Package ai.timefold.solver.core.impl.heuristic.move

Class AbstractUndoMove<Solution_>

java.lang.Object

ai.timefold.solver.core.impl.heuristic.move.AbstractUndoMove<Solution_>

Type Parameters:

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

All Implemented Interfaces:

Move<Solution_>

Direct Known Subclasses:

ListRuinRecreateUndoMove, RecordedUndoMove, RuinRecreateUndoMove, UndoKOptListMove

public abstract class AbstractUndoMove<Solution_>
extends Object
implements Move<Solution_>

Abstract superclass for Move, suggested starting point to implement undo moves when not using AbstractSimplifiedMove. Unless raw performance is a concern, consider using AbstractSimplifiedMove instead.

See Also:

• Move

Field Summary

Fields

Modifier and Type	Field	Description
protected final Move<Solution_>	parentMove

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractUndoMove(Move<Solution_> parentMove)

Method Summary

Modifier and Type	Method	Description
final Move<Solution_>	doMove(ScoreDirector<Solution_> scoreDirector)	Does the move (which indirectly affects the ScoreDirector.getWorkingSolution()).
protected abstract void	doMoveOnGenuineVariables(ScoreDirector<Solution_> scoreDirector)	Like doMoveOnly(ScoreDirector) but without the ScoreDirector.triggerVariableListeners() call (because doMoveOnly(ScoreDirector) already does that).
final void	doMoveOnly(ScoreDirector<Solution_> scoreDirector)	As defined by Move.doMove(ScoreDirector), but does not return an undo move.
final Collection<?>	getPlanningEntities()	Returns all planning entities that are being changed by this move.
final Collection<?>	getPlanningValues()	Returns all planning values that entities are being assigned to by this move.
String	getSimpleMoveTypeDescription()	Describes the move type for statistical purposes.
final boolean	isMoveDoable(ScoreDirector<Solution_> scoreDirector)	Called before a move is evaluated to decide whether the move can be done and evaluated.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface ai.timefold.solver.core.impl.heuristic.move.Move

rebase

Field Details

parentMove

protected final Move<Solution_> parentMove

Constructor Details

AbstractUndoMove

protected AbstractUndoMove(Move<Solution_> parentMove)

Method Details

isMoveDoable

public final boolean isMoveDoable(ScoreDirector<Solution_> scoreDirector)

Description copied from interface: Move

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 PlanningSolution.
• Either it's simply not possible to do (for example due to built-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.

Specified by:

isMoveDoable in interface Move<Solution_>

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.

doMove

public final Move<Solution_> doMove(ScoreDirector<Solution_> scoreDirector)

Description copied from interface: Move

Does the move (which indirectly affects the ScoreDirector.getWorkingSolution()). When the working solution is modified, the ScoreDirector must be correctly notified (through ScoreDirector.beforeVariableChanged(Object, String) and ScoreDirector.afterVariableChanged(Object, String)), otherwise later calculated Scores will be corrupted.

This method must end with calling ScoreDirector.triggerVariableListeners() to ensure all shadow variables are updated.

This method must return an undo move, so the move can be evaluated and then be undone without resulting into a permanent change in the solution.

Specified by:

doMove in interface Move<Solution_>

Parameters:

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

Returns:

an undoMove which does the exact opposite of this move

doMoveOnly

public final void doMoveOnly(ScoreDirector<Solution_> scoreDirector)

Description copied from interface: Move

As defined by Move.doMove(ScoreDirector), but does not return an undo move.

Specified by:

doMoveOnly in interface Move<Solution_>

Parameters:

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

doMoveOnGenuineVariables

protected abstract void doMoveOnGenuineVariables(ScoreDirector<Solution_> scoreDirector)

Like doMoveOnly(ScoreDirector) but without the ScoreDirector.triggerVariableListeners() call (because doMoveOnly(ScoreDirector) already does that).

Parameters:

scoreDirector - never null

getPlanningEntities

public final Collection<?> getPlanningEntities()

Description copied from interface: Move

Returns all planning entities that are being changed by this move. Required for AcceptorType.ENTITY_TABU.

This method is only called after Move.doMove(ScoreDirector) (which might affect the return values).

Duplicate 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.

Specified by:

getPlanningEntities in interface Move<Solution_>

Returns:

never null

getPlanningValues

public final Collection<?> getPlanningValues()

Description copied from interface: Move

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

This method is only called after Move.doMove(ScoreDirector) (which might affect the return values).

Duplicate 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.

Specified by:

getPlanningValues in interface Move<Solution_>

Returns:

never null

getSimpleMoveTypeDescription

public String getSimpleMoveTypeDescription()

Description copied from interface: Move

Describes the move type for statistical purposes. For example "ChangeMove(Process.computer)".

The format is not formalized. Never parse the String returned by this method.

Specified by:

getSimpleMoveTypeDescription in interface Move<Solution_>

Returns:

never null

toString

public String toString()

Overrides:

toString in class Object