org.optaplanner.core.impl.domain.variable.listener

Interface VariableListener<Entity_>

All Superinterfaces:

Supply

All Known Subinterfaces:

CustomShadowVariable.NullVariableListener, StatefulVariableListener<Entity_>

All Known Implementing Classes:

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

public interface VariableListener<Entity_>
extends Supply

Changes shadow variables when a genuine planning variable changes.

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

Each ScoreDirector has a different VariableListener instance, so it can be stateful. If it is stateful, it must implement StatefulVariableListener.

Method Summary

Modifier and Type	Method and 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 boolean	requiresUniqueEntityEvents() When set to true, this has a slight performance loss in Planner.

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