org.decisiondeck.jmcda.structure.sorting.assignment
Interface IOrderedAssignmentsRead

All Superinterfaces:

IAssignmentsRead, IAssignmentsToMultipleRead, IOrderedAssignmentsToMultipleRead

All Known Subinterfaces:

IOrderedAssignments

All Known Implementing Classes:

OrderedAssignments, OrderedAssignmentsFiltering, OrderedAssignmentsForwarder, OrderedAssignmentsFromRead

public interface IOrderedAssignmentsRead
extends IAssignmentsRead, IOrderedAssignmentsToMultipleRead

A read-only interface for a set of assignments where one assignment is a mapping of an alternative to exactly one category among a set of ordered categories.

Equivalent to IAssignmentsRead to use when the categories the alternatives are assigned to are provided with a total ordering, thus can be sorted from worst to best without ex-æquo.

A set of such assignments can also be considered as a degenerate case of a set of assignments to multiple categories, where each alternative is assigned to exactly one category (which is a legal assignment to ''multiple'' categories), hence the inheritance relation. Objects implementing this interface however may only implement the degenerate case of the multiple categories case: it is impossible to satisfy both the contract for this interface (ensuring that every alternative is assigned to exactly one category) and the general case of the multiple categories interface (allowing an alternative to be assigned to more than one category). Having the inheritance relation permits to use objects implementing the single category case (this interface) for algorithms dealing with multiple categories assignments.

An ordered assignments object equals an other one iff they contain the same alternatives assigned to the same categories and contain the same set of overall categories in the same order. This definition is compatible with the definition of equality over ordered assignments to multiple categories objects.

This interface does not extend IOrderedAssignmentsWithCredibilitiesRead because it would involve automatic guess of an arbitrary constant credibility degree, e.g. one. This would then forbids an algorithm to clearly specify if it really uses credibility degrees as input or not. The user could think that an algorithm will not use the credibility degrees whereas it will use them, therefore making use of credibility numbers which have no real meaning.

Method Summary

NavigableSet<Category>

getCategories(Alternative alternative) Retrieves, if it exists, the category to which an alternative is assigned as a singleton set.

Methods inherited from interface org.decisiondeck.jmcda.structure.sorting.assignment.IAssignmentsRead

getCategory

Methods inherited from interface org.decisiondeck.jmcda.structure.sorting.assignment.IOrderedAssignmentsToMultipleRead

equals, getCategories

Methods inherited from interface org.decisiondeck.jmcda.structure.sorting.assignment.IAssignmentsToMultipleRead

getAlternatives, getAlternatives

Method Detail

getCategories

NavigableSet<Category> getCategories(Alternative alternative)

Retrieves, if it exists, the category to which an alternative is assigned as a singleton set. This method provides compatibility with the IOrderedAssignmentsToMultipleRead interface. The method IAssignmentsRead.getCategory(Alternative) is functionally equivalent and should be preferred over this one as it is clearer.

Specified by:

getCategories in interface IAssignmentsRead

Specified by:

getCategories in interface IAssignmentsToMultipleRead

Specified by:

getCategories in interface IOrderedAssignmentsToMultipleRead

Parameters:

alternative - not null.

Returns:

a set containing exactly one element, namely the category to which the given alternative is assigned, or null iff the alternative is not assigned. The returned set is immutable (if the assignment related to the given alternative later change, this change is not reflected to the object this method returns).