Package org.jacop.constraints

Class ValuePrecede

java.lang.Object
org.jacop.constraints.DecomposedConstraint<Constraint>
org.jacop.constraints.Constraint
org.jacop.constraints.ValuePrecede
All Implemented Interfaces:
SatisfiedPresent, Stateful, UsesQueueVariable
public class ValuePrecede extends Constraint implements UsesQueueVariable, Stateful, SatisfiedPresent

  • Field Details

    • idNumber

      static final AtomicInteger idNumber

    • store

      Store store

    • x

      public final IntVar[] x
      It specifies lists of variables for the constraint.

    • n

      private int n

    • s

      protected final int s
      It specifies values s and t for the constraint.

    • t

      protected final int t

    • alpha

      private TimeStamp<Integer> alpha

    • beta

      private TimeStamp<Integer> beta

    • gamma

      private TimeStamp<Integer> gamma

    • alphaValue

      private int alphaValue

    • betaValue

      private int betaValue

    • gammaValue

      private int gammaValue

    • firstConsistencyCheck

      private boolean firstConsistencyCheck

    • varQueue

      private LinkedHashSet<IntVar> varQueue

    • varMap

      private final Map<IntVar,Integer> varMap

  • Constructor Details

    • ValuePrecede

      public ValuePrecede(int s, int t, IntVar[] x)
      It constructs ValuePrecede.
      Parameters:
      s - value occuring first
      t - value occuring next
      x - list of arguments x's.

    • ValuePrecede

      public ValuePrecede(int s, int t, List<? extends IntVar> x)
      It constructs ValuePrecede.
      Parameters:
      s - value occuring first
      t - value occuring next
      x - list of arguments x's.

  • Method Details

    • impose

      public void impose(Store store)
      Description copied from class: Constraint
      It imposes the constraint in a given store.
      Overrides:
      impose in class Constraint
      Parameters:
      store - the constraint store to which the constraint is imposed to.

    • getDefaultConsistencyPruningEvent

      public int getDefaultConsistencyPruningEvent()
      Specified by:
      getDefaultConsistencyPruningEvent in class Constraint

    • consistency

      public void consistency(Store store)
      Description copied from class: Constraint
      It is a (most probably incomplete) consistency function which removes the values from variables domains. Only values which do not have any support in a solution space are removed.
      Specified by:
      consistency in class Constraint
      Parameters:
      store - constraint store within which the constraint consistency is being checked.

    • initialize

      private void initialize()

    • propagate

      private void propagate(int i)

    • updateBeta

      private void updateBeta()

    • checkGamma

      private void checkGamma(int i)

    • satisfied

      public boolean satisfied()
      Description copied from interface: SatisfiedPresent
      It checks if the constraint is satisfied. It can return false even if constraint is satisfied but not all variables in its scope are grounded. It needs to return true if all variables in its scope are grounded and constraint is satisfied.

      Implementations of this interface for constraints that are not PrimitiveConstraint may require constraint imposition and consistency check as a requirement to work correctly.

      Specified by:
      satisfied in interface SatisfiedPresent
      Returns:
      true if constraint is possible to verify that it is satisfied.

    • queueVariable

      public void queueVariable(int level, Var var)
      Description copied from class: Constraint
      This is a function called to indicate which variable in a scope of constraint has changed. It also indicates a store level at which the change has occurred.
      Overrides:
      queueVariable in class Constraint
      Parameters:
      level - the level of the store at which the change has occurred.
      var - variable which has changed.

    • removeLevel

      public void removeLevel(int level)
      Description copied from interface: Stateful
      This function is called in case of the backtrack, so a constraint can clear the queue of changed variables which is no longer valid. This function is called *before* all timestamps, variables, mutablevariables have reverted to their previous value.
      Specified by:
      removeLevel in interface Stateful
      Parameters:
      level - the level which is being removed.

    • toString

      public String toString()
      Description copied from class: Constraint
      It produces a string representation of a constraint state.
      Overrides:
      toString in class Constraint