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XMLContentSpec.javaAPI DocJava SE 5 API12358Fri Aug 26 14:55:46 BST 2005com.sun.org.apache.xerces.internal.impl.dtd

XMLContentSpec

public class XMLContentSpec extends Object
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.

version
$Id: XMLContentSpec.java,v 1.3 2002/01/29 01:15:10 lehors Exp $

Fields Summary
public static final short
CONTENTSPECNODE_LEAF
Name or #PCDATA. Leaf nodes that represent parsed character data (#PCDATA) have values of -1.
public static final short
CONTENTSPECNODE_ZERO_OR_ONE
Represents a zero or one occurence count, '?'.
public static final short
CONTENTSPECNODE_ZERO_OR_MORE
Represents a zero or more occurence count, '*'.
public static final short
CONTENTSPECNODE_ONE_OR_MORE
Represents a one or more occurence count, '+'.
public static final short
CONTENTSPECNODE_CHOICE
Represents choice, '|'.
public static final short
CONTENTSPECNODE_SEQ
Represents sequence, ','.
public static final short
CONTENTSPECNODE_ANY
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_OTHER
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_LOCAL
Represents any local element (XML Schema: ##local).
public static final short
CONTENTSPECNODE_ANY_LAX
prcessContent is 'lax'
public static final short
CONTENTSPECNODE_ANY_OTHER_LAX
public static final short
CONTENTSPECNODE_ANY_LOCAL_LAX
public static final short
CONTENTSPECNODE_ANY_SKIP
processContent is 'skip'
public static final short
CONTENTSPECNODE_ANY_OTHER_SKIP
public static final short
CONTENTSPECNODE_ANY_LOCAL_SKIP
public short
type
The content spec node type.
public Object
value
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
otherValue
The "right hand" value of the content spec node. leaf name.uri, right child for binary ops
Constructors Summary
public XMLContentSpec()
Default constructor.


    //
    // Constructors
    //

       
      
        clear();
    
public XMLContentSpec(short type, Object value, Object otherValue)
Constructs a content spec with the specified values.

        setValues(type, value, otherValue);
    
public XMLContentSpec(XMLContentSpec contentSpec)
Constructs a content spec from the values in the specified content spec.

        setValues(contentSpec);
    
public XMLContentSpec(Provider provider, int contentSpecIndex)
Constructs a content spec from the values specified by the given content spec provider and identifier.

        setValues(provider, contentSpecIndex);
    
Methods Summary
public voidclear()
Clears the values.

        type = -1;
        value = null;
        otherValue = null;
    
public booleanequals(java.lang.Object object)
Returns true if the two objects are equal.

        if (object != null && object instanceof XMLContentSpec) {
            XMLContentSpec contentSpec = (XMLContentSpec)object;
            return type == contentSpec.type &&
                   value == contentSpec.value &&
                   otherValue == contentSpec.otherValue;
        }
        return false;
    
public inthashCode()
Returns a hash code for this node.

        return type << 16 | 
               value.hashCode() << 8 |
               otherValue.hashCode();
    
public voidsetValues(short type, java.lang.Object value, java.lang.Object otherValue)
Sets the values.

        this.type = type;
        this.value = value;
        this.otherValue = otherValue;
    
public voidsetValues(com.sun.org.apache.xerces.internal.impl.dtd.XMLContentSpec contentSpec)
Sets the values of the specified content spec.

        type = contentSpec.type;
        value = contentSpec.value;
        otherValue = contentSpec.otherValue;
    
public voidsetValues(com.sun.org.apache.xerces.internal.impl.dtd.XMLContentSpec$Provider provider, int contentSpecIndex)
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.

        if (!provider.getContentSpec(contentSpecIndex, this)) {
            clear();
        }