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

Class NoChangeMove<Solution_>

java.lang.Object
ai.timefold.solver.core.impl.heuristic.move.AbstractMove<Solution_>
ai.timefold.solver.core.impl.heuristic.move.NoChangeMove<Solution_>
Type Parameters:
Solution_ - the solution type, the class with the PlanningSolution annotation
All Implemented Interfaces:
Move<Solution_>
public final class NoChangeMove<Solution_> extends AbstractMove<Solution_>
Makes no changes.

  • Field Details

  • Method Details

    • getInstance

      public static <Solution_> NoChangeMove<Solution_> getInstance()

    • 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.

      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.

    • doMoveOnGenuineVariables

      protected void doMoveOnGenuineVariables(ScoreDirector<Solution_> scoreDirector)
      Description copied from class: AbstractMove
      Like AbstractMove.doMoveOnly(ScoreDirector) but without the ScoreDirector.triggerVariableListeners() call (because AbstractMove.doMoveOnly(ScoreDirector) already does that).
      Specified by:
      doMoveOnGenuineVariables in class AbstractMove<Solution_>
      Parameters:
      scoreDirector - never null

    • rebase

      public Move<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.

      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.

      Returns:
      never null