1 /**
2 * Copyright (c) 2001, Thai Open Source Software Center Ltd
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met:
8 *
9 * Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in
14 * the documentation and/or other materials provided with the
15 * distribution.
16 *
17 * Neither the name of the Thai Open Source Software Center Ltd nor
18 * the names of its contributors may be used to endorse or promote
19 * products derived from this software without specific prior written
20 * permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
25 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR
26 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
27 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
28 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
29 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
30 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
31 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
32 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34 package org.relaxng.datatype;
35
36 /**
37 * Datatype object.
38 *
39 * This object has the following functionality:
40 *
41 * <ol>
42 * <li> functionality to identify a class of character sequences. This is
43 * done through the isValid method.
44 *
45 * <li> functionality to produce a "value object" from a character sequence and
46 * context information.
47 *
48 * <li> functionality to test the equality of two value objects.
49 * </ol>
50 *
51 * This interface also defines the createStreamingValidator method,
52 * which is intended to efficiently support the validation of
53 * large character sequences.
54 *
55 * @author <a href="mailto:jjc@jclark.com">James Clark</a>
56 * @author <a href="mailto:kohsuke.kawaguchi@sun.com">Kohsuke KAWAGUCHI</a>
57 */
58 public interface Datatype {
59
60 /**
61 * Checks if the specified 'literal' matches this Datatype
62 * with respect to the current context.
63 *
64 * @param literal
65 * the lexical representation to be checked.
66 * @param context
67 * If this datatype is context-dependent
68 * (i.e. the {@link #isContextDependent} method returns true),
69 * then the caller must provide a non-null valid context object.
70 * Otherwise, the caller can pass null.
71 *
72 * @return
73 * true if the 'literal' is a member of this Datatype;
74 * false if it's not a member of this Datatype.
75 */
76 boolean isValid( String literal, ValidationContext context );
77
78 /**
79 * Similar to the isValid method but throws an exception with diagnosis
80 * in case of errors.
81 *
82 * <p>
83 * If the specified 'literal' is a valid lexical representation for this
84 * datatype, then this method must return without throwing any exception.
85 * If not, the callee must throw an exception (with diagnosis message,
86 * if possible.)
87 *
88 * <p>
89 * The application can use this method to provide detailed error message
90 * to users. This method is kept separate from the isValid method to
91 * achieve higher performance during normal validation.
92 *
93 * @exception DatatypeException
94 * If the given literal is invalid, then this exception is thrown.
95 * If the callee supports error diagnosis, then the exception should
96 * contain a diagnosis message.
97 */
98 void checkValid( String literal, ValidationContext context )
99 throws DatatypeException;
100
101 /**
102 * Creates an instance of a streaming validator for this type.
103 *
104 * <p>
105 * By using streaming validators instead of the isValid method,
106 * the caller can avoid keeping the entire string, which is
107 * sometimes quite big, in memory.
108 *
109 * @param context
110 * If this datatype is context-dependent
111 * (i.e. the {@link #isContextDependent} method returns true),
112 * then the caller must provide a non-null valid context object.
113 * Otherwise, the caller can pass null.
114 * The callee may keep a reference to this context object
115 * only while the returned streaming validator is being used.
116 */
117 DatatypeStreamingValidator createStreamingValidator( ValidationContext context );
118
119 /**
120 * Converts lexcial value and the current context to the corresponding
121 * value object.
122 *
123 * <p>
124 * The caller cannot generally assume that the value object is
125 * a meaningful Java object. For example, the caller cannot expect
126 * this method to return <code>java.lang.Number</code> type for
127 * the "integer" type of XML Schema Part 2.
128 *
129 * <p>
130 * Also, the caller cannot assume that the equals method and
131 * the hashCode method of the value object are consistent with
132 * the semantics of the datatype. For that purpose, the sameValue
133 * method and the valueHashCode method have to be used. Note that
134 * this means you cannot use classes like
135 * <code>java.util.Hashtable</code> to store the value objects.
136 *
137 * <p>
138 * The returned value object should be used solely for the sameValue
139 * and valueHashCode methods.
140 *
141 * @param context
142 * If this datatype is context-dependent
143 * (when the {@link #isContextDependent} method returns true),
144 * then the caller must provide a non-null valid context object.
145 * Otherwise, the caller can pass null.
146 *
147 * @return null
148 * when the given lexical value is not a valid lexical
149 * value for this type.
150 */
151 Object createValue( String literal, ValidationContext context );
152
153 /**
154 * Tests the equality of two value objects which were originally
155 * created by the createValue method of this object.
156 *
157 * The behavior is undefined if objects not created by this type
158 * are passed. It is the caller's responsibility to ensure that
159 * value objects belong to this type.
160 *
161 * @return
162 * true if two value objects are considered equal according to
163 * the definition of this datatype; false if otherwise.
164 */
165 boolean sameValue( Object value1, Object value2 );
166
167
168 /**
169 * Computes the hash code for a value object,
170 * which is consistent with the sameValue method.
171 *
172 * @return
173 * hash code for the specified value object.
174 */
175 int valueHashCode( Object value );
176
177
178
179
180 /**
181 * Indicates that the datatype doesn't have ID/IDREF semantics.
182 *
183 * This value is one of the possible return values of the
184 * {@link #getIdType} method.
185 */
186 public static final int ID_TYPE_NULL = 0;
187
188 /**
189 * Indicates that RELAX NG compatibility processors should
190 * treat this datatype as having ID semantics.
191 *
192 * This value is one of the possible return values of the
193 * {@link #getIdType} method.
194 */
195 public static final int ID_TYPE_ID = 1;
196
197 /**
198 * Indicates that RELAX NG compatibility processors should
199 * treat this datatype as having IDREF semantics.
200 *
201 * This value is one of the possible return values of the
202 * {@link #getIdType} method.
203 */
204 public static final int ID_TYPE_IDREF = 2;
205
206 /**
207 * Indicates that RELAX NG compatibility processors should
208 * treat this datatype as having IDREFS semantics.
209 *
210 * This value is one of the possible return values of the
211 * {@link #getIdType} method.
212 */
213 public static final int ID_TYPE_IDREFS = 3;
214
215 /**
216 * Checks if the ID/IDREF semantics is associated with this
217 * datatype.
218 *
219 * <p>
220 * This method is introduced to support the RELAX NG DTD
221 * compatibility spec. (Of course it's always free to use
222 * this method for other purposes.)
223 *
224 * <p>
225 * If you are implementing a datatype library and have no idea about
226 * the "RELAX NG DTD compatibility" thing, just return
227 * <code>ID_TYPE_NULL</code> is fine.
228 *
229 * @return
230 * If this datatype doesn't have any ID/IDREF semantics,
231 * it returns {@link #ID_TYPE_NULL}. If it has such a semantics
232 * (for example, XSD:ID, XSD:IDREF and comp:ID type), then
233 * it returns {@link #ID_TYPE_ID}, {@link #ID_TYPE_IDREF} or
234 * {@link #ID_TYPE_IDREFS}.
235 */
236 public int getIdType();
237
238
239 /**
240 * Checks if this datatype may need a context object for
241 * the validation.
242 *
243 * <p>
244 * The callee must return true even when the context
245 * is not always necessary. (For example, the "QName" type
246 * doesn't need a context object when validating unprefixed
247 * string. But nonetheless QName must return true.)
248 *
249 * <p>
250 * XSD's <code>string</code> and <code>short</code> types
251 * are examples of context-independent datatypes.
252 * Its <code>QName</code> and <code>ENTITY</code> types
253 * are examples of context-dependent datatypes.
254 *
255 * <p>
256 * When a datatype is context-independent, then
257 * the {@link #isValid} method, the {@link #checkValid} method,
258 * the {@link #createStreamingValidator} method and
259 * the {@link #createValue} method can be called without
260 * providing a context object.
261 *
262 * @return
263 * <b>true</b> if this datatype is context-dependent
264 * (it needs a context object sometimes);
265 *
266 * <b>false</b> if this datatype is context-<b>in</b>dependent
267 * (it never needs a context object).
268 */
269 public boolean isContextDependent();
270 }