org.cpsolver.instructor.constraints

Class SameLinkConstraint

java.lang.Object

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

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

org.cpsolver.instructor.constraints.SameLinkConstraint

All Implemented Interfaces:

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

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

Same Link Constraint. Much like the SameInstructorConstraint, but it is possible to assign multiple instructors to the teaching requests of the same link. It is, however, prohibited (or discouraged) for an instructor to teach have teaching requests than the ones of the link. In prohibited / discouraged variant, each request must / should get 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	SameLinkConstraint.Context Same Link 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
SameLinkConstraint(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.
SameLinkConstraint.Context	createAssignmentContext(Assignment<TeachingRequest.Variable,TeachingAssignment> assignment) Create a new assignment context for the given assignment.
Long	getConstraintId() Constraint id that was given 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?
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

SameLinkConstraint

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

Constructor

Parameters:

id - constraint id

name - link name

preference - constraint preference (R for required, etc.)

Method Detail

getConstraintId

public Long getConstraintId()

Constraint id that was given 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

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:

that is number of requests that are not of this link assigned to the instructors that have at least one request of this link if preferred; number of additional requests of this link given to the same instructor if discouraged

createAssignmentContext

public SameLinkConstraint.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