1 /*
2 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
3 */
4 /*
5 * Licensed to the Apache Software Foundation (ASF) under one or more
6 * contributor license agreements. See the NOTICE file distributed with
7 * this work for additional information regarding copyright ownership.
8 * The ASF licenses this file to You under the Apache License, Version 2.0
9 * (the "License"); you may not use this file except in compliance with
10 * the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing, software
15 * distributed under the License is distributed on an "AS IS" BASIS,
16 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17 * See the License for the specific language governing permissions and
18 * limitations under the License.
19 */
20
21 package com.sun.org.apache.xerces.internal.xni;
22
23 import java.util.Enumeration;
24
25 /**
26 * Represents an interface to query namespace information.
27 * <p>
28 * The prefix and namespace must be identical references for equal strings, thus
29 * each string should be internalized (@see String.intern())
30 * or added to the <code>SymbolTable</code>
31 *
32 * @see <a href="../../../../../xerces2/com/sun/org/apache/xerces/internal/util/SymbolTable.html">
33 * com.sun.org.apache.xerces.internal.util.SymbolTable</a>
34 *
35 * @author Andy Clark, IBM
36 *
37 * @LastModified: Oct 2017
38 */
39 public interface NamespaceContext {
40
41 //
42 // Constants
43 //
44
45 /**
46 * The XML Namespace ("http://www.w3.org/XML/1998/namespace"). This is
47 * the Namespace URI that is automatically mapped to the "xml" prefix.
48 */
49 public final static String XML_URI = "http://www.w3.org/XML/1998/namespace".intern();
50
51 /**
52 * XML Information Set REC
53 * all namespace attributes (including those named xmlns,
54 * whose [prefix] property has no value) have a namespace URI of http://www.w3.org/2000/xmlns/
55 */
56 public final static String XMLNS_URI = "http://www.w3.org/2000/xmlns/".intern();
57
58 //
59 // NamespaceContext methods
60 //
61
62 /**
63 * Start a new Namespace context.
64 * <p>
65 * A new context should be pushed at the beginning
66 * of each XML element: the new context will automatically inherit
67 * the declarations of its parent context, but it will also keep
68 * track of which declarations were made within this context.
69 * <p>
70 *
71 * @see #popContext
72 */
73 public void pushContext();
74
75 /**
76 * Revert to the previous Namespace context.
77 * <p>
78 * The context should be popped at the end of each
79 * XML element. After popping the context, all Namespace prefix
80 * mappings that were previously in force are restored.
81 * <p>
82 * Users must not attempt to declare additional Namespace
83 * prefixes after popping a context, unless you push another
84 * context first.
85 *
86 * @see #pushContext
87 */
88 public void popContext();
89
90 /**
91 * Declare a Namespace prefix.
92 * <p>
93 * This method declares a prefix in the current Namespace
94 * context; the prefix will remain in force until this context
95 * is popped, unless it is shadowed in a descendant context.
96 * <p>
97 * Note that to declare a default Namespace, use the empty string.
98 * The prefixes "xml" and "xmlns" can't be rebound.
99 * <p>
100 * Note that you must <em>not</em> declare a prefix after
101 * you've pushed and popped another Namespace.
102 *
103 * @param prefix The prefix to declare, or null for the empty
104 * string.
105 * @param uri The Namespace URI to associate with the prefix.
106 *
107 * @return true if the prefix was legal, false otherwise
108 *
109 * @see #getURI
110 * @see #getDeclaredPrefixAt
111 */
112 public boolean declarePrefix(String prefix, String uri);
113
114
115 /**
116 * Look up a prefix and get the currently-mapped Namespace URI.
117 * <p>
118 * This method looks up the prefix in the current context. If no mapping
119 * is found, this methods will continue lookup in the parent context(s).
120 * Use the empty string ("") for the default Namespace.
121 *
122 * @param prefix The prefix to look up.
123 *
124 * @return The associated Namespace URI, or null if the prefix
125 * is undeclared in this context.
126 */
127 public String getURI(String prefix);
128
129 /**
130 * Look up a namespace URI and get one of the mapped prefix.
131 * <p>
132 * This method looks up the namespace URI in the current context.
133 * If more than one prefix is currently mapped to the same URI,
134 * this method will make an arbitrary selection
135 * If no mapping is found, this methods will continue lookup in the
136 * parent context(s).
137 *
138 * @param uri The namespace URI to look up.
139 *
140 * @return One of the associated prefixes, or null if the uri
141 * does not map to any prefix.
142 *
143 * @see #getPrefix
144 */
145 public String getPrefix(String uri);
146
147
148 /**
149 * Return a count of locally declared prefixes, including
150 * the default prefix if bound.
151 */
152 public int getDeclaredPrefixCount();
153
154 /**
155 * Returns the prefix at the specified index in the current context.
156 */
157 public String getDeclaredPrefixAt(int index);
158
159 /**
160 * Return an enumeration of all prefixes whose declarations are active
161 * in the current context. This includes declarations from parent contexts
162 * that have not been overridden.
163 * @return Enumeration
164 */
165 public Enumeration<String> getAllPrefixes();
166
167 /**
168 * Reset this Namespace support object for reuse.
169 *
170 * <p>It is necessary to invoke this method before reusing the
171 * Namespace support object for a new session.</p>
172 *
173 * <p>Note that implementations of this method need to ensure that
174 * the declaration of the prefixes "xmlns" and "xml" are available.</p>
175 */
176 public void reset();
177
178
179 } // interface NamespaceContext