Package org.optaplanner.core.api.domain.variable

Interface VariableListener<Entity_>

Type Parameters:

Entity_ -

All Superinterfaces:

AutoCloseable, Closeable

All Known Subinterfaces:

CustomShadowVariable.NullVariableListener, SourcedVariableListener<Entity_>, StatefulVariableListener<Entity_>, VariableListener<Entity_>

All Known Implementing Classes:

AnchorVariableListener, CollectionInverseVariableListener, ExternalizedAnchorVariableSupply, ExternalizedCollectionInverseVariableSupply, ExternalizedSingletonInverseVariableSupply, SingletonInverseVariableListener, VariableListenerAdapter

public interface VariableListener<Entity_>
extends Closeable

Changes shadow variables when a genuine planning variable changes.

Important: it must only change the shadow variable(s) for which it's configured! It should never change a genuine variable or a problem fact. It can change its shadow variable(s) on multiple entity instances (for example: an arrivalTime change affects all trailing entities too).

It is recommended that implementations be kept stateless. If state must be implemented, implementations may need to override the default methods (resetWorkingSolution(ScoreDirector), close()).

Method Summary

Modifier and Type	Method	Description
void	afterEntityAdded(ScoreDirector scoreDirector, Entity_ entity)
void	afterEntityRemoved(ScoreDirector scoreDirector, Entity_ entity)
void	afterVariableChanged(ScoreDirector scoreDirector, Entity_ entity)
void	beforeEntityAdded(ScoreDirector scoreDirector, Entity_ entity)
void	beforeEntityRemoved(ScoreDirector scoreDirector, Entity_ entity)
void	beforeVariableChanged(ScoreDirector scoreDirector, Entity_ entity)
default void	close()
default boolean	requiresUniqueEntityEvents()	When set to true, this has a slight performance loss in Planner.
default void	resetWorkingSolution(ScoreDirector scoreDirector)	Called when the entire working solution changes.

Method Detail

requiresUniqueEntityEvents

default boolean requiresUniqueEntityEvents()

When set to true, this has a slight performance loss in Planner. When set to false, it's often easier to make the listener implementation correct and fast.

Returns:

true to guarantee that each of the before/after methods will only be called once per entity instance per operation type (add, change or remove).

beforeEntityAdded

void beforeEntityAdded(ScoreDirector scoreDirector,
                       Entity_ entity)

Parameters:

scoreDirector - never null

entity - never null

afterEntityAdded

void afterEntityAdded(ScoreDirector scoreDirector,
                      Entity_ entity)

Parameters:

scoreDirector - never null

entity - never null

beforeVariableChanged

void beforeVariableChanged(ScoreDirector scoreDirector,
                           Entity_ entity)

Parameters:

scoreDirector - never null

entity - never null

afterVariableChanged

void afterVariableChanged(ScoreDirector scoreDirector,
                          Entity_ entity)

Parameters:

scoreDirector - never null

entity - never null

beforeEntityRemoved

void beforeEntityRemoved(ScoreDirector scoreDirector,
                         Entity_ entity)

Parameters:

scoreDirector - never null

entity - never null

afterEntityRemoved

void afterEntityRemoved(ScoreDirector scoreDirector,
                        Entity_ entity)

Parameters:

scoreDirector - never null

entity - never null

resetWorkingSolution

default void resetWorkingSolution(ScoreDirector scoreDirector)

Called when the entire working solution changes. In this event, the other before..()/after...() methods will not be called. At this point, implementations should clear state, if any.

Parameters:

scoreDirector - never null

close

default void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable