So, while "directional" is perfectly valid, the term "unidrectional" may be a better an less ambiguous option. " These diagrams (.) may show navigability (by an open arrowhead) or nonnavigability (by an X) either always, only for unidirectional associations (oneWay), or never" (section B.3.2 about structure diagrams).Only shown for one-way navigable associations, this probably signifies bidirectional navigability" Nevertheless, in many places, the standard uses explicitely "unidirectional" and "bidrectional": " has no directional significance" (in section 20.1.4 about another kind of diagram)." Associations with navigability in both directions"." The arrow indicates that the Association is to be read as associating the end away from the direction of the arrow with the end to which the arrow is pointing" Le Service Interacadémique des Examens et des Concours (SIEC, académies de Créteil, Paris et Versailles) publie sur son site les sujets des concours internes et externes. The following wordings support the term "directional": If an end is not navigable, access from the other ends may or may notīe possible, and if it is, it might not be efficient. The precise mechanismīy which such efficient access is achieved is implementation specific. Instances at the other ends of the Association. (instances of an Association) can be accessed efficiently from Navigability means that instances participating in links at runtime The UML standard v2.5 from OMG defines in section 11.5.Associations the principle of navigability: Limited UML (Class, Use case, Activity, and Seq diagrams only). Does this means that "directional" is a bad choice and it would be preferable to replace "directional" by "unidirectional" ?Įdit: some additional elements about terminolgy for the records Object *parent // you can navigate back (Element knows about parent)Ĭhristophe is right. Sujet externe 2017, composition, bibliothèques. Sujet externe 2017, note de synthèse, sciences exactes et naturelles et les techniques. Sujet externe 2017, note de synthèse, sciences juridiques, politiques et économiques. Sujet externe 2017, note de synthèse, lettres et sciences humaines. Vector> element // ownnership by unique pointerīidirectional composition could then be something like: class Object Sujet interne 2017, étude de cas, bibliothèques. DoUML is a fork of the original Bouml editor by Bruno Pages that was born when Bouml's development abruptly came to a stop due to author's conflict with wikipedia administration. Vector element // own by value for example DoUML is a UML diagram editor capable of generating/reversing code in a multitude of programming languages (namely - C++, Java, Python, idl, Php). The unidirectional aggregation could therefore be for example: class Member // Elemetn doesn't know parent (=> unidirectional) For comparison, in MSVC2015 you find the notion of direction in the "Is Navigable" property of the association. This "directional" term refers hence to navigation possibility between the related objects. This kind of relation may considered to be a shortcut to define Generators will produce two attributes whose names are the roles's According to the wording used by the site of the BOUML UML toolbox, "directional" has to be understood as "unidirectional" (opposed to "bidirectional") :Īggregation : to define a bi-directional aggregation, the code
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