com.hp.hpl.jena.reasoner.rulesys
Class Node_RuleVariable

java.lang.Object
  com.hp.hpl.jena.graph.Node
      com.hp.hpl.jena.graph.Node_Fluid
          com.hp.hpl.jena.graph.Node_Variable
              com.hp.hpl.jena.reasoner.rulesys.Node_RuleVariable

public class Node_RuleVariable
extends Node_Variable

A variation on the normal Node_Variable which support for value bindings. Currently the forward rule system stores the values externally but requires variables to have an offset index in the rule environment vector. The variables can also suport prolog-like reference chains and trails but these are not yet used.

Note that this should not be used in a real Triple, in particular it should not end up in a Graph. It is only needed for the rule systems.

Version:

$Revision: 1.3 $ on $Date: 2009-08-05 14:43:24 $

Author:

Dave Reynolds

Nested Class Summary

Nested classes/interfaces inherited from class com.hp.hpl.jena.graph.Node_Variable

Node_Variable.VariableName

Nested classes/interfaces inherited from class com.hp.hpl.jena.graph.Node

Node.NotLiteral

Field Summary

static Node_RuleVariable

WILD A static wildcard - like Node.ANY but tests equl to other Node_RuleVariables

Fields inherited from class com.hp.hpl.jena.graph.Node

ANY, NULL

Constructor Summary

Node_RuleVariable(String label, int index)
Constructor

Method Summary

Node_RuleVariable	cloneNode() Clone the rule variable to allow multiple rule instaces to be active at the same time.
Node	deref() Dereference a variable by following the reference chain.
boolean	equals(Object o) Nodes only equal other Nodes that have equal labels.
int	getIndex() Returns the variable's index in a binding vector.
Node	getRawBoundValue() Return the raw value to which this variable is bound (via LP binding) with no dereferencing.
int	hashCode()
boolean	isUnbound() Test if the variable is unbound (in the brule sense).
static boolean	sameNodeAs(Node n, Node m) Compare two nodes, taking into account variable indices.
boolean	sameValueAs(Object o) Test that two nodes are semantically equivalent.
void	setIndex(int index) Changes the variable's index.
void	simpleBind(Node node) Binds a value to the brule version of the variable.
String	toString() printable form
void	unbind() Set the variable to be unbound (in the brule sense)

Methods inherited from class com.hp.hpl.jena.graph.Node_Variable

getName, isVariable, variable, visitWith

Methods inherited from class com.hp.hpl.jena.graph.Node_Fluid

isConcrete

Methods inherited from class com.hp.hpl.jena.graph.Node

cache, create, createAnon, createAnon, createLiteral, createLiteral, createLiteral, createLiteral, createLiteral, createUncachedLiteral, createUncachedLiteral, createURI, createVariable, getBlankNodeId, getBlankNodeLabel, getIndexingValue, getLiteral, getLiteralDatatype, getLiteralDatatypeURI, getLiteralIsXML, getLiteralLanguage, getLiteralLexicalForm, getLiteralValue, getLocalName, getNameSpace, getType, getURI, hasURI, isBlank, isLiteral, isURI, matches, toString, toString, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Detail

WILD

public static final Node_RuleVariable WILD

A static wildcard - like Node.ANY but tests equl to other Node_RuleVariables

Constructor Detail

Node_RuleVariable

public Node_RuleVariable(String label,
                         int index)

Constructor

Parameters:

label - the text label for the variable

index - the calculated index of this variable in the rule

Method Detail

getIndex

public int getIndex()

Returns the variable's index in a binding vector.

Returns:

int

setIndex

public void setIndex(int index)

Changes the variable's index. This is used in LP rules which classify the variables into different sequences.

simpleBind

public void simpleBind(Node node)

Binds a value to the brule version of the variable. Does not follow any reference trail, assues we have already been derefenced.

Parameters:

node - a concrete Node value or another Node_RuleVariable to alias to

deref

public Node deref()

Dereference a variable by following the reference chain.

Returns:

either a concrete node value or the last variable in the reference chain.

getRawBoundValue

public Node getRawBoundValue()

Return the raw value to which this variable is bound (via LP binding) with no dereferencing.

unbind

public void unbind()

Set the variable to be unbound (in the brule sense)

isUnbound

public boolean isUnbound()

Test if the variable is unbound (in the brule sense).

cloneNode

public Node_RuleVariable cloneNode()

Clone the rule variable to allow multiple rule instaces to be active at the same time.

toString

public String toString()

printable form

Overrides:

toString in class Node_Variable

equals

public boolean equals(Object o)

Description copied from class: Node

Nodes only equal other Nodes that have equal labels.

Overrides:

equals in class Node_Variable

hashCode

public int hashCode()

Overrides:

hashCode in class Node

sameValueAs

public boolean sameValueAs(Object o)

Test that two nodes are semantically equivalent.

Overrides:

sameValueAs in class Node

sameNodeAs

public static boolean sameNodeAs(Node n,
                                 Node m)

Compare two nodes, taking into account variable indices.