javax.constraints
Interface Constraint

All Known Implementing Classes:

AbstractConstraint, ConstraintElementAtOnSets, ConstraintFalse, ConstraintGlobalCardinality, ConstraintMax, ConstraintMin, ConstraintNotAllEqual, ConstraintTable, ConstraintTraceVar, ConstraintTrue

public interface Constraint

The interface Constraint defines a generic interface for all constraints that could be created and posted within the Problem. Concrete constraints can be defined in two ways:

• explicitly in the interface Problem such as "allDifferent"
• implicitly inside constrained expressions such as var1.eq(var2).

The interface Problem includes only commonly used and de-facto standardized global constraints in their most popular forms. This API assumes that there will be a library of global constraints that implements the interface Constraint and follows the guidelines of the Global Constraint Catalog.

Method Summary

Constraint	and(Constraint c) Returns an "AND" Constraint.
VarBool	asBool() This method returns a Var variable that is equal 1 if the constraint is satisfied and equals 0 if it is violated.
java.lang.Object	getImpl() This method should be defined by a concrete solver implementation.
java.lang.String	getName() Returns the name of this object.
java.lang.Object	getObject() This method may be used to get an attached Business Object for this object.
Problem	getProblem() Return a problem to which this object belongs
Constraint	implies(Constraint c) Returns a Constraint that states the implication: this => c.
Constraint	negation() Returns a Constraint that is satisfied if and only if this constraint is not satisfied.
Constraint	or(Constraint c) Returns an "OR" Constraint.
void	post() This method is used to post the constraint.
void	post(ConsistencyLevel consistencyLevel) This method is used to post the constraint.
void	setImpl(java.lang.Object impl) This method defines an Object that represents an actual implementation of this object inside a concrete solver.
void	setName(java.lang.String name) Sets the name of this object.
void	setObject(java.lang.Object obj) This method may be used to attach a business object to this object.

Method Detail

and

Constraint and(Constraint c)

Returns an "AND" Constraint. The Constraint "AND" is satisfied if both of the Constraints "this" and "c" are satisfied. The Constraint "AND" is not satisfied if at least one of the Constraints "this" or "c" is not satisfied.

Parameters:

c - the Constraint which is part of the new "AND" Constraint

Returns:

a Constraint "AND" between the Constraints "this" and "c2".

asBool

VarBool asBool()

This method returns a Var variable that is equal 1 if the constraint is satisfied and equals 0 if it is violated.

Returns:

Var with a domain [0;1]: a 1 value indicates the constraint is satisfied, a 0 value indicates the constraint is violated.

getImpl

java.lang.Object getImpl()

This method should be defined by a concrete solver implementation. This method returns an Object that represents an actual implementation of this object inside an underlying solver.

Returns:

an Object that represents an actual implementation of this Constrained Object inside an underlying solver.

getName

java.lang.String getName()

Returns the name of this object.

Returns:

the name of this object.

getObject

java.lang.Object getObject()

This method may be used to get an attached Business Object for this object.

Returns:

the Business Object attached to this object.

getProblem

Problem getProblem()

Return a problem to which this object belongs

Returns:

a problem to which this object belongs

implies

Constraint implies(Constraint c)

Returns a Constraint that states the implication: this => c. In other words, if this constraint is satisfied, then constraint "c" should also be satisfied.

Parameters:

c - the Constraint in the implication.

Returns:

a Constraint that means this => c (if this then c).

negation

Constraint negation()

Returns a Constraint that is satisfied if and only if this constraint is not satisfied.

Returns:

a Constraint that is satisfied if and only if this constraint is not satisfied.

or

Constraint or(Constraint c)

Returns an "OR" Constraint. The Constraint "OR" is satisfied if either of the Constraints "this" and "c" is satisfied. The Constraint "OR" is not satisfied if both of the Constraints "this" and "c" are not satisfied.

Parameters:

c - the Constraint which is part of the new "OR" Constraint

Returns:

a Constraint "OR" between the Constraints "this" and "c".

post

void post()

This method is used to post the constraint. The constraint posting may do two things: 1) initial constraint propagation will be executed; 2) the constraint will be memorized and wait for notification events when the variables it controls are changed. The actual posting logic depends on an underlying CP solver. If the posting was unsuccessful, this method throws a runtime exception. A user may put constraint posting in a try-catch block to react to posting failures.

Throws:

java.lang.RuntimeException - if a failure happened during the posting

post

void post(ConsistencyLevel consistencyLevel)

This method is used to post the constraint. Additionally to post() this methods specifies a particular level of consistency that will be selected by an implementation to control the propagation strength of this constraint.

Parameters:

consistencyLevel -

Throws:

java.lang.RuntimeException - if a failure happened during the posting

setImpl

void setImpl(java.lang.Object impl)

This method defines an Object that represents an actual implementation of this object inside a concrete solver.

Parameters:

impl - the Object that represents an actual implementation of this object inside a implementation solver.

setName

void setName(java.lang.String name)

Sets the name of this object.

Parameters:

name - the name for this object.

setObject

void setObject(java.lang.Object obj)

This method may be used to attach a business object to this object.

Parameters:

obj - the business object being attached.