1 /*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5 /*
6 * The Apache Software License, Version 1.1
7 *
8 *
9 * Copyright (c) 1999-2002 The Apache Software Foundation. All rights
10 * reserved.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 *
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in
21 * the documentation and/or other materials provided with the
22 * distribution.
23 *
24 * 3. The end-user documentation included with the redistribution,
25 * if any, must include the following acknowledgment:
26 * "This product includes software developed by the
27 * Apache Software Foundation (http://www.apache.org/)."
28 * Alternately, this acknowledgment may appear in the software itself,
29 * if and wherever such third-party acknowledgments normally appear.
30 *
31 * 4. The names "Xerces" and "Apache Software Foundation" must
32 * not be used to endorse or promote products derived from this
33 * software without prior written permission. For written
34 * permission, please contact apache@apache.org.
35 *
36 * 5. Products derived from this software may not be called "Apache",
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40 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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48 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
49 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
50 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 * ====================================================================
53 *
54 * This software consists of voluntary contributions made by many
55 * individuals on behalf of the Apache Software Foundation and was
56 * originally based on software copyright (c) 1999, International
57 * Business Machines, Inc., http://www.apache.org. For more
58 * information on the Apache Software Foundation, please see
59 * <http://www.apache.org/>.
60 */
61
62 package com.sun.org.apache.xerces.internal.impl.dtd.models;
63
64 import com.sun.org.apache.xerces.internal.xni.QName;
65
66 import com.sun.org.apache.xerces.internal.impl.dtd.XMLContentSpec;
67
68 /**
69 * SimpleContentModel is a derivative of the abstract content model base
70 * class that handles a small set of simple content models that are just
71 * way overkill to give the DFA treatment.
72 * <p>
73 * This class handles the following scenarios:
74 * <ul>
75 * <li> a
76 * <li> a?
77 * <li> a*
78 * <li> a+
79 * <li> a,b
80 * <li> a|b
81 * </ul>
82 * <p>
83 * These all involve a unary operation with one element type, or a binary
84 * operation with two elements. These are very simple and can be checked
85 * in a simple way without a DFA and without the overhead of setting up a
86 * DFA for such a simple check.
87 *
88 * @xerces.internal
89 *
90 */
91 public class SimpleContentModel
92 implements ContentModelValidator {
93
94 //
95 // Constants
96 //
97
98 /** CHOICE */
99 public static final short CHOICE = -1;
100
101 /** SEQUENCE */
102 public static final short SEQUENCE = -1;
103
104 //
105 // Data
106 //
107
108
109 /**
110 * The element decl pool indices of the first (and optional second)
111 * child node. The operation code tells us whether the second child
112 * is used or not.
113 */
114 private QName fFirstChild = new QName();
115
116 /**
117 * The element decl pool indices of the first (and optional second)
118 * child node. The operation code tells us whether the second child
119 * is used or not.
120 */
121 private QName fSecondChild = new QName();
122
123 /**
124 * The operation that this object represents. Since this class only
125 * does simple contents, there is only ever a single operation
126 * involved (i.e. the children of the operation are always one or
127 * two leafs.) This is one of the XMLDTDParams.CONTENTSPECNODE_XXX values.
128 */
129 private int fOperator;
130
131 /* this is the EquivClassComparator object */
132 //private EquivClassComparator comparator = null;
133
134
135 //
136 // Constructors
137 //
138
139 /**
140 * Constructs a simple content model.
141 *
142 * @param operator The content model operator.
143 * @param firstChild qualified name of the first child
144 * @param secondChild qualified name of the second child
145 *
146 */
147 public SimpleContentModel(short operator, QName firstChild, QName secondChild) {
148 //
149 // Store away the children and operation. This is all we need to
150 // do the content model check.
151 //
152 // The operation is one of the ContentSpecNode.NODE_XXX values!
153 //
154 fFirstChild.setValues(firstChild);
155 if (secondChild != null) {
156 fSecondChild.setValues(secondChild);
157 }
158 else {
159 fSecondChild.clear();
160 }
161 fOperator = operator;
162 }
163
164 //
165 // ContentModelValidator methods
166 //
167
168 /**
169 * Check that the specified content is valid according to this
170 * content model. This method can also be called to do 'what if'
171 * testing of content models just to see if they would be valid.
172 * <p>
173 * A value of -1 in the children array indicates a PCDATA node. All other
174 * indexes will be positive and represent child elements. The count can be
175 * zero, since some elements have the EMPTY content model and that must be
176 * confirmed.
177 *
178 * @param children The children of this element. Each integer is an index within
179 * the <code>StringPool</code> of the child element name. An index
180 * of -1 is used to indicate an occurrence of non-whitespace character
181 * data.
182 * @param offset Offset into the array where the children starts.
183 * @param length The number of entries in the <code>children</code> array.
184 *
185 * @return The value -1 if fully valid, else the 0 based index of the child
186 * that first failed. If the value returned is equal to the number
187 * of children, then the specified children are valid but additional
188 * content is required to reach a valid ending state.
189 *
190 */
191 public int validate(QName[] children, int offset, int length) {
192
193 //
194 // According to the type of operation, we do the correct type of
195 // content check.
196 //
197 switch(fOperator)
198 {
199 case XMLContentSpec.CONTENTSPECNODE_LEAF :
200 // If there is not a child, then report an error at index 0
201 if (length == 0)
202 return 0;
203
204 // If the 0th child is not the right kind, report an error at 0
205 if (children[offset].rawname != fFirstChild.rawname) {
206 return 0;
207 }
208
209 // If more than one child, report an error at index 1
210 if (length > 1)
211 return 1;
212 break;
213
214 case XMLContentSpec.CONTENTSPECNODE_ZERO_OR_ONE :
215 //
216 // If there is one child, make sure its the right type. If not,
217 // then its an error at index 0.
218 //
219 if (length == 1) {
220 if (children[offset].rawname != fFirstChild.rawname) {
221 return 0;
222 }
223 }
224
225 //
226 // If the child count is greater than one, then obviously
227 // bad, so report an error at index 1.
228 //
229 if (length > 1)
230 return 1;
231 break;
232
233 case XMLContentSpec.CONTENTSPECNODE_ZERO_OR_MORE :
234 //
235 // If the child count is zero, that's fine. If its more than
236 // zero, then make sure that all children are of the element
237 // type that we stored. If not, report the index of the first
238 // failed one.
239 //
240 if (length > 0)
241 {
242 for (int index = 0; index < length; index++) {
243 if (children[offset + index].rawname != fFirstChild.rawname) {
244 return index;
245 }
246 }
247 }
248 break;
249
250 case XMLContentSpec.CONTENTSPECNODE_ONE_OR_MORE :
251 //
252 // If the child count is zero, that's an error so report
253 // an error at index 0.
254 //
255 if (length == 0)
256 return 0;
257
258 //
259 // Otherwise we have to check them all to make sure that they
260 // are of the correct child type. If not, then report the index
261 // of the first one that is not.
262 //
263 for (int index = 0; index < length; index++) {
264 if (children[offset + index].rawname != fFirstChild.rawname) {
265 return index;
266 }
267 }
268 break;
269
270 case XMLContentSpec.CONTENTSPECNODE_CHOICE :
271 //
272 // There must be one and only one child, so if the element count
273 // is zero, return an error at index 0.
274 //
275 if (length == 0)
276 return 0;
277
278 // If the zeroth element isn't one of our choices, error at 0
279 if ((children[offset].rawname != fFirstChild.rawname) &&
280 (children[offset].rawname != fSecondChild.rawname)) {
281 return 0;
282 }
283
284 // If there is more than one element, then an error at 1
285 if (length > 1)
286 return 1;
287 break;
288
289 case XMLContentSpec.CONTENTSPECNODE_SEQ :
290 //
291 // There must be two children and they must be the two values
292 // we stored, in the stored order.
293 //
294 if (length == 2) {
295 if (children[offset].rawname != fFirstChild.rawname) {
296 return 0;
297 }
298 if (children[offset + 1].rawname != fSecondChild.rawname) {
299 return 1;
300 }
301 }
302 else {
303 if (length > 2) {
304 return 2;
305 }
306
307 return length;
308 }
309
310 break;
311
312 default :
313 throw new RuntimeException("ImplementationMessages.VAL_CST");
314 }
315
316 // We survived, so return success status
317 return -1;
318 } // validate
319
320 } // class SimpleContentModel