Legacy Issue Number: 6383
Source: Mercury Systems ( Jim Kulp)
Paragraph 2 of section 9.5.8 (of document ptc/03-10-01) is very confusing. While it is not normative, it is worth making clearer.
(Original defect identified by Kevin Richardson).
Composition associations in the model express that the class at the composite end owns and contains the class at the part end. In an XML file, the element that defines the class at the part end usually directly contains the definition for the class at the composite end. Since the default multiplicity on the near end of a composite association is one to one, the contained item cannot be legally contained in another element. It is possible to store it by itself in a separate file, though.
Proposed improved paragraph:
Composition associations in UML express that the class at the composite end (the containing class) owns and contains the class at the part end (the contained class). It is typical, in XML documents, for instances of contained classes to be embedded within the instance of the containing class. However, it is also possible to store contained instances by themselves in a separate file by using a proxy (using "href" or "xlink:href") to reference the contained instance in a separate file.
Since the multiplicity on the composite end of a composite association is always one to one in this specification, contained instances can only have a single such proxy reference.
Reported: DEPL 1.0b1 — Wed, 22 Oct 2003 04:00 GMT
Updated: Fri, 6 Mar 2015 20:58 GMT