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

Class CompositeMove<Solution_>

java.lang.Object

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

Type Parameters:

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

All Implemented Interfaces:

Move<Solution_>

public final class CompositeMove<Solution_>
extends Object
implements Move<Solution_>

A CompositeMove is composed out of multiple other moves.

Warning: each of moves in the moveList must not rely on the effect of a previous move in the moveList to create its undoMove correctly.

See Also:

• Move

Method Summary

Modifier and Type	Method	Description
static <Solution_, Move_ extends Move<Solution_>> Move<Solution_>	buildMove(List<Move_> moveList)
static <Solution_, Move_ extends Move<Solution_>> Move<Solution_>	buildMove(Move_... moves)
Move<Solution_>	doMove(ScoreDirector<Solution_> scoreDirector)	Does the move (which indirectly affects the ScoreDirector.getWorkingSolution()).
void	doMoveOnly(ScoreDirector<Solution_> scoreDirector)	As defined by Move.doMove(ScoreDirector), but does not return an undo move.
boolean	equals(Object other)
Move<Solution_>[]	getMoves()
Collection<?>	getPlanningEntities()	Returns all planning entities that are being changed by this move.
Collection<?>	getPlanningValues()	Returns all planning values that entities are being assigned to by this move.
String	getSimpleMoveTypeDescription()	Describes the move type for statistical purposes.
int	hashCode()
boolean	isMoveDoable(ScoreDirector<Solution_> scoreDirector)	Called before a move is evaluated to decide whether the move can be done and evaluated.
CompositeMove<Solution_>	rebase(ScoreDirector<Solution_> destinationScoreDirector)	Rebases a move from an origin ScoreDirector to another destination ScoreDirector which is usually on another Thread or JVM.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Details

buildMove

@SafeVarargs
public static <Solution_,
Move_ extends Move<Solution_>>
Move<Solution_> buildMove(Move_... moves)

Parameters:

moves - never null, sometimes empty. Do not modify this argument afterwards or the CompositeMove corrupts.

Returns:

never null

buildMove

public static <Solution_,
Move_ extends Move<Solution_>>
Move<Solution_> buildMove(List<Move_> moveList)

Parameters:

moveList - never null, sometimes empty

Returns:

never null

getMoves

public Move<Solution_>[] getMoves()

isMoveDoable

public 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 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 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

rebase

public CompositeMove<Solution_> rebase(ScoreDirector<Solution_> destinationScoreDirector)

Description copied from interface: Move

Rebases a move from an origin ScoreDirector to another destination ScoreDirector which is usually on another Thread or JVM. The new move returned by this method translates the entities and problem facts to the destination PlanningSolution of the destination ScoreDirector, That destination PlanningSolution is a deep planning clone (or an even deeper clone) of the origin PlanningSolution that this move has been generated from.

That new move does the exact same change as this move, resulting in the same PlanningSolution state, presuming that destination PlanningSolution was in the same state as the original PlanningSolution to begin with.

Generally speaking, an implementation of this method iterates through every entity and fact instance in this move, translates each one to the destination ScoreDirector with ScoreDirector.lookUpWorkingObject(Object) and creates a new move instance of the same move type, using those translated instances.

The destination PlanningSolution can be in a different state than the original PlanningSolution. So, rebasing can only depend on the identity of planning entities and problem facts, which are usually declared by a PlanningId on those classes. It must not depend on the state of the planning variables. One thread might rebase a move before, amid or after another thread does that same move instance.

This method is thread-safe.

Specified by:

rebase in interface Move<Solution_>

Parameters:

destinationScoreDirector - never null, the ScoreDirector.getWorkingSolution() that the new move should change the planning entity instances of.

Returns:

never null, a new move that does the same change as this move on another solution instance

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

getPlanningEntities

public 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 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

equals

public boolean equals(Object other)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object