org.openanzo.glitter.syntax.abstrakt
Class Expression

java.lang.Object
  org.openanzo.glitter.syntax.abstrakt.Expression

Direct Known Subclasses:

FunctionCall, SimpleExpression

public abstract class Expression
extends java.lang.Object

Expression is an abstract base class for expressions within a FILTER or ORDER BY clause. Expressions can be evaluated against a set of bindings to produce a result.

Author:

lee

Constructor Summary

Expression()

Method Summary

abstract RDFTerm	evaluate(PatternSolution environment)
abstract java.util.Set<Variable>	getReferencedVariables()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Expression

public Expression()

Method Detail

evaluate

public abstract RDFTerm evaluate(PatternSolution environment)
                          throws ExpressionEvaluationException

Parameters:

environment - A set of bindings to use to evaluate Bindable objects in the expression.

Returns:

The RDFTerm that is the value of evaluating this expression.

Throws:

ExpressionEvaluationException - If there is an error (e.g. a type error) in evaluating this expression.

getReferencedVariables

public abstract java.util.Set<Variable> getReferencedVariables()

Returns:

A set of all the variables that occur in this expression.