org.optaplanner.core.impl.move
Interface Move

All Known Implementing Classes:

ChainedChangeMove, ChainedSwapMove, ChangeMove, CompositeMove, PillarSwapMove, SubChainChangeMove, SubChainReversingChangeMove, SubChainReversingSwapMove, SubChainSwapMove, SwapMove

public interface Move

A Move represents a change of 1 or more planning variables of 1 or more planning entities in the Solution.

Usually the move holds a direct reference to each planning entity of the Solution that it will change when doMove(ScoreDirector) is called. On that change it should also notify the ScoreDirector accordingly.

A Move should implement Object.equals(Object) and Object.hashCode().

Method Summary

Move	createUndoMove(ScoreDirector scoreDirector) Called before the move is done, so the move can be evaluated and then be undone without resulting into a permanent change in the solution.
void	doMove(ScoreDirector scoreDirector) Does the Move and updates the Solution and its ScoreDirector accordingly.
Collection<? extends Object>	getPlanningEntities() Returns all planning entities that are being changed by this move.
Collection<? extends Object>	getPlanningValues() Returns all planning values that entities are being assigned to by this move.
boolean	isMoveDoable(ScoreDirector scoreDirector) Called before a move is evaluated to decide whether the move can be done and evaluated.

Method Detail

isMoveDoable

boolean isMoveDoable(ScoreDirector scoreDirector)

Called before a move is evaluated to decide whether the move can be done and evaluated. A Move is not doable if:

• Either doing it would change nothing in the Solution.
• Either it's simply not possible to do (for example due to build-in hard constraints).

It is recommended to keep this method implementation simple: do not use it in an attempt to satisfy normal hard and soft constraints.

Although you could also filter out non-doable moves in for example the MoveSelector or MoveListFactory, this is not needed as the Solver will do it for you.

Parameters:

scoreDirector - the ScoreDirector not yet modified by the move.

Returns:

true if the move achieves a change in the solution and the move is possible to do on the solution.

createUndoMove

Move createUndoMove(ScoreDirector scoreDirector)

Called before the move is done, so the move can be evaluated and then be undone without resulting into a permanent change in the solution.

Parameters:

scoreDirector - the ScoreDirector not yet modified by the move.

Returns:

an undoMove which does the exact opposite of this move.

doMove

void doMove(ScoreDirector scoreDirector)

Does the Move and updates the Solution and its ScoreDirector accordingly. When the Solution is modified, the ScoreDirector should be correctly notified, otherwise later calculated Scores can be corrupted.

Parameters:

scoreDirector - never null, the ScoreDirector that needs to get notified of the changes.

getPlanningEntities

Collection<? extends Object> getPlanningEntities()

Returns all planning entities that are being changed by this move. Required for AcceptorConfig.AcceptorType#PLANNING_ENTITY_TABU.

Duplicates entries in the returned Collection are best avoided. The returned Collection is recommended to be in a stable order. For example: use List or LinkedHashSet, but not HashSet.

Returns:

never null

getPlanningValues

Collection<? extends Object> getPlanningValues()

Returns all planning values that entities are being assigned to by this move. Required for AcceptorConfig.AcceptorType#PLANNING_VALUE_TABU.

Duplicates entries in the returned Collection are best avoided. The returned Collection is recommended to be in a stable order. For example: use List or LinkedHashSet, but not HashSet.

Returns:

never null