org.cpsolver.instructor.constraints

Class SameInstructorConstraint

java.lang.Object

org.cpsolver.ifs.model.Constraint<V,T>

org.cpsolver.ifs.assignment.context.ConstraintWithContext<TeachingRequest.Variable,TeachingAssignment,SameInstructorConstraint.Context>

org.cpsolver.instructor.constraints.SameInstructorConstraint

All Implemented Interfaces:

Comparable<Constraint<TeachingRequest.Variable,TeachingAssignment>>, CanHoldContext, HasAssignmentContext<TeachingRequest.Variable,TeachingAssignment,SameInstructorConstraint.Context>

public class SameInstructorConstraint
extends ConstraintWithContext<TeachingRequest.Variable,TeachingAssignment,SameInstructorConstraint.Context>

Same Instructor Constraint. Teaching requests linked with this constraint must/should have the same instructor assigned. If discouraged/prohibited, every pair of teaching requests should/must have a different instructor.

Version:

IFS 1.3 (Instructor Sectioning)
Copyright (C) 2016 Tomáš Müller
muller@unitime.org
http://muller.unitime.org

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not see http://www.gnu.org/licenses/.

Author:

Tomáš Müller

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	SameInstructorConstraint.Context Same Instructor Constraint Context.

Field Summary

Fields inherited from class org.cpsolver.ifs.model.Constraint

iConstraintListeners

Fields inherited from interface org.cpsolver.ifs.assignment.context.CanHoldContext

sMaxSize

Constructor Summary

Constructors

Constructor and Description
SameInstructorConstraint(Long id, String name, String preference) Constructor

Method Summary

Modifier and Type	Method and Description
void	computeConflicts(Assignment<TeachingRequest.Variable,TeachingAssignment> assignment, TeachingAssignment value, Set<TeachingAssignment> conflicts) The only method which has to be implemented by any constraint.
SameInstructorConstraint.Context	createAssignmentContext(Assignment<TeachingRequest.Variable,TeachingAssignment> assignment) Create a new assignment context for the given assignment.
Long	getConstraintId() Constraint id that was provided in the constructor
int	getCurrentPreference(Assignment<TeachingRequest.Variable,TeachingAssignment> assignment) Current constraint preference (if soft)
int	getCurrentPreference(Assignment<TeachingRequest.Variable,TeachingAssignment> assignment, TeachingAssignment value) Current constraint preference (if soft)
String	getName() Constraint's name -- for printing purposes
int	getPreference() Constraint preference that was provided in the constructor
boolean	isHard() Returns true if the constraint is hard.
boolean	isProhibited() Is prohibited?
boolean	isRequired() Is required?
boolean	isSatisfiedPair(Assignment<TeachingRequest.Variable,TeachingAssignment> assignment, TeachingAssignment a1, TeachingAssignment a2) Does a pair of teaching assignments satisfy this constraint?
String	toString()

Methods inherited from class org.cpsolver.ifs.assignment.context.ConstraintWithContext

assigned, getAssignmentContextReference, getContext, getContext, setAssignmentContextReference, setModel, unassigned

Methods inherited from class org.cpsolver.ifs.model.Constraint

addConstraintListener, addVariable, assignedVariables, compareTo, computeConflictsNoForwardCheck, constraintListeners, countAssignedVariables, countVariables, equals, getDescription, getId, getModel, hashCode, inConflict, isConsistent, removeConstraintListener, removeVariable, variables

Methods inherited from class java.lang.Object

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

Constructor Detail

SameInstructorConstraint

public SameInstructorConstraint(Long id,
                                String name,
                                String preference)

Constructor

Parameters:

id - constraint id

name - constrain (link) name

preference - preference (R for required, P for prohibited, etc.)

Method Detail

getConstraintId

public Long getConstraintId()

Constraint id that was provided in the constructor

Returns:

constraint id

getName

public String getName()

Description copied from class: Constraint

Constraint's name -- for printing purposes

Overrides:

getName in class Constraint<TeachingRequest.Variable,TeachingAssignment>

Returns:

constraint name

toString

public String toString()

Overrides:

toString in class Object

isRequired

public boolean isRequired()

Is required?

Returns:

true if the constraint is required

isProhibited

public boolean isProhibited()

Is prohibited?

Returns:

true if the constraint is prohibited

getPreference

public int getPreference()

Constraint preference that was provided in the constructor

Returns:

constraint preference

isHard

public boolean isHard()

Description copied from class: Constraint

Returns true if the constraint is hard. Only hard constraints are allowed to unassign a variable when there is a conflict with a value that is being assigned

Overrides:

isHard in class Constraint<TeachingRequest.Variable,TeachingAssignment>

Returns:

true if the constraint is hard

isSatisfiedPair

public boolean isSatisfiedPair(Assignment<TeachingRequest.Variable,TeachingAssignment> assignment,
                               TeachingAssignment a1,
                               TeachingAssignment a2)

Does a pair of teaching assignments satisfy this constraint?

Parameters:

assignment - current assignment

a1 - first teaching assignment

a2 - second teaching assignment

Returns:

True if the two assignments (of this constraint) have the same instructor (prohibited/preferred case) or a different instructor (prohibited/discouraged case).

computeConflicts

public void computeConflicts(Assignment<TeachingRequest.Variable,TeachingAssignment> assignment,
                             TeachingAssignment value,
                             Set<TeachingAssignment> conflicts)

Description copied from class: Constraint

The only method which has to be implemented by any constraint. It returns the values which needs to be unassigned in order to make this constraint consistent with the given value if it is assigned to its variable. The computed list of conflicting values is added to the given set of conflicts.

Specified by:

computeConflicts in class Constraint<TeachingRequest.Variable,TeachingAssignment>

Parameters:

assignment - current assignment

value - value to be assigned to its variable

conflicts - resultant set of conflicting values

getCurrentPreference

public int getCurrentPreference(Assignment<TeachingRequest.Variable,TeachingAssignment> assignment,
                                TeachingAssignment value)

Current constraint preference (if soft)

Parameters:

assignment - current assignment

value - proposed change

Returns:

change in the current preference value of this constraint

getCurrentPreference

public int getCurrentPreference(Assignment<TeachingRequest.Variable,TeachingAssignment> assignment)

Current constraint preference (if soft)

Parameters:

assignment - current assignment

Returns:

number of violated pairs weighted by the absolute value of the preference

createAssignmentContext

public SameInstructorConstraint.Context createAssignmentContext(Assignment<TeachingRequest.Variable,TeachingAssignment> assignment)

Description copied from interface: HasAssignmentContext

Create a new assignment context for the given assignment. If there are already some variables assigned in the value, the method should make sure that the context is appropriately initialized.

Parameters:

assignment - an assignment for which there needs to be an assignment context

Returns:

a new instance of the assignment context, filled according to the given assignment