In the
Unified Modeling Language
The Unified Modeling Language (UML) is a general-purpose, developmental modeling language in the field of software engineering that is intended to provide a standard way to visualize the design of a system.
The creation of UML was originally m ...
(UML), an Element is an abstract class with no superclass.
[OMG Unified Modeling Language, Superstructure, Version 2.4.1] It is used as the superclass or base class, as known by object oriented programmers, for all the metaclasses in the UML infrastructure library. All other elements in the UML inherit, directly or indirectly from Element. An Element has a derived composition association to itself to support the general capability for elements to own other elements. As such, it has no additional attributes as part of its specification.
Associations
An association describes a set of
tuple
In mathematics, a tuple is a finite ordered list (sequence) of elements. An -tuple is a sequence (or ordered list) of elements, where is a non-negative integer. There is only one 0-tuple, referred to as ''the empty tuple''. An -tuple is defi ...
s of typed instances.
[UML 2 Certification Guide, Tim Weilkiens and Bernd Oestereich - ]
*''ownedComment: Comment
': An Element may own, or have associated to it, an arbitrary quantity of comments.
A comment is sometimes referred to as a note.
The asterisk in brackets is the Comment's
multiplicity
Multiplicity may refer to: In science and the humanities
* Multiplicity (mathematics), the number of times an element is repeated in a multiset
* Multiplicity (philosophy), a philosophical concept
* Multiplicity (psychology), having or using mult ...
which means that there can be an arbitrary number of comments owned by an Element.
*''/ ownedElement: Element
': An Element may own an arbitrary quantity of elements.
This is called a derived union, symbolized by the forward slash notation. The asterisk in brackets is the Element's
multiplicity
Multiplicity may refer to: In science and the humanities
* Multiplicity (mathematics), the number of times an element is repeated in a multiset
* Multiplicity (philosophy), a philosophical concept
* Multiplicity (psychology), having or using mult ...
which means that there can be an arbitrary number of elements owned by an Element.
*''/ owner: Element
..1': The Element that owns this element.
This is called a derived union, symbolized by the forward slash notation. The
..1is the owning Element's
multiplicity
Multiplicity may refer to: In science and the humanities
* Multiplicity (mathematics), the number of times an element is repeated in a multiset
* Multiplicity (philosophy), a philosophical concept
* Multiplicity (psychology), having or using mult ...
which means that there can only be zero to one owner element.
The Element class belongs to the base package in the UML called the Kernel. This is the package that contains the superclasses that make up the superstructure of the UML.
Subclasses of Element provide semantics appropriate to the concept they represent. The comments for an Element add no semantics but may represent information useful to the reader of the model.
Notes
Updated for the UML version 2.4.1
References
Further reading
External links
Documents associated with Unified Modeling Language (UML), v2.4.1
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Unified Modeling Language