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.

INTERNAL:

Usage of this class is not supported. It may be altered or removed at any time.
Version:
$Id: XMLContentSpec.java 446755 2006-09-15 21:56:27Z mrglavas $
  • Field Details

    • 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:
    • CONTENTSPECNODE_ZERO_OR_ONE

      public static final short CONTENTSPECNODE_ZERO_OR_ONE
      Represents a zero or one occurence count, '?'.
      See Also:
    • CONTENTSPECNODE_ZERO_OR_MORE

      public static final short CONTENTSPECNODE_ZERO_OR_MORE
      Represents a zero or more occurence count, '*'.
      See Also:
    • CONTENTSPECNODE_ONE_OR_MORE

      public static final short CONTENTSPECNODE_ONE_OR_MORE
      Represents a one or more occurence count, '+'.
      See Also:
    • CONTENTSPECNODE_CHOICE

      public static final short CONTENTSPECNODE_CHOICE
      Represents choice, '|'.
      See Also:
    • CONTENTSPECNODE_SEQ

      public static final short CONTENTSPECNODE_SEQ
      Represents sequence, ','.
      See Also:
    • 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:
    • 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.

      See Also:
    • CONTENTSPECNODE_ANY_LOCAL

      public static final short CONTENTSPECNODE_ANY_LOCAL
      Represents any local element (XML Schema: ##local).
      See Also:
    • CONTENTSPECNODE_ANY_LAX

      public static final short CONTENTSPECNODE_ANY_LAX
      prcessContent is 'lax'
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    • CONTENTSPECNODE_ANY_OTHER_LAX

      public static final short CONTENTSPECNODE_ANY_OTHER_LAX
      See Also:
    • CONTENTSPECNODE_ANY_LOCAL_LAX

      public static final short CONTENTSPECNODE_ANY_LOCAL_LAX
      See Also:
    • CONTENTSPECNODE_ANY_SKIP

      public static final short CONTENTSPECNODE_ANY_SKIP
      processContent is 'skip'
      See Also:
    • CONTENTSPECNODE_ANY_OTHER_SKIP

      public static final short CONTENTSPECNODE_ANY_OTHER_SKIP
      See Also:
    • CONTENTSPECNODE_ANY_LOCAL_SKIP

      public static final short CONTENTSPECNODE_ANY_LOCAL_SKIP
      See Also:
    • type

      public short type
      The content spec node type.
      See Also:
    • 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 Details

    • 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 Details

    • 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