org.cpsolver.studentsct.model

Class Request

java.lang.Object

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

org.cpsolver.ifs.assignment.context.VariableWithContext<Request,Enrollment,Request.RequestContext>

org.cpsolver.studentsct.model.Request

All Implemented Interfaces:

Comparable<Request>, CanHoldContext, HasAssignmentContext<Request,Enrollment,Request.RequestContext>

Direct Known Subclasses:

CourseRequest, FreeTimeRequest

public abstract class Request
extends VariableWithContext<Request,Enrollment,Request.RequestContext>

Representation of a request of a student for a course(s) or a free time. This can be either CourseRequest or FreeTimeRequest. Each request contains id, priority, weight, and a student. A request can be also marked as alternative.

For each student, all non-alternative requests should be satisfied (an enrollment is assigned to a request). If not, an alternative request can be assigned instead of a non-alternative course request. In the case when only one of two requests can be assigned, the one with the lowest priority is preferred.

Version:

StudentSct 1.3 (Student Sectioning)
Copyright (C) 2007 - 2014 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	Request.RequestContext
static class	Request.RequestPriority Importance of the request for the student to progress towards his/her degree.

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	sCacheValues True means that method Variable.values() will cache its results.

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

iIndex, iValue

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

sMaxSize

Constructor Summary

Constructors

Constructor and Description
Request(long id, int priority, boolean alternative, Student student) Constructor

Method Summary

Modifier and Type	Method and Description
int	compareTo(Request r) Compare to requests, non-alternative requests go first, otherwise use priority (a request with lower priority goes first)
abstract List<Enrollment>	computeEnrollments(Assignment<Request,Enrollment> assignment) Compute available enrollments
Request.RequestContext	createAssignmentContext(Assignment<Request,Enrollment> assignment) Create a new assignment context for the given assignment.
boolean	equals(Object o)
abstract double	getBound() Get bound, i.e., the value of the best possible enrollment
long	getId() Request id
abstract float	getMinCredit() Smallest credit provided by this request
int	getPriority() Request priority -- if there is a choice, request with lower priority is more preferred to be assigned
abstract Request.RequestPriority	getRequestPriority() Importance of the request.
Student	getStudent() Student to which this request belongs
double	getWeight() Request weight, set by default to 1.0, defines the amount of space which will be taken in the section by this request.
boolean	hasChildren() Check if this request is CourseRequest and a parent of some other course
boolean	hasCourse(Course course) Check if this request is CourseRequest and contains the given course.
int	hashCode()
boolean	hasSelection() Return true if this request has any selection
boolean	isAlternative() True, if the request is alternative (alternative request can be assigned instead of a non-alternative course requests, if it is left unassigned)
boolean	isAssigned(Assignment<Request,Enrollment> assignment) Return true if request is assigned.
boolean	isCritical() Deprecated.
boolean	isMPP() Return true if this request can track MPP
void	setPriority(int priority) Set request priority
void	setWeight(double weight) Set request weight.
List<Enrollment>	values(Assignment<Request,Enrollment> assignment) Domain of this variable -- list of available enrollments.
void	variableAssigned(Assignment<Request,Enrollment> assignment, long iteration, Enrollment enrollment) Assign given enrollment to this request.
void	variableUnassigned(Assignment<Request,Enrollment> assignment, long iteration, Enrollment enrollment) Unassign currently assigned enrollment from this request.

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

getAssignmentContextReference, getContext, getContext, setAssignmentContextReference, setModel

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

addContstraint, addVariableListener, assign, constraints, constraintVariables, getAssignment, getAssignment, getAssignments, getBestAssignment, getBestAssignmentIteration, getDescription, getExtra, getIndex, getInitialAssignment, getLastIteration, getModel, getName, getVariableListeners, hardConstraints, hasAssignment, hasAssignment, hasInitialAssignment, hasValues, removeContstraint, removeInitialValue, removeValue, removeVariableListener, setAssignment, setBestAssignment, setExtra, setIndex, setInitialAssignment, setLastIteration, setValues, softConstraints, toString, unassign, values

Methods inherited from class java.lang.Object

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

Field Detail

sCacheValues

public static boolean sCacheValues

True means that method Variable.values() will cache its results.

Constructor Detail

Request

public Request(long id,
               int priority,
               boolean alternative,
               Student student)

Constructor

Parameters:

id - course/free time request unique id

priority - request priority -- if there is a choice, request with lower priority is more preferred to be assigned

alternative - true if the request is alternative (alternative request can be assigned instead of a non-alternative course requests, if it is left unassigned)

student - student to which this request belongs

Method Detail

getId

public long getId()

Request id

Overrides:

getId in class Variable<Request,Enrollment>

Returns:

variable id

getPriority

public int getPriority()

Request priority -- if there is a choice, request with lower priority is more preferred to be assigned

Returns:

request priority

setPriority

public void setPriority(int priority)

Set request priority

Parameters:

priority - request priority

isAlternative

public boolean isAlternative()

True, if the request is alternative (alternative request can be assigned instead of a non-alternative course requests, if it is left unassigned)

Returns:

is alternative request

getStudent

public Student getStudent()

Student to which this request belongs

Returns:

student

compareTo

public int compareTo(Request r)

Compare to requests, non-alternative requests go first, otherwise use priority (a request with lower priority goes first)

Specified by:

compareTo in interface Comparable<Request>

Overrides:

compareTo in class Variable<Request,Enrollment>

computeEnrollments

public abstract List<Enrollment> computeEnrollments(Assignment<Request,Enrollment> assignment)

Compute available enrollments

Parameters:

assignment - current assignment

Returns:

list of all enrollments

values

public List<Enrollment> values(Assignment<Request,Enrollment> assignment)

Domain of this variable -- list of available enrollments. Method computeEnrollments(Assignment) is used.

Overrides:

values in class Variable<Request,Enrollment>

Parameters:

assignment - current assignment (if the domain is dependent on the current assignment)

Returns:

all possible values of this variable

variableAssigned

public void variableAssigned(Assignment<Request,Enrollment> assignment,
                             long iteration,
                             Enrollment enrollment)

Assign given enrollment to this request. This method also calls SctAssignment.assigned(Assignment, Enrollment) on for all the assignments of the enrollment.

Overrides:

variableAssigned in class Variable<Request,Enrollment>

Parameters:

assignment - current assignment

iteration - current iteration

enrollment - assigned value

variableUnassigned

public void variableUnassigned(Assignment<Request,Enrollment> assignment,
                               long iteration,
                               Enrollment enrollment)

Unassign currently assigned enrollment from this request. This method also calls SctAssignment.unassigned(Assignment, Enrollment) on for all the assignments of the current enrollment.

Overrides:

variableUnassigned in class Variable<Request,Enrollment>

Parameters:

assignment - current assignment

iteration - current iteration

enrollment - unassigned value

getBound

public abstract double getBound()

Get bound, i.e., the value of the best possible enrollment

Returns:

uppper bound

getWeight

public double getWeight()

Request weight, set by default to 1.0, defines the amount of space which will be taken in the section by this request.

Returns:

request weight

setWeight

public void setWeight(double weight)

Set request weight. It defines the amount of space which will be taken in the section by this request.

Parameters:

weight - request weight

isAssigned

public boolean isAssigned(Assignment<Request,Enrollment> assignment)

Return true if request is assigned.

Parameters:

assignment - current assignment

Returns:

true if this request is assigned

hashCode

public int hashCode()

Overrides:

hashCode in class Variable<Request,Enrollment>

equals

public boolean equals(Object o)

Overrides:

equals in class Variable<Request,Enrollment>

createAssignmentContext

public Request.RequestContext createAssignmentContext(Assignment<Request,Enrollment> 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

isMPP

public boolean isMPP()

Return true if this request can track MPP

Returns:

true if the request is course request and it either has an initial enrollment or some selected choices.

hasSelection

public boolean hasSelection()

Return true if this request has any selection

Returns:

true if the request is course request and has some selected choices.

getMinCredit

public abstract float getMinCredit()

Smallest credit provided by this request

isCritical

@Deprecated
public boolean isCritical()

Deprecated.

Is this request critical for the student to progress towards his/her degree

hasCourse

public boolean hasCourse(Course course)

Check if this request is CourseRequest and contains the given course.

hasChildren

public boolean hasChildren()

Check if this request is CourseRequest and a parent of some other course

getRequestPriority

public abstract Request.RequestPriority getRequestPriority()

Importance of the request. Higher priority requests are assigned before lower priority requests.