Package org.drools.core.base.evaluators

Interface EvaluatorDefinition

All Superinterfaces:

org.kie.api.runtime.rule.EvaluatorDefinition, Externalizable, Serializable

All Known Implementing Classes:

AfterEvaluatorDefinition, BeforeEvaluatorDefinition, CoincidesEvaluatorDefinition, DuringEvaluatorDefinition, FinishedByEvaluatorDefinition, FinishesEvaluatorDefinition, IncludesEvaluatorDefinition, MatchesEvaluatorsDefinition, MeetsEvaluatorDefinition, MetByEvaluatorDefinition, OverlappedByEvaluatorDefinition, OverlapsEvaluatorDefinition, SetEvaluatorsDefinition, SoundslikeEvaluatorsDefinition, StartedByEvaluatorDefinition, StartsEvaluatorDefinition, StrEvaluatorDefinition

public interface EvaluatorDefinition
extends Externalizable, org.kie.api.runtime.rule.EvaluatorDefinition

An evaluator definition interface that allows for pluggable evaluator implementation. This interface is the register entry point for all available evaluators and describes all evaluator capabilities

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	EvaluatorDefinition.Target	An enum for the target of the evaluator

Method Summary

Modifier and Type	Method	Description
Evaluator	getEvaluator(ValueType type, String operatorId, boolean isNegated, String parameterText)	Returns the evaluator instance for the given type and the defined parameterText
Evaluator	getEvaluator(ValueType type, String operatorId, boolean isNegated, String parameterText, EvaluatorDefinition.Target leftTarget, EvaluatorDefinition.Target rightTarget)	Returns the evaluator instance for the given type and the defined parameterText
Evaluator	getEvaluator(ValueType type, Operator operator)	Returns the evaluator instance for the given type and the defined parameterText
Evaluator	getEvaluator(ValueType type, Operator operator, String parameterText)	Returns the evaluator instance for the given type and the defined parameterText
String[]	getEvaluatorIds()	Returns the list of identifies this evaluator implementation supports
EvaluatorDefinition.Target	getTarget()	There are evaluators that operate on *fact* attributes, evaluators that operate on *fact handle* attributes, and evaluators that operate on both.
boolean	isNegatable()	My apologies to English speakers if the word "negatable" does not exist. :) This method returns true if this evaluator supports negation.
boolean	supportsType(ValueType type)	Returns true in case this evaluator supports operations over values of that specific type.

Methods inherited from interface java.io.Externalizable

readExternal, writeExternal

Method Detail

getEvaluatorIds

String[] getEvaluatorIds()

Returns the list of identifies this evaluator implementation supports

Returns:

isNegatable

boolean isNegatable()

My apologies to English speakers if the word "negatable" does not exist. :) This method returns true if this evaluator supports negation. Example: the "matches" operator supports "not matches" and so is "negatable" (!?)

Returns:

getEvaluator

Evaluator getEvaluator(ValueType type,
                       String operatorId,
                       boolean isNegated,
                       String parameterText,
                       EvaluatorDefinition.Target leftTarget,
                       EvaluatorDefinition.Target rightTarget)

Returns the evaluator instance for the given type and the defined parameterText

Parameters:

type - the type of the attributes this evaluator will operate on. This is important because the evaluator may do optimisations and type coercion based on the types it is evaluating. It is also possible that this evaluator does not support a given type.

operatorId - the string identifier of the evaluator

isNegated - true if the evaluator instance to be returned is the negated version of the evaluator.

parameterText - some evaluators support parameters and these parameters are defined as a String that is parsed by the evaluator itself.

leftTarget - the target of the evaluator on the Left side, i.e., on Rete terms, the previous binding or the actual value on the right side of the operator.

rightTarget - the target of the evaluator on the Right side, i.e., on Rete terms, the current pattern field.

Returns:

an Evaluator instance capable of evaluating expressions between values of the given type, or null in case the type is not supported.

getEvaluator

Evaluator getEvaluator(ValueType type,
                       String operatorId,
                       boolean isNegated,
                       String parameterText)

Returns the evaluator instance for the given type and the defined parameterText

Parameters:

type - the type of the attributes this evaluator will operate on. This is important because the evaluator may do optimisations and type coercion based on the types it is evaluating. It is also possible that this evaluator does not support a given type.

operatorId - the string identifier of the evaluator

isNegated - true if the evaluator instance to be returned is the negated version of the evaluator.

parameterText - some evaluators support parameters and these parameters are defined as a String that is parsed by the evaluator itself.

Returns:

an Evaluator instance capable of evaluating expressions between values of the given type, or null in case the type is not supported.

getEvaluator

Evaluator getEvaluator(ValueType type,
                       Operator operator,
                       String parameterText)

Returns the evaluator instance for the given type and the defined parameterText

Parameters:

type - the type of the attributes this evaluator will operate on. This is important because the evaluator may do optimisations and type coercion based on the types it is evaluating. It is also possible that this evaluator does not support a given type.

operator - the operator implemented by the evaluator

parameterText - some evaluators support parameters and these parameters are defined as a String that is parsed by the evaluator itself.

Returns:

an Evaluator instance capable of evaluating expressions between values of the given type, or null in case the type is not supported.

getEvaluator

Evaluator getEvaluator(ValueType type,
                       Operator operator)

Returns the evaluator instance for the given type and the defined parameterText

Parameters:

type - the type of the attributes this evaluator will operate on. This is important because the evaluator may do optimisations and type coercion based on the types it is evaluating. It is also possible that this evaluator does not support a given type.

operator - the operator implemented by the evaluator

Returns:

an Evaluator instance capable of evaluating expressions between values of the given type, or null in case the type is not supported.

supportsType

boolean supportsType(ValueType type)

Returns true in case this evaluator supports operations over values of that specific type.

Parameters:

type -

Returns:

getTarget

EvaluatorDefinition.Target getTarget()

There are evaluators that operate on *fact* attributes, evaluators that operate on *fact handle* attributes, and evaluators that operate on both. This method returns the target of the current evaluator.

Returns:

true if this evaluator operates on fact handle attributes and false if it operates on fact attributes