com.bigdata.rdf.sparql.ast

Class VarNode

java.lang.Object

com.bigdata.bop.CoreBaseBOp

com.bigdata.bop.ModifiableBOpBase

com.bigdata.rdf.sparql.ast.ASTBase

com.bigdata.rdf.sparql.ast.ValueExpressionNode

com.bigdata.rdf.sparql.ast.TermNode

com.bigdata.rdf.sparql.ast.VarNode

All Implemented Interfaces:

BOp, IValueExpressionNode, IPropertySet, Serializable, Cloneable

public class VarNode
extends TermNode

Used to represent a variable in the AST.

Note: Unlike Var, this class does NOT support reference testing for equality. Multiple VarNode instances MAY exist for the same IVariable. You must either compare the value returned by #getVar() (which is canonical) or use CoreBaseBOp.equals(Object).

Author:

mikepersonick

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	VarNode.Annotations

Field Summary

Fields inherited from class com.bigdata.bop.CoreBaseBOp

DEFAULT_INITIAL_CAPACITY

Fields inherited from interface com.bigdata.bop.BOp

NOANNS, NOARGS

Constructor Summary

Constructors

Constructor and Description
VarNode(BOp[] args, Map<String,Object> anns) Required shallow copy constructor.
VarNode(IVariable<IV> var)
VarNode(String var)
VarNode(VarNode op) Constructor required for com.bigdata.bop.BOpUtility#deepCopy(FilterNode).

Method Summary

Methods

Modifier and Type	Method and Description
static VarNode	freshVarNode()
IVariable<IV>	getValueExpression() Strengthen return type.
boolean	isAnonymous() Return true if this is an anonymous variable (anonymous variables are introduced during a rewrite of the query in which blank nodes are replaced by anonymous variables).
boolean	isSolutionSet() Return true if the variable represents a solution set name.
boolean	isWildcard() Return true iff the variable is *.
void	setAnonymous(boolean anonymous) Mark this as an anonymous variable (one introduced during a query rewrite in place of a blank node).
void	setSolutionSet(boolean solutionSet) Mark this as a variable which actually conveys the name of a solution set.
void	setValueExpression(IValueExpression<? extends IV> ve) Hot-swap the IVariable underneath this VarNode.
String	toString() Overridden to mark metadata about variables.

Methods inherited from class com.bigdata.rdf.sparql.ast.TermNode

getValue, invalidate, toString

Methods inherited from class com.bigdata.rdf.sparql.ast.ValueExpressionNode

getRequiredValueExpression, isConstant, isFunction, isVariable, toShortString

Methods inherited from class com.bigdata.rdf.sparql.ast.ASTBase

addExplainHint, getExplainHints, getQueryHint, getQueryHint, getQueryHintAsBoolean, getQueryHintAsBoolean, getQueryHintAsInteger, getQueryHints, replaceAllWith, setQueryHint, setQueryHints

Methods inherited from class com.bigdata.bop.ModifiableBOpBase

addArg, addArg, addArgIfAbsent, annotations, annotationsEqual, argIterator, args, arity, clearProperty, copyAll, get, getProperty, indexOf, removeArg, replaceWith, setArg, setArgs, setId, setProperty, setUnboundProperty, toArray, toArray

Methods inherited from class com.bigdata.bop.CoreBaseBOp

annotationsEqual, annotationsToString, annotationsToString, annotationValueToString, checkArgs, clone, equals, getEvaluationContext, getId, getProperty, getRequiredProperty, hashCode, indent, isController, mutation, shortenName

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

VarNode

public VarNode(VarNode op)

Constructor required for com.bigdata.bop.BOpUtility#deepCopy(FilterNode).

VarNode

public VarNode(BOp[] args,
       Map<String,Object> anns)

Required shallow copy constructor.

VarNode

public VarNode(String var)

VarNode

public VarNode(IVariable<IV> var)

Method Detail

isAnonymous

public boolean isAnonymous()

Return true if this is an anonymous variable (anonymous variables are introduced during a rewrite of the query in which blank nodes are replaced by anonymous variables). This marker is useful mainly when reading the AST tree as an aid to understanding where a given variable came from in the original query.

setAnonymous

public void setAnonymous(boolean anonymous)

Mark this as an anonymous variable (one introduced during a query rewrite in place of a blank node).

Parameters:

anonymous -

isSolutionSet

public boolean isSolutionSet()

Return true if the variable represents a solution set name.

setSolutionSet

public void setSolutionSet(boolean solutionSet)

Mark this as a variable which actually conveys the name of a solution set.

Parameters:

true - if the variable represents a solution set name.

isWildcard

public boolean isWildcard()

Return true iff the variable is *.

getValueExpression

public IVariable<IV> getValueExpression()

Strengthen return type.

Specified by:

getValueExpression in interface IValueExpressionNode

Overrides:

getValueExpression in class TermNode

setValueExpression

public void setValueExpression(IValueExpression<? extends IV> ve)

Hot-swap the IVariable underneath this VarNode.

Specified by:

setValueExpression in interface IValueExpressionNode

Overrides:

setValueExpression in class TermNode

toString

public String toString()

Overridden to mark metadata about variables.

Specified by:

toString in interface BOp

Overrides:

toString in class CoreBaseBOp

freshVarNode

public static VarNode freshVarNode()

Returns:

a varnode containing a fresh (uniquely distinct) variable