Package com.tonic.analysis.query.eval

Class ConditionEvaluator

java.lang.Object

com.tonic.analysis.query.eval.ConditionEvaluator

All Implemented Interfaces:

Condition.Visitor<Boolean>

public final class ConditionEvaluator
extends Object
implements Condition.Visitor<Boolean>

Interprets a Condition against a Subject.

Constructor Summary

Constructors

Constructor	Description
ConditionEvaluator(AttributeRegistry registry)	Creates an evaluator that resolves accessor paths through a registry.

Method Summary

Modifier and Type	Method	Description
boolean	eval(Condition condition, Subject against)	Evaluates a condition against a subject, restoring the previously bound subject afterwards so nested evaluations can reenter.
Boolean	visitAnd(Condition.And c)	Visits a conjunction.
Boolean	visitComparison(Condition.Comparison c)	Visits a comparison leaf.
Boolean	visitCount(Condition.Count c)	Visits a stream cardinality test.
Boolean	visitGroup(Condition.Group c)	Visits a parenthesized group.
Boolean	visitNot(Condition.Not c)	Visits a negation.
Boolean	visitOr(Condition.Or c)	Visits a disjunction.
Boolean	visitQuantifier(Condition.Quantifier c)	Visits a quantification over a sub-subject stream.
Boolean	visitSequence(Condition.Sequence c)	Visits an instruction-sequence pattern.
Boolean	visitTrue(Condition.True c)	Visits the constant-true leaf.

Methods inherited from class java.lang.Object

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

Constructor Detail

ConditionEvaluator

public ConditionEvaluator(AttributeRegistry registry)

Creates an evaluator that resolves accessor paths through a registry.

Parameters:

registry - the attribute resolvers to navigate with

Method Detail

eval

public boolean eval(Condition condition,
                    Subject against)

Evaluates a condition against a subject, restoring the previously bound subject afterwards so nested evaluations can reenter.

Parameters:

condition - the condition to interpret

against - the subject to bind while interpreting

Returns:

true if the condition holds

visitAnd

public Boolean visitAnd(Condition.And c)

Description copied from interface: Condition.Visitor

Visits a conjunction.

Specified by:

visitAnd in interface Condition.Visitor<Boolean>

Parameters:

c - the node

Returns:

the visitor result

visitOr

public Boolean visitOr(Condition.Or c)

Description copied from interface: Condition.Visitor

Visits a disjunction.

Specified by:

visitOr in interface Condition.Visitor<Boolean>

Parameters:

c - the node

Returns:

the visitor result

visitNot

public Boolean visitNot(Condition.Not c)

Description copied from interface: Condition.Visitor

Visits a negation.

Specified by:

visitNot in interface Condition.Visitor<Boolean>

Parameters:

c - the node

Returns:

the visitor result

visitGroup

public Boolean visitGroup(Condition.Group c)

Description copied from interface: Condition.Visitor

Visits a parenthesized group.

Specified by:

visitGroup in interface Condition.Visitor<Boolean>

Parameters:

c - the node

Returns:

the visitor result

visitTrue

public Boolean visitTrue(Condition.True c)

Description copied from interface: Condition.Visitor

Visits the constant-true leaf.

Specified by:

visitTrue in interface Condition.Visitor<Boolean>

Parameters:

c - the node

Returns:

the visitor result

visitComparison

public Boolean visitComparison(Condition.Comparison c)

Description copied from interface: Condition.Visitor

Visits a comparison leaf.

Specified by:

visitComparison in interface Condition.Visitor<Boolean>

Parameters:

c - the node

Returns:

the visitor result

visitQuantifier

public Boolean visitQuantifier(Condition.Quantifier c)

Description copied from interface: Condition.Visitor

Visits a quantification over a sub-subject stream.

Specified by:

visitQuantifier in interface Condition.Visitor<Boolean>

Parameters:

c - the node

Returns:

the visitor result

visitCount

public Boolean visitCount(Condition.Count c)

Description copied from interface: Condition.Visitor

Visits a stream cardinality test.

Specified by:

visitCount in interface Condition.Visitor<Boolean>

Parameters:

c - the node

Returns:

the visitor result

visitSequence

public Boolean visitSequence(Condition.Sequence c)

Description copied from interface: Condition.Visitor

Visits an instruction-sequence pattern.

Specified by:

visitSequence in interface Condition.Visitor<Boolean>

Parameters:

c - the node

Returns:

the visitor result