java.lang.Object | |
↳ | org.apache.xerces.impl.dtd.XMLContentSpec |
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
Nested Classes | |||||||||||
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XMLContentSpec.Provider | Provides a means for walking the structure built out of content spec "nodes". |
Constants | |||||||||||
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short | CONTENTSPECNODE_ANY | Represents any namespace specified namespace. | |||||||||
short | CONTENTSPECNODE_ANY_LAX | prcessContent is 'lax' | |||||||||
short | CONTENTSPECNODE_ANY_LOCAL | Represents any local element (XML Schema: ##local). | |||||||||
short | CONTENTSPECNODE_ANY_LOCAL_LAX | ||||||||||
short | CONTENTSPECNODE_ANY_LOCAL_SKIP | ||||||||||
short | CONTENTSPECNODE_ANY_OTHER | Represents any other namespace (XML Schema: ##other). | |||||||||
short | CONTENTSPECNODE_ANY_OTHER_LAX | ||||||||||
short | CONTENTSPECNODE_ANY_OTHER_SKIP | ||||||||||
short | CONTENTSPECNODE_ANY_SKIP | processContent is 'skip' | |||||||||
short | CONTENTSPECNODE_CHOICE | Represents choice, '|'. | |||||||||
short | CONTENTSPECNODE_LEAF | Name or #PCDATA. | |||||||||
short | CONTENTSPECNODE_ONE_OR_MORE | Represents a one or more occurence count, '+'. | |||||||||
short | CONTENTSPECNODE_SEQ | Represents sequence, ','. | |||||||||
short | CONTENTSPECNODE_ZERO_OR_MORE | Represents a zero or more occurence count, '*'. | |||||||||
short | CONTENTSPECNODE_ZERO_OR_ONE | Represents a zero or one occurence count, '?'. |
Fields | |||||||||||
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otherValue | The "right hand" value of the content spec node. | ||||||||||
type | The content spec node type. | ||||||||||
value | The "left hand" value object of the content spec node. |
Public Constructors | |||||||||||
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Default constructor.
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Constructs a content spec with the specified values.
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Constructs a content spec from the values in the specified content spec.
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Constructs a content spec from the values specified by the given
content spec provider and identifier.
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Public Methods | |||||||||||
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Clears the values.
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Returns true if the two objects are equal.
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Returns a hash code for this node.
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Sets the values from the values specified by the given content spec
provider and identifier.
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Sets the values.
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Sets the values of the specified content spec.
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Inherited Methods | |||||||||||
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From class
java.lang.Object
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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.
prcessContent is 'lax'
Represents any local element (XML Schema: ##local).
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.
processContent is 'skip'
Represents choice, '|'.
Name or #PCDATA. Leaf nodes that represent parsed character data (#PCDATA) have values of -1.
Represents a one or more occurence count, '+'.
Represents sequence, ','.
Represents a zero or more occurence count, '*'.
Represents a zero or one occurence count, '?'.
The "right hand" value of the content spec node. leaf name.uri, right child for binary ops
The content spec node type.
The "left hand" value object of the content spec node. leaf name.localpart, single child for unary ops, left child for binary ops.
Default constructor.
Constructs a content spec with the specified values.
Constructs a content spec from the values in the specified content spec.
Constructs a content spec from the values specified by the given content spec provider and identifier.
Clears the values.
Returns a hash code for this node.
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.