org.jacop.constraints

Class IfThen

java.lang.Object

org.jacop.constraints.DecomposedConstraint<Constraint>

org.jacop.constraints.Constraint

org.jacop.constraints.PrimitiveConstraint

org.jacop.constraints.IfThen

All Implemented Interfaces:

SatisfiedPresent, StoreAware, UsesQueueVariable

public class IfThen
extends PrimitiveConstraint
implements UsesQueueVariable

Constraint if constraint1 then constraint2

Version:

4.9

Author:

Krzysztof Kuchcinski and Radoslaw Szymanek

Field Summary

Fields

Modifier and Type	Field and Description
PrimitiveConstraint	condC It specifies constraint condC in the IfThen constraint.
QueueForward<PrimitiveConstraint>	queueForward
PrimitiveConstraint	thenC It specifies constraint condC in the IfThen constraint.

Fields inherited from class org.jacop.constraints.PrimitiveConstraint

notConsistencyPruningEvents

Fields inherited from class org.jacop.constraints.Constraint

atomicExecution, consistencyPruningEvents, constraintScope, earlyTerminationOK, increaseWeight, numberId, scope, trace

Fields inherited from class org.jacop.constraints.DecomposedConstraint

queueIndex

Constructor Summary

Constructors

Constructor and Description
IfThen(PrimitiveConstraint condC, PrimitiveConstraint thenC) It constructs ifthen constraint.

Method Summary

Modifier and Type	Method and Description
void	consistency(Store store) It is a (most probably incomplete) consistency function which removes the values from variables domains.
int	getConsistencyPruningEvent(Var var) It retrieves the pruning event which causes reevaluation of the constraint.
int	getDefaultConsistencyPruningEvent()
protected int	getDefaultNotConsistencyPruningEvent()
int	getNestedPruningEvent(Var var, boolean mode) It retrieves the pruning event for which any composed constraint which uses this constraint should be evaluated.
int	getNotConsistencyPruningEvent(Var var) It retrieves the pruning event which causes reevaluation of the constraint notConsistency() function.
void	impose(Store store) It imposes the constraint in a given store.
void	include(Store store) It provide store for constraints that are not imposed but called from other constraints.
void	notConsistency(Store store) It makes pruning in such a way that constraint is notConsistent.
boolean	notSatisfied() It checks if constraint would be always not satisfied.
void	queueVariable(int level, Var variable) This is a function called to indicate which variable in a scope of constraint has changed.
boolean	satisfied() It checks if the constraint is satisfied.
String	toString() It produces a string representation of a constraint state.

Methods inherited from class org.jacop.constraints.PrimitiveConstraint

getDefaultNestedConsistencyPruningEvent, getDefaultNestedNotConsistencyPruningEvent, setNotConsistencyPruningEvent

Methods inherited from class org.jacop.constraints.Constraint

afc, arguments, cleanAfterFailure, decompose, getGuideConstraint, getGuideValue, getGuideVariable, grounded, grounded, id, impose, imposeDecomposition, increaseWeight, intArrayToString, long2int, numberArgs, removeConstraint, requiresMonotonicity, setConsistencyPruningEvent, setConstraintScope, setScope, setScope, setScope, setScope, setScope, setWatchedVariableGrounded, supplyGuideFeedback, updateAFC, watchedVariableGrounded

Methods inherited from class org.jacop.constraints.DecomposedConstraint

auxiliaryVariables, checkInput, checkInput, checkInputForDuplication, checkInputForDuplicationSkipSingletons, checkInputForNullness, checkInputForNullness, checkInputForNullness, derivative, getDubletonsSkipSingletons, imposeDecomposition

Methods inherited from class java.lang.Object

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

Field Detail

condC

public PrimitiveConstraint condC

It specifies constraint condC in the IfThen constraint.

thenC

public PrimitiveConstraint thenC

It specifies constraint condC in the IfThen constraint.

queueForward

public final QueueForward<PrimitiveConstraint> queueForward

Constructor Detail

IfThen

public IfThen(PrimitiveConstraint condC,
              PrimitiveConstraint thenC)

It constructs ifthen constraint.

Parameters:

condC - the condition of the ifthen constraint.

thenC - the constraint which must hold if the condition holds.

Method Detail

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.

notSatisfied

public boolean notSatisfied()

Description copied from class: PrimitiveConstraint

It checks if constraint would be always not satisfied.

Specified by:

notSatisfied in class PrimitiveConstraint

Returns:

true if constraint must be notSatisfied, false otherwise.

notConsistency

public void notConsistency(Store store)

Description copied from class: PrimitiveConstraint

It makes pruning in such a way that constraint is notConsistent. It removes values which always belong to a solution.

Specified by:

notConsistency in class PrimitiveConstraint

Parameters:

store - the constraint store in which context the notConsistency technique is evaluated.

getConsistencyPruningEvent

public int getConsistencyPruningEvent(Var var)

Description copied from class: Constraint

It retrieves the pruning event which causes reevaluation of the constraint.

Overrides:

getConsistencyPruningEvent in class Constraint

Parameters:

var - variable for which pruning event is retrieved

Returns:

it returns the int code of the pruning event (GROUND, BOUND, ANY, NONE)

getDefaultConsistencyPruningEvent

public int getDefaultConsistencyPruningEvent()

Specified by:

getDefaultConsistencyPruningEvent in class Constraint

getNotConsistencyPruningEvent

public int getNotConsistencyPruningEvent(Var var)

Description copied from class: PrimitiveConstraint

It retrieves the pruning event which causes reevaluation of the constraint notConsistency() function.

Overrides:

getNotConsistencyPruningEvent in class PrimitiveConstraint

Parameters:

var - for which pruning event is retrieved

Returns:

the int denoting the pruning event associated with given variable.

getNestedPruningEvent

public int getNestedPruningEvent(Var var,
                                 boolean mode)

Description copied from class: PrimitiveConstraint

It retrieves the pruning event for which any composed constraint which uses this constraint should be evaluated. This events are the ones which can change satisfied status?

Overrides:

getNestedPruningEvent in class PrimitiveConstraint

Parameters:

var - for which pruning event is retrieved

mode - decides if pruning event for consistency or nonconsistency is required.

Returns:

pruning event associated with the given variable for a given consistency mode.

getDefaultNotConsistencyPruningEvent

protected int getDefaultNotConsistencyPruningEvent()

Specified by:

getDefaultNotConsistencyPruningEvent in class PrimitiveConstraint

impose

public void impose(Store store)

Description copied from class: Constraint

It imposes the constraint in a given store.

Overrides:

impose in class PrimitiveConstraint

Parameters:

store - the constraint store to which the constraint is imposed to.

include

public void include(Store store)

Description copied from interface: StoreAware

It provide store for constraints that are not imposed but called from other constraints.

Specified by:

include in interface StoreAware

Overrides:

include in class PrimitiveConstraint

Parameters:

store - the constraint store in which context the constraint is executed.

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.

toString

public String toString()

Description copied from class: Constraint

It produces a string representation of a constraint state.

Overrides:

toString in class Constraint

queueVariable

public void queueVariable(int level,
                          Var variable)

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.

variable - variable which has changed.