org.apache.xerces.impl.dtd

Class XMLContentSpec

java.lang.Object

org.apache.xerces.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:

$Id$

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	XMLContentSpec.Provider Provides a means for walking the structure built out of content spec "nodes".

Field Summary

Fields

Modifier and Type	Field and Description
static short	CONTENTSPECNODE_ANY Represents any namespace specified namespace.
static short	CONTENTSPECNODE_ANY_LAX prcessContent is 'lax'
static short	CONTENTSPECNODE_ANY_LOCAL Represents any local element (XML Schema: ##local).
static short	CONTENTSPECNODE_ANY_LOCAL_LAX
static short	CONTENTSPECNODE_ANY_LOCAL_SKIP
static short	CONTENTSPECNODE_ANY_OTHER Represents any other namespace (XML Schema: ##other).
static short	CONTENTSPECNODE_ANY_OTHER_LAX
static short	CONTENTSPECNODE_ANY_OTHER_SKIP
static short	CONTENTSPECNODE_ANY_SKIP processContent is 'skip'
static short	CONTENTSPECNODE_CHOICE Represents choice, '|'.
static short	CONTENTSPECNODE_LEAF Name or #PCDATA.
static short	CONTENTSPECNODE_ONE_OR_MORE Represents a one or more occurence count, '+'.
static short	CONTENTSPECNODE_SEQ Represents sequence, ','.
static short	CONTENTSPECNODE_ZERO_OR_MORE Represents a zero or more occurence count, '*'.
static short	CONTENTSPECNODE_ZERO_OR_ONE Represents a zero or one occurence count, '?'.
Object	otherValue The "right hand" value of the content spec node.
short	type The content spec node type.
Object	value The "left hand" value object of the content spec node.

Constructor Summary

Constructors

Constructor and Description
XMLContentSpec() Default constructor.
XMLContentSpec(short type, Object value, Object otherValue) Constructs a content spec with the specified values.
XMLContentSpec(XMLContentSpec.Provider provider, int contentSpecIndex) Constructs a content spec from the values specified by the given content spec provider and identifier.
XMLContentSpec(XMLContentSpec contentSpec) Constructs a content spec from the values in the specified content spec.

Method Summary

Methods

Modifier and Type	Method and Description
void	clear() Clears the values.
boolean	equals(Object object) Returns true if the two objects are equal.
int	hashCode() Returns a hash code for this node.
void	setValues(short type, Object value, Object otherValue) Sets the values.
void	setValues(XMLContentSpec.Provider provider, int contentSpecIndex) Sets the values from the values specified by the given content spec provider and identifier.
void	setValues(XMLContentSpec contentSpec) Sets the values of the specified content spec.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Field Detail

CONTENTSPECNODE_LEAF

public static final short CONTENTSPECNODE_LEAF

Name or #PCDATA. Leaf nodes that represent parsed character data (#PCDATA) have values of -1.

See Also:

Constant Field Values

CONTENTSPECNODE_ZERO_OR_ONE

public static final short CONTENTSPECNODE_ZERO_OR_ONE

Represents a zero or one occurence count, '?'.

See Also:

Constant Field Values

CONTENTSPECNODE_ZERO_OR_MORE

public static final short CONTENTSPECNODE_ZERO_OR_MORE

Represents a zero or more occurence count, '*'.

See Also:

Constant Field Values

CONTENTSPECNODE_ONE_OR_MORE

public static final short CONTENTSPECNODE_ONE_OR_MORE

Represents a one or more occurence count, '+'.

See Also:

Constant Field Values

CONTENTSPECNODE_CHOICE

public static final short CONTENTSPECNODE_CHOICE

Represents choice, '|'.

See Also:

Constant Field Values

CONTENTSPECNODE_SEQ

public static final short CONTENTSPECNODE_SEQ

Represents sequence, ','.

See Also:

Constant Field Values

CONTENTSPECNODE_ANY

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.

See Also:

Constant Field Values

CONTENTSPECNODE_ANY_OTHER

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.

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Constant Field Values

CONTENTSPECNODE_ANY_LOCAL

public static final short CONTENTSPECNODE_ANY_LOCAL

Represents any local element (XML Schema: ##local).

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Constant Field Values

CONTENTSPECNODE_ANY_LAX

public static final short CONTENTSPECNODE_ANY_LAX

prcessContent is 'lax'

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Constant Field Values

CONTENTSPECNODE_ANY_OTHER_LAX

public static final short CONTENTSPECNODE_ANY_OTHER_LAX

See Also:

Constant Field Values

CONTENTSPECNODE_ANY_LOCAL_LAX

public static final short CONTENTSPECNODE_ANY_LOCAL_LAX

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Constant Field Values

CONTENTSPECNODE_ANY_SKIP

public static final short CONTENTSPECNODE_ANY_SKIP

processContent is 'skip'

See Also:

Constant Field Values

CONTENTSPECNODE_ANY_OTHER_SKIP

public static final short CONTENTSPECNODE_ANY_OTHER_SKIP

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Constant Field Values

CONTENTSPECNODE_ANY_LOCAL_SKIP

public static final short CONTENTSPECNODE_ANY_LOCAL_SKIP

See Also:

Constant Field Values

type

public short type

The content spec node type.

See Also:

CONTENTSPECNODE_LEAF, CONTENTSPECNODE_ZERO_OR_ONE, CONTENTSPECNODE_ZERO_OR_MORE, CONTENTSPECNODE_ONE_OR_MORE, CONTENTSPECNODE_CHOICE, CONTENTSPECNODE_SEQ

value

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.

otherValue

public Object otherValue

The "right hand" value of the content spec node. leaf name.uri, right child for binary ops

Constructor Detail

XMLContentSpec

public XMLContentSpec()

Default constructor.

XMLContentSpec

public XMLContentSpec(short type,
              Object value,
              Object otherValue)

Constructs a content spec with the specified values.

XMLContentSpec

public XMLContentSpec(XMLContentSpec contentSpec)

Constructs a content spec from the values in the specified content spec.

XMLContentSpec

public XMLContentSpec(XMLContentSpec.Provider provider,
              int contentSpecIndex)

Constructs a content spec from the values specified by the given content spec provider and identifier.

Method Detail

clear

public void clear()

Clears the values.

setValues

public void setValues(short type,
             Object value,
             Object otherValue)

Sets the values.

setValues

public void setValues(XMLContentSpec contentSpec)

Sets the values of the specified content spec.

setValues

public void setValues(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.

hashCode

public int hashCode()

Returns a hash code for this node.

Overrides:

hashCode in class Object

equals

public boolean equals(Object object)

Returns true if the two objects are equal.

Overrides:

equals in class Object