1 /*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5 /*
6 * Licensed to the Apache Software Foundation (ASF) under one or more
7 * contributor license agreements. See the NOTICE file distributed with
8 * this work for additional information regarding copyright ownership.
9 * The ASF licenses this file to You under the Apache License, Version 2.0
10 * (the "License"); you may not use this file except in compliance with
11 * the License. You may obtain a copy of the License at
12 *
13 * http://www.apache.org/licenses/LICENSE-2.0
14 *
15 * Unless required by applicable law or agreed to in writing, software
16 * distributed under the License is distributed on an "AS IS" BASIS,
17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18 * See the License for the specific language governing permissions and
19 * limitations under the License.
20 */
21
22 package com.sun.org.apache.xerces.internal.impl.dtd.models;
23
24 import com.sun.org.apache.xerces.internal.xni.QName;
25
26 import com.sun.org.apache.xerces.internal.impl.dtd.XMLContentSpec;
27
28 /**
29 * SimpleContentModel is a derivative of the abstract content model base
30 * class that handles a small set of simple content models that are just
31 * way overkill to give the DFA treatment.
32 * <p>
33 * This class handles the following scenarios:
34 * <ul>
35 * <li> a
36 * <li> a?
37 * <li> a*
38 * <li> a+
39 * <li> a,b
40 * <li> a|b
41 * </ul>
42 * <p>
43 * These all involve a unary operation with one element type, or a binary
44 * operation with two elements. These are very simple and can be checked
45 * in a simple way without a DFA and without the overhead of setting up a
46 * DFA for such a simple check.
47 *
48 * @xerces.internal
49 *
50 */
51 public class SimpleContentModel
52 implements ContentModelValidator {
53
54 //
55 // Constants
56 //
57
58 /** CHOICE */
59 public static final short CHOICE = -1;
60
61 /** SEQUENCE */
62 public static final short SEQUENCE = -1;
63
64 //
65 // Data
66 //
67
68
69 /**
70 * The element decl pool indices of the first (and optional second)
71 * child node. The operation code tells us whether the second child
72 * is used or not.
73 */
74 private QName fFirstChild = new QName();
75
76 /**
77 * The element decl pool indices of the first (and optional second)
78 * child node. The operation code tells us whether the second child
79 * is used or not.
80 */
81 private QName fSecondChild = new QName();
82
83 /**
84 * The operation that this object represents. Since this class only
85 * does simple contents, there is only ever a single operation
86 * involved (i.e. the children of the operation are always one or
87 * two leafs.) This is one of the XMLDTDParams.CONTENTSPECNODE_XXX values.
88 */
89 private int fOperator;
90
91 /* this is the EquivClassComparator object */
92 //private EquivClassComparator comparator = null;
93
94
95 //
96 // Constructors
97 //
98
99 /**
100 * Constructs a simple content model.
101 *
102 * @param operator The content model operator.
103 * @param firstChild qualified name of the first child
104 * @param secondChild qualified name of the second child
105 *
106 */
107 public SimpleContentModel(short operator, QName firstChild, QName secondChild) {
108 //
109 // Store away the children and operation. This is all we need to
110 // do the content model check.
111 //
112 // The operation is one of the ContentSpecNode.NODE_XXX values!
113 //
114 fFirstChild.setValues(firstChild);
115 if (secondChild != null) {
116 fSecondChild.setValues(secondChild);
117 }
118 else {
119 fSecondChild.clear();
120 }
121 fOperator = operator;
122 }
123
124 //
125 // ContentModelValidator methods
126 //
127
128 /**
129 * Check that the specified content is valid according to this
130 * content model. This method can also be called to do 'what if'
131 * testing of content models just to see if they would be valid.
132 * <p>
133 * A value of -1 in the children array indicates a PCDATA node. All other
134 * indexes will be positive and represent child elements. The count can be
135 * zero, since some elements have the EMPTY content model and that must be
136 * confirmed.
137 *
138 * @param children The children of this element. Each integer is an index within
139 * the <code>StringPool</code> of the child element name. An index
140 * of -1 is used to indicate an occurrence of non-whitespace character
141 * data.
142 * @param offset Offset into the array where the children starts.
143 * @param length The number of entries in the <code>children</code> array.
144 *
145 * @return The value -1 if fully valid, else the 0 based index of the child
146 * that first failed. If the value returned is equal to the number
147 * of children, then the specified children are valid but additional
148 * content is required to reach a valid ending state.
149 *
150 */
151 public int validate(QName[] children, int offset, int length) {
152
153 //
154 // According to the type of operation, we do the correct type of
155 // content check.
156 //
157 switch(fOperator)
158 {
159 case XMLContentSpec.CONTENTSPECNODE_LEAF :
160 // If there is not a child, then report an error at index 0
161 if (length == 0)
162 return 0;
163
164 // If the 0th child is not the right kind, report an error at 0
165 if (children[offset].rawname != fFirstChild.rawname) {
166 return 0;
167 }
168
169 // If more than one child, report an error at index 1
170 if (length > 1)
171 return 1;
172 break;
173
174 case XMLContentSpec.CONTENTSPECNODE_ZERO_OR_ONE :
175 //
176 // If there is one child, make sure its the right type. If not,
177 // then its an error at index 0.
178 //
179 if (length == 1) {
180 if (children[offset].rawname != fFirstChild.rawname) {
181 return 0;
182 }
183 }
184
185 //
186 // If the child count is greater than one, then obviously
187 // bad, so report an error at index 1.
188 //
189 if (length > 1)
190 return 1;
191 break;
192
193 case XMLContentSpec.CONTENTSPECNODE_ZERO_OR_MORE :
194 //
195 // If the child count is zero, that's fine. If its more than
196 // zero, then make sure that all children are of the element
197 // type that we stored. If not, report the index of the first
198 // failed one.
199 //
200 if (length > 0)
201 {
202 for (int index = 0; index < length; index++) {
203 if (children[offset + index].rawname != fFirstChild.rawname) {
204 return index;
205 }
206 }
207 }
208 break;
209
210 case XMLContentSpec.CONTENTSPECNODE_ONE_OR_MORE :
211 //
212 // If the child count is zero, that's an error so report
213 // an error at index 0.
214 //
215 if (length == 0)
216 return 0;
217
218 //
219 // Otherwise we have to check them all to make sure that they
220 // are of the correct child type. If not, then report the index
221 // of the first one that is not.
222 //
223 for (int index = 0; index < length; index++) {
224 if (children[offset + index].rawname != fFirstChild.rawname) {
225 return index;
226 }
227 }
228 break;
229
230 case XMLContentSpec.CONTENTSPECNODE_CHOICE :
231 //
232 // There must be one and only one child, so if the element count
233 // is zero, return an error at index 0.
234 //
235 if (length == 0)
236 return 0;
237
238 // If the zeroth element isn't one of our choices, error at 0
239 if ((children[offset].rawname != fFirstChild.rawname) &&
240 (children[offset].rawname != fSecondChild.rawname)) {
241 return 0;
242 }
243
244 // If there is more than one element, then an error at 1
245 if (length > 1)
246 return 1;
247 break;
248
249 case XMLContentSpec.CONTENTSPECNODE_SEQ :
250 //
251 // There must be two children and they must be the two values
252 // we stored, in the stored order.
253 //
254 if (length == 2) {
255 if (children[offset].rawname != fFirstChild.rawname) {
256 return 0;
257 }
258 if (children[offset + 1].rawname != fSecondChild.rawname) {
259 return 1;
260 }
261 }
262 else {
263 if (length > 2) {
264 return 2;
265 }
266
267 return length;
268 }
269
270 break;
271
272 default :
273 throw new RuntimeException("ImplementationMessages.VAL_CST");
274 }
275
276 // We survived, so return success status
277 return -1;
278 } // validate
279
280 } // class SimpleContentModel