org.apache.xerces.impl.dtd.XMLContentSpec Maven / Gradle / Ivy
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.xerces.impl.dtd;
/**
* ContentSpec really exists to aid the parser classes in implementing
* access to the grammar.
*
* This class is used by the DTD scanner and the validator classes,
* allowing them to be used separately or together. This "struct"
* class is used to build content models for validation, where it
* is more efficient to fetch all of the information for each of
* these content model "fragments" than to fetch each field one at
* a time. Since configurations are allowed to have validators
* without a DTD scanner (i.e. a schema validator) and a DTD scanner
* without a validator (non-validating processor), this class can be
* used by each without requiring the presence of the other.
*
* When processing element declarations, the DTD scanner will build
* up a representation of the content model using the node types that
* are defined here. Since a non-validating processor only needs to
* remember the type of content model declared (i.e. ANY, EMPTY, MIXED,
* or CHILDREN), it is free to discard the specific details of the
* MIXED and CHILDREN content models described using this class.
*
* In the typical case of a validating processor reading the grammar
* of the document from a DTD, the information about the content model
* declared will be preserved and later "compiled" into an efficient
* form for use during element validation. Each content spec node
* that is saved is assigned a unique index that is used as a handle
* for the "value" or "otherValue" fields of other content spec nodes.
* A leaf node has a "value" that is either an index in the string
* pool of the element type of that leaf, or a value of -1 to indicate
* the special "#PCDATA" leaf type used in a mixed content model.
*
* For a mixed content model, the content spec will be made up of
* leaf and choice content spec nodes, with an optional "zero or more"
* node. For example, the mixed content declaration "(#PCDATA)" would
* contain a single leaf node with a node value of -1. A mixed content
* declaration of "(#PCDATA|foo)*" would have a content spec consisting
* of two leaf nodes, for the "#PCDATA" and "foo" choices, a choice node
* with the "value" set to the index of the "#PCDATA" leaf node and the
* "otherValue" set to the index of the "foo" leaf node, and a "zero or
* more" node with the "value" set to the index of the choice node. If
* the content model has more choices, for example "(#PCDATA|a|b)*", then
* there will be more corresponding choice and leaf nodes, the choice
* nodes will be chained together through the "value" field with each
* leaf node referenced by the "otherValue" field.
*
* For element content models, there are sequence nodes and also "zero or
* one" and "one or more" nodes. The leaf nodes would always have a valid
* string pool index, as the "#PCDATA" leaf is not used in the declarations
* for element content models.
*
* @xerces.internal
*
* @version $Id: XMLContentSpec.java 446755 2006-09-15 21:56:27Z mrglavas $
*/
public class XMLContentSpec {
//
// Constants
//
/**
* Name or #PCDATA. Leaf nodes that represent parsed character
* data (#PCDATA) have values of -1.
*/
public static final short CONTENTSPECNODE_LEAF = 0;
/** Represents a zero or one occurence count, '?'. */
public static final short CONTENTSPECNODE_ZERO_OR_ONE = 1;
/** Represents a zero or more occurence count, '*'. */
public static final short CONTENTSPECNODE_ZERO_OR_MORE = 2;
/** Represents a one or more occurence count, '+'. */
public static final short CONTENTSPECNODE_ONE_OR_MORE = 3;
/** Represents choice, '|'. */
public static final short CONTENTSPECNODE_CHOICE = 4;
/** Represents sequence, ','. */
public static final short CONTENTSPECNODE_SEQ = 5;
/**
* Represents any namespace specified namespace. When the element
* found in the document must belong to a specific namespace,
* otherValue will contain the name of the namespace.
* If otherValue is -1 then the element
* can be from any namespace.
*
* Lists of valid namespaces are created from choice content spec
* nodes that have any content spec nodes as children.
*/
public static final short CONTENTSPECNODE_ANY = 6;
/**
* Represents any other namespace (XML Schema: ##other).
*
* When the content spec node type is set to CONTENTSPECNODE_ANY_OTHER,
* value will contain the namespace that cannot
* occur.
*/
public static final short CONTENTSPECNODE_ANY_OTHER = 7;
/** Represents any local element (XML Schema: ##local). */
public static final short CONTENTSPECNODE_ANY_LOCAL = 8;
/** prcessContent is 'lax' **/
public static final short CONTENTSPECNODE_ANY_LAX = 22;
public static final short CONTENTSPECNODE_ANY_OTHER_LAX = 23;
public static final short CONTENTSPECNODE_ANY_LOCAL_LAX = 24;
/** processContent is 'skip' **/
public static final short CONTENTSPECNODE_ANY_SKIP = 38;
public static final short CONTENTSPECNODE_ANY_OTHER_SKIP = 39;
public static final short CONTENTSPECNODE_ANY_LOCAL_SKIP = 40;
//
// Data
//
/**
* The content spec node type.
*
* @see #CONTENTSPECNODE_LEAF
* @see #CONTENTSPECNODE_ZERO_OR_ONE
* @see #CONTENTSPECNODE_ZERO_OR_MORE
* @see #CONTENTSPECNODE_ONE_OR_MORE
* @see #CONTENTSPECNODE_CHOICE
* @see #CONTENTSPECNODE_SEQ
*/
public short type;
/**
* The "left hand" value object of the content spec node.
* leaf name.localpart, single child for unary ops, left child for binary ops.
*/
public Object value;
/**
* The "right hand" value of the content spec node.
* leaf name.uri, right child for binary ops
*/
public Object otherValue;
//
// Constructors
//
/** Default constructor. */
public XMLContentSpec() {
clear();
}
/** Constructs a content spec with the specified values. */
public XMLContentSpec(short type, Object value, Object otherValue) {
setValues(type, value, otherValue);
}
/**
* Constructs a content spec from the values in the specified content spec.
*/
public XMLContentSpec(XMLContentSpec contentSpec) {
setValues(contentSpec);
}
/**
* Constructs a content spec from the values specified by the given
* content spec provider and identifier.
*/
public XMLContentSpec(XMLContentSpec.Provider provider,
int contentSpecIndex) {
setValues(provider, contentSpecIndex);
}
//
// Public methods
//
/** Clears the values. */
public void clear() {
type = -1;
value = null;
otherValue = null;
}
/** Sets the values. */
public void setValues(short type, Object value, Object otherValue) {
this.type = type;
this.value = value;
this.otherValue = otherValue;
}
/** Sets the values of the specified content spec. */
public void setValues(XMLContentSpec contentSpec) {
type = contentSpec.type;
value = contentSpec.value;
otherValue = contentSpec.otherValue;
}
/**
* Sets the values from the values specified by the given content spec
* provider and identifier. If the specified content spec cannot be
* provided, the values of this content spec are cleared.
*/
public void setValues(XMLContentSpec.Provider provider,
int contentSpecIndex) {
if (!provider.getContentSpec(contentSpecIndex, this)) {
clear();
}
}
//
// Object methods
//
/** Returns a hash code for this node. */
public int hashCode() {
return type << 16 |
value.hashCode() << 8 |
otherValue.hashCode();
}
/** Returns true if the two objects are equal. */
public boolean equals(Object object) {
if (object != null && object instanceof XMLContentSpec) {
XMLContentSpec contentSpec = (XMLContentSpec)object;
return type == contentSpec.type &&
value == contentSpec.value &&
otherValue == contentSpec.otherValue;
}
return false;
}
//
// Interfaces
//
/**
* Provides a means for walking the structure built out of
* content spec "nodes". The user of this provider interface is
* responsible for knowing what the content spec node values
* "mean". If those values refer to content spec identifiers,
* then the user can call back into the provider to get the
* next content spec node in the structure.
*
* @xerces.internal
*/
public interface Provider {
//
// XMLContentSpec.Provider methods
//
/**
* Fills in the provided content spec structure with content spec
* information for a unique identifier.
*
* @param contentSpecIndex The content spec identifier. All content
* spec "nodes" have a unique identifier.
* @param contentSpec The content spec struct to fill in with
* the information.
*
* @return Returns true if the contentSpecIndex was found.
*/
public boolean getContentSpec(int contentSpecIndex, XMLContentSpec contentSpec);
} // interface Provider
} // class XMLContentSpec