Package org.apache.jena.sparql.expr

Class ExprVar

java.lang.Object

org.apache.jena.sparql.expr.ExprNode

org.apache.jena.sparql.expr.ExprVar

All Implemented Interfaces:

Expr

public class ExprVar
extends ExprNode

An expression that is a variable in an expression.

Field Summary

Fields inherited from interface org.apache.jena.sparql.expr.Expr

CMP_EQUAL, CMP_GREATER, CMP_INDETERMINATE, CMP_LESS, CMP_UNEQUAL, NONE

Constructor Summary

Constructors

Constructor	Description
ExprVar(java.lang.String name)
ExprVar(Node n)
ExprVar(Var v)

Method Summary

Modifier and Type	Method	Description
Expr	apply(ExprTransform transform)
Expr	applyNodeTransform(NodeTransform transform)	Rewrite, applying a node->node transformation
java.lang.String	asSparqlExpr()
Var	asVar()	Convert to a Var variable.
Expr	copy(Var v)
Expr	copySubstitute(Binding binding)	Deep copy with substitution
boolean	equals(Expr other, boolean bySyntax)	General equality operation - consider this to be 'protected'
NodeValue	eval(Binding binding, FunctionEnv env)	Evaluate this expression against the binding
void	format(Query query, org.apache.jena.atlas.io.IndentedWriter out)
Node	getAsNode()
ExprVar	getExprVar()	Variable (or null)
java.lang.String	getVarName()	Variable name (returns null if not a variable)
int	hashCode()	Expr are used in both syntax and algebra.
boolean	isVariable()	Answer whether this is a variable.
java.lang.String	toPrefixString()
java.lang.String	toString()
void	visit(ExprVisitor visitor)

Methods inherited from class org.apache.jena.sparql.expr.ExprNode

deepCopy, equals, equalsBySyntax, getConstant, getExpr, getFunction, getGraphPattern, getVarsMentioned, isConstant, isExpr, isFunction, isGraphPattern, isSatisfied

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ExprVar

public ExprVar(java.lang.String name)

ExprVar

public ExprVar(Node n)

ExprVar

public ExprVar(Var v)

Method Detail

eval

public NodeValue eval(Binding binding,
                      FunctionEnv env)

Description copied from interface: Expr

Evaluate this expression against the binding

Specified by:

eval in interface Expr

Specified by:

eval in class ExprNode

copySubstitute

public Expr copySubstitute(Binding binding)

Description copied from interface: Expr

Deep copy with substitution

Specified by:

copySubstitute in interface Expr

Specified by:

copySubstitute in class ExprNode

applyNodeTransform

public Expr applyNodeTransform(NodeTransform transform)

Description copied from interface: Expr

Rewrite, applying a node->node transformation

Specified by:

applyNodeTransform in interface Expr

Specified by:

applyNodeTransform in class ExprNode

copy

public Expr copy(Var v)

visit

public void visit(ExprVisitor visitor)

apply

public Expr apply(ExprTransform transform)

format

public void format(Query query,
                   org.apache.jena.atlas.io.IndentedWriter out)

hashCode

public int hashCode()

Description copied from interface: Expr

Expr are used in both syntax and algebra. There is no syntax to algebra translation step because the parser uses operator precedence to build the right evaluation structure directly.

The exceptions to this are the NOT EXISTS and EXISTS expressions which involve a query pattern. As a result there are different ways in syntax to produce the same algebra form.

Two Expr are considered equal if they are equal as algebra expressions. hashCode and equals must implement that.

There is also equalsBySyntax. Because two different syntax forms can yield the same algebra, but two different algebra forms must be different syntax, equalsBySyntax implies equals (by alegbra).

Hence, different hashCode => not equalsBySyntax.

Specified by:

hashCode in interface Expr

Specified by:

hashCode in class ExprNode

equals

public boolean equals(Expr other,
                      boolean bySyntax)

Description copied from interface: Expr

General equality operation - consider this to be 'protected'

Specified by:

equals in interface Expr

Specified by:

equals in class ExprNode

isVariable

public boolean isVariable()

Description copied from interface: Expr

Answer whether this is a variable.

Specified by:

isVariable in interface Expr

Overrides:

isVariable in class ExprNode

getVarName

public java.lang.String getVarName()

Description copied from interface: Expr

Variable name (returns null if not a variable)

Specified by:

getVarName in interface Expr

Overrides:

getVarName in class ExprNode

Returns:

Returns the name.

getExprVar

public ExprVar getExprVar()

Description copied from interface: Expr

Variable (or null)

Specified by:

getExprVar in interface Expr

Overrides:

getExprVar in class ExprNode

asVar

public Var asVar()

Description copied from interface: Expr

Convert to a Var variable.

Specified by:

asVar in interface Expr

Overrides:

asVar in class ExprNode

getAsNode

public Node getAsNode()

toPrefixString

public java.lang.String toPrefixString()

asSparqlExpr

public java.lang.String asSparqlExpr()

toString

public java.lang.String toString()

Overrides:

toString in class ExprNode