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

Interface VariableListener<Solution_,Entity_>

Type Parameters:

Solution_ - the solution type, the class with the PlanningSolution annotation

Entity_ -

All Superinterfaces:

AutoCloseable, Closeable

All Known Subinterfaces:

CustomShadowVariable.NullVariableListener, SourcedVariableListener<Solution_,Entity_>

All Known Implementing Classes:

AnchorVariableListener, CollectionInverseVariableListener, ExternalizedAnchorVariableSupply, ExternalizedCollectionInverseVariableSupply, ExternalizedSingletonInverseVariableSupply, SingletonInverseVariableListener

public interface VariableListener<Solution_,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<Solution_> scoreDirector, Entity_ entity)
void	afterEntityRemoved(ScoreDirector<Solution_> scoreDirector, Entity_ entity)
void	afterVariableChanged(ScoreDirector<Solution_> scoreDirector, Entity_ entity)
void	beforeEntityAdded(ScoreDirector<Solution_> scoreDirector, Entity_ entity)
void	beforeEntityRemoved(ScoreDirector<Solution_> scoreDirector, Entity_ entity)
void	beforeVariableChanged(ScoreDirector<Solution_> scoreDirector, Entity_ entity)
default void	close()	Called before this VariableListener is thrown away and not used anymore.
default boolean	requiresUniqueEntityEvents()	When set to true, this has a slight performance loss in Planner.
default void	resetWorkingSolution(ScoreDirector<Solution_> 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<Solution_> scoreDirector,
                       Entity_ entity)

Parameters:

scoreDirector - never null

entity - never null

afterEntityAdded

void afterEntityAdded(ScoreDirector<Solution_> scoreDirector,
                      Entity_ entity)

Parameters:

scoreDirector - never null

entity - never null

beforeVariableChanged

void beforeVariableChanged(ScoreDirector<Solution_> scoreDirector,
                           Entity_ entity)

Parameters:

scoreDirector - never null

entity - never null

afterVariableChanged

void afterVariableChanged(ScoreDirector<Solution_> scoreDirector,
                          Entity_ entity)

Parameters:

scoreDirector - never null

entity - never null

beforeEntityRemoved

void beforeEntityRemoved(ScoreDirector<Solution_> scoreDirector,
                         Entity_ entity)

Parameters:

scoreDirector - never null

entity - never null

afterEntityRemoved

void afterEntityRemoved(ScoreDirector<Solution_> scoreDirector,
                        Entity_ entity)

Parameters:

scoreDirector - never null

entity - never null

resetWorkingSolution

default void resetWorkingSolution(ScoreDirector<Solution_> 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()

Called before this VariableListener is thrown away and not used anymore.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable