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
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20 */
21
22package com.sun.org.apache.xerces.internal.impl.dtd;
23
24/**
25 * ContentSpec really exists to aid the parser classes in implementing
26 * access to the grammar.
27 * <p>
28 * This class is used by the DTD scanner and the validator classes,
29 * allowing them to be used separately or together.  This "struct"
30 * class is used to build content models for validation, where it
31 * is more efficient to fetch all of the information for each of
32 * these content model "fragments" than to fetch each field one at
33 * a time.  Since configurations are allowed to have validators
34 * without a DTD scanner (i.e. a schema validator) and a DTD scanner
35 * without a validator (non-validating processor), this class can be
36 * used by each without requiring the presence of the other.
37 * <p>
38 * When processing element declarations, the DTD scanner will build
39 * up a representation of the content model using the node types that
40 * are defined here.  Since a non-validating processor only needs to
41 * remember the type of content model declared (i.e. ANY, EMPTY, MIXED,
42 * or CHILDREN), it is free to discard the specific details of the
43 * MIXED and CHILDREN content models described using this class.
44 * <p>
45 * In the typical case of a validating processor reading the grammar
46 * of the document from a DTD, the information about the content model
47 * declared will be preserved and later "compiled" into an efficient
48 * form for use during element validation.  Each content spec node
49 * that is saved is assigned a unique index that is used as a handle
50 * for the "value" or "otherValue" fields of other content spec nodes.
51 * A leaf node has a "value" that is either an index in the string
52 * pool of the element type of that leaf, or a value of -1 to indicate
53 * the special "#PCDATA" leaf type used in a mixed content model.
54 * <p>
55 * For a mixed content model, the content spec will be made up of
56 * leaf and choice content spec nodes, with an optional "zero or more"
57 * node.  For example, the mixed content declaration "(#PCDATA)" would
58 * contain a single leaf node with a node value of -1.  A mixed content
59 * declaration of "(#PCDATA|foo)*" would have a content spec consisting
60 * of two leaf nodes, for the "#PCDATA" and "foo" choices, a choice node
61 * with the "value" set to the index of the "#PCDATA" leaf node and the
62 * "otherValue" set to the index of the "foo" leaf node, and a "zero or
63 * more" node with the "value" set to the index of the choice node.  If
64 * the content model has more choices, for example "(#PCDATA|a|b)*", then
65 * there will be more corresponding choice and leaf nodes, the choice
66 * nodes will be chained together through the "value" field with each
67 * leaf node referenced by the "otherValue" field.
68 * <p>
69 * For element content models, there are sequence nodes and also "zero or
70 * one" and "one or more" nodes.  The leaf nodes would always have a valid
71 * string pool index, as the "#PCDATA" leaf is not used in the declarations
72 * for element content models.
73 *
74 * @xerces.internal
75 *
76 */
77public class XMLContentSpec {
78
79    //
80    // Constants
81    //
82
83    /**
84     * Name or #PCDATA. Leaf nodes that represent parsed character
85     * data (#PCDATA) have values of -1.
86     */
87    public static final short CONTENTSPECNODE_LEAF = 0;
88
89    /** Represents a zero or one occurence count, '?'. */
90    public static final short CONTENTSPECNODE_ZERO_OR_ONE = 1;
91
92    /** Represents a zero or more occurence count, '*'. */
93    public static final short CONTENTSPECNODE_ZERO_OR_MORE = 2;
94
95    /** Represents a one or more occurence count, '+'. */
96    public static final short CONTENTSPECNODE_ONE_OR_MORE = 3;
97
98    /** Represents choice, '|'. */
99    public static final short CONTENTSPECNODE_CHOICE = 4;
100
101    /** Represents sequence, ','. */
102    public static final short CONTENTSPECNODE_SEQ = 5;
103
104    /**
105     * Represents any namespace specified namespace. When the element
106     * found in the document must belong to a specific namespace,
107     * <code>otherValue</code> will contain the name of the namespace.
108     * If <code>otherValue</code> is <code>-1</code> then the element
109     * can be from any namespace.
110     * <p>
111     * Lists of valid namespaces are created from choice content spec
112     * nodes that have any content spec nodes as children.
113     */
114    public static final short CONTENTSPECNODE_ANY = 6;
115
116    /**
117     * Represents any other namespace (XML Schema: ##other).
118     * <p>
119     * When the content spec node type is set to CONTENTSPECNODE_ANY_OTHER,
120     * <code>value</code> will contain the namespace that <em>cannot</em>
121     * occur.
122     */
123    public static final short CONTENTSPECNODE_ANY_OTHER = 7;
124
125    /** Represents any local element (XML Schema: ##local). */
126    public static final short CONTENTSPECNODE_ANY_LOCAL = 8;
127
128    /** prcessContent is 'lax' **/
129    public static final short CONTENTSPECNODE_ANY_LAX = 22;
130
131    public static final short CONTENTSPECNODE_ANY_OTHER_LAX = 23;
132
133    public static final short CONTENTSPECNODE_ANY_LOCAL_LAX = 24;
134
135    /** processContent is 'skip' **/
136
137    public static final short CONTENTSPECNODE_ANY_SKIP = 38;
138
139    public static final short CONTENTSPECNODE_ANY_OTHER_SKIP = 39;
140
141    public static final short CONTENTSPECNODE_ANY_LOCAL_SKIP = 40;
142    //
143    // Data
144    //
145
146    /**
147     * The content spec node type.
148     *
149     * @see #CONTENTSPECNODE_LEAF
150     * @see #CONTENTSPECNODE_ZERO_OR_ONE
151     * @see #CONTENTSPECNODE_ZERO_OR_MORE
152     * @see #CONTENTSPECNODE_ONE_OR_MORE
153     * @see #CONTENTSPECNODE_CHOICE
154     * @see #CONTENTSPECNODE_SEQ
155     */
156    public short type;
157
158    /**
159     * The "left hand" value object of the content spec node.
160     * leaf name.localpart, single child for unary ops, left child for binary ops.
161     */
162    public Object value;
163
164    /**
165     * The "right hand" value of the content spec node.
166     *  leaf name.uri, right child for binary ops
167     */
168    public Object otherValue;
169
170    //
171    // Constructors
172    //
173
174    /** Default constructor. */
175    public XMLContentSpec() {
176        clear();
177    }
178
179    /** Constructs a content spec with the specified values. */
180    public XMLContentSpec(short type, Object value, Object otherValue) {
181        setValues(type, value, otherValue);
182    }
183
184    /**
185     * Constructs a content spec from the values in the specified content spec.
186     */
187    public XMLContentSpec(XMLContentSpec contentSpec) {
188        setValues(contentSpec);
189    }
190
191    /**
192     * Constructs a content spec from the values specified by the given
193     * content spec provider and identifier.
194     */
195    public XMLContentSpec(XMLContentSpec.Provider provider,
196                          int contentSpecIndex) {
197        setValues(provider, contentSpecIndex);
198    }
199
200    //
201    // Public methods
202    //
203
204    /** Clears the values. */
205    public void clear() {
206        type = -1;
207        value = null;
208        otherValue = null;
209    }
210
211    /** Sets the values. */
212    public void setValues(short type, Object value, Object otherValue) {
213        this.type = type;
214        this.value = value;
215        this.otherValue = otherValue;
216    }
217
218    /** Sets the values of the specified content spec. */
219    public void setValues(XMLContentSpec contentSpec) {
220        type = contentSpec.type;
221        value = contentSpec.value;
222        otherValue = contentSpec.otherValue;
223    }
224
225    /**
226     * Sets the values from the values specified by the given content spec
227     * provider and identifier. If the specified content spec cannot be
228     * provided, the values of this content spec are cleared.
229     */
230    public void setValues(XMLContentSpec.Provider provider,
231                          int contentSpecIndex) {
232        if (!provider.getContentSpec(contentSpecIndex, this)) {
233            clear();
234        }
235    }
236
237
238    //
239    // Object methods
240    //
241
242    /** Returns a hash code for this node. */
243    public int hashCode() {
244        return type << 16 |
245               value.hashCode() << 8 |
246               otherValue.hashCode();
247    }
248
249    /** Returns true if the two objects are equal. */
250    public boolean equals(Object object) {
251        if (object != null && object instanceof XMLContentSpec) {
252            XMLContentSpec contentSpec = (XMLContentSpec)object;
253            return type == contentSpec.type &&
254                   value == contentSpec.value &&
255                   otherValue == contentSpec.otherValue;
256        }
257        return false;
258    }
259
260
261    //
262    // Interfaces
263    //
264
265    /**
266     * Provides a means for walking the structure built out of
267     * content spec "nodes". The user of this provider interface is
268     * responsible for knowing what the content spec node values
269     * "mean". If those values refer to content spec identifiers,
270     * then the user can call back into the provider to get the
271     * next content spec node in the structure.
272     *
273     * @xerces.internal
274     */
275    public interface Provider {
276
277        //
278        // XMLContentSpec.Provider methods
279        //
280
281        /**
282         * Fills in the provided content spec structure with content spec
283         * information for a unique identifier.
284         *
285         * @param contentSpecIndex The content spec identifier. All content
286         *                         spec "nodes" have a unique identifier.
287         * @param contentSpec      The content spec struct to fill in with
288         *                         the information.
289         *
290         * @return Returns true if the contentSpecIndex was found.
291         */
292        public boolean getContentSpec(int contentSpecIndex, XMLContentSpec contentSpec);
293
294    } // interface Provider
295
296} // class XMLContentSpec
297