttor</a>
     64  * @version $Revision: 446598 $, $Date: 2006-09-15 05:55:40 -0700 (Fri, 15 Sep 2006) $
     65  * @see javax.xml.XMLConstants javax.XMLConstants for declarations of common XML values
     66  * @see <a href="http://www.w3.org/TR/xmlschema-2/#QName">XML Schema Part2: Datatypes</a>
     67  * @see <a href="http://www.w3.org/TR/REC-xml-names/#ns-qualnames">Namespaces in XML</a>
     68  * @see <a href="http://www.w3.org/XML/xml-names-19990114-errata">Namespaces in XML Errata</a>
     69  * @since 1.5
     70  */
     71 
     72 public interface NamespaceContext {
     73 
     74     /**
     75      * <p>Get Namespace URI bound to a prefix in the current scope.</p>
     76      *
     77      * <p>When requesting a Namespace URI by prefix, the following
     78      * table describes the returned Namespace URI value for all
     79      * possible prefix values:</p>
     80      *
     81      * <table border="2" rules="all" cellpadding="4">
     82      *   <thead>
     83      *     <tr>
     84      *       <td align="center" colspan="2">
     85      *         <code>getNamespaceURI(prefix)</code>
     86      *         return value for specified prefixes
     87      *       </td>
     88      *     </tr>
     89      *     <tr>
     90      *       <td>prefix parameter</td>
     91      *       <td>Namespace URI return value</td>
     92      *     </tr>
     93      *   </thead>
     94      *   <tbody>
     95      *     <tr>
     96      *       <td><code>DEFAULT_NS_PREFIX</code> ("")</td>
     97      *       <td>default Namespace URI in the current scope or
     98      *         <code>{@link javax.xml.XMLConstants#NULL_NS_URI XMLConstants.NULL_NS_URI("")}</code>
     99      *         when there is no default Namespace URI in the current scope</td>
    100      *     </tr>
    101      *     <tr>
    102      *       <td>bound prefix</td>
    103      *       <td>Namespace URI bound to prefix in current scope</td>
    104      *     </tr>
    105      *     <tr>
    106      *       <td>unbound prefix</td>
    107      *       <td><code>{@link javax.xml.XMLConstants#NULL_NS_URI XMLConstants.NULL_NS_URI("")}</code> </td>
    108      *     </tr>
    109      *     <tr>
    110      *       <td><code>XMLConstants.XML_NS_PREFIX</code> ("xml")</td>
    111      *       <td><code>XMLConstants.XML_NS_URI</code>
    112      *           ("http://www.w3.org/XML/1998/namespace")</td>
    113      *     </tr>
    114      *     <tr>
    115      *       <td><code>XMLConstants.XMLNS_ATTRIBUTE</code> ("xmlns")</td>
    116      *       <td><code>XMLConstants.XMLNS_ATTRIBUTE_NS_URI</code>
    117      *         ("http://www.w3.org/2000/xmlns/")</td>
    118      *     </tr>
    119      *     <tr>
    120      *       <td><code>null</code></td>
    121      *       <td><code>IllegalArgumentException</code> is thrown</td>
    122      *     </tr>
    123      *    </tbody>
    124      * </table>
    125      *
    126      * @param prefix prefix to look up
    127      * @return Namespace URI bound to prefix in the current scope
    128      */
    129     String getNamespaceURI(String prefix);
    130 
    131     /**
    132      * <p>Get prefix bound to Namespace URI in the current scope.</p>
    133      *
    134      * <p>To get all prefixes bound to a Namespace URI in the current
    135      * scope, use {@link #getPrefixes(String namespaceURI)}.</p>
    136      *
    137      * <p>When requesting a prefix by Namespace URI, the following
    138      * table describes the returned prefix value for all Namespace URI
    139      * values:</p>
    140      *
    141      * <table border="2" rules="all" cellpadding="4">
    142      *   <thead>
    143      *     <tr>
    144      *       <td align="center" colspan="2">
    145      *         <code>getPrefix(namespaceURI)</code> return value for
    146      *         specified Namespace URIs
    147      *       </td>
    148      *     </tr>
    149      *     <tr>
    150      *       <td>Namespace URI parameter</td>
    151      *       <td>prefix value returned</td>
    152      *     </tr>
    153      *   </thead>
    154      *   <tbody>
    155      *     <tr>
    156      *       <td>&lt;default Namespace URI&gt;</td>
    157      *       <td><code>XMLConstants.DEFAULT_NS_PREFIX</code> ("")
    158      *       </td>
    159      *     </tr>
    160      *     <tr>
    161      *       <td>bound Namespace URI</td>
    162      *       <td>prefix bound to Namespace URI in the current scope,
    163      *           if multiple prefixes are bound to the Namespace URI in
    164      *           the current scope, a single arbitrary prefix, whose
    165      *           choice is implementation dependent, is returned</td>
    166      *     </tr>
    167      *     <tr>
    168      *       <td>unbound Namespace URI</td>
    169      *       <td><code>null</code></td>
    170      *     </tr>
    171      *     <tr>
    172      *       <td><code>XMLConstants.XML_NS_URI</code>
    173      *           ("http://www.w3.org/XML/1998/namespace")</td>
    174      *       <td><code>XMLConstants.XML_NS_PREFIX</code> ("xml")</td>
    175      *     </tr>
    176      *     <tr>
    177      *       <td><code>XMLConstants.XMLNS_ATTRIBUTE_NS_URI</code>
    178      *           ("http://www.w3.org/2000/xmlns/")</td>
    179      *       <td><code>XMLConstants.XMLNS_ATTRIBUTE</code> ("xmlns")</td>
    180      *     </tr>
    181      *     <tr>
    182      *       <td><code>null</code></td>
    183      *       <td><code>IllegalArgumentException</code> is thrown</td>
    184      *     </tr>
    185      *   </tbody>
    186      * </table>
    187      *
    188      * @param namespaceURI URI of Namespace to lookup
    189      * @return prefix bound to Namespace URI in current context
    190      */
    191     String getPrefix(String namespaceURI);
    192 
    193     /**
    194      * <p>Get all prefixes bound to a Namespace URI in the current
    195      * scope.</p>
    196      *
    197      * <p>An Iterator over String elements is returned in an arbitrary, <strong>implementation dependent</strong>, order.</p>
    198      *
    199      * <p><strong>The <code>Iterator</code> is
    200      * <em>not</em> modifiable.  e.g. the
    201      * <code>remove()</code> method will throw
    202      * <code>UnsupportedOperationException</code>.</strong></p>
    203      *
    204      * <p>When requesting prefixes by Namespace URI, the following
    205      * table describes the returned prefixes value for all Namespace
    206      * URI values:</p>
    207      *
    208      * <table border="2" rules="all" cellpadding="4">
    209      *   <thead>
    210      *     <tr>
    211      *       <td align="center" colspan="2"><code>
    212      *         getPrefixes(namespaceURI)</code> return value for
    213      *         specified Namespace URIs</td>
    214      *     </tr>
    215      *     <tr>
    216      *       <td>Namespace URI parameter</td>
    217      *       <td>prefixes value returned</td>
    218      *     </tr>
    219      *   </thead>
    220      *   <tbody>
    221      *     <tr>
    222      *       <td>bound Namespace URI,
    223      *         including the &lt;default Namespace URI&gt;</td>
    224      *       <td><code>Iterator</code> over prefixes bound to Namespace URI in
    225      *         the current scope in an arbitrary, <strong>implementation dependent</strong>,
    226      *         order</td>
    227      *     </tr>
    228      *     <tr>
    229      *       <td>unbound Namespace URI</td>
    230      *       <td>empty <code>Iterator</code></td>
    231      *     </tr>
    232      *     <tr>
    233      *       <td><code>XMLConstants.XML_NS_URI</code>
    234      *           ("http://www.w3.org/XML/1998/namespace")</td>
    235      *       <td><code>Iterator</code> with one element set to
    236      *         <code>XMLConstants.XML_NS_PREFIX</code> ("xml")</td>
    237      *     </tr>
    238      *     <tr>
    239      *       <td><code>XMLConstants.XMLNS_ATTRIBUTE_NS_URI</code>
    240      *           ("http://www.w3.org/2000/xmlns/")</td>
    241      *       <td><code>Iterator</code> with one element set to
    242      *         <code>XMLConstants.XMLNS_ATTRIBUTE</code> ("xmlns")</td>
    243      *     </tr>
    244      *     <tr>
    245      *       <td><code>null</code></td>
    246      *       <td><code>IllegalArgumentException</code> is thrown</td>
    247      *     </tr>
    248      *   </tbody>
    249      * </table>
    250      *
    251      * @param namespaceURI URI of Namespace to lookup
    252      * @return <code>Iterator</code> for all prefixes bound to the
    253      * Namespace URI in the current scope
    254      */
    255     Iterator getPrefixes(String namespaceURI);
    256 }
    257