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<div class="moz-cite-prefix">Dear Conrad,<br>
<br>
in response to your comments, Alexander Knapp writes:<br>
<br>
<p class="MsoNormal"><span>Thanks for the comments.</span></p>
<p class="MsoNormal"><span lang="EN-GB">“Not sure I'm reading this
correctly, but it seems to say the properties involved in a
composition association are properties of m, whereas they are
usually properties of the classes at the ends of the
association.”: It is not intended to express ownership here.</span></p>
<p class="MsoNormal"><span lang="EN-GB">“Properties can be
composed without being member ends of an association. The UML
2.5 spec describes aggregation in the Property subclause
(9.5.3), without constraining the properties to be member ends
of associations. The phrase quoted here describes a composite
property with ("grouping its") values. Feel free to ask Ed
and others, this is well known to be the interpretation of the
spec, and is implemented in tools.”: Yes, indeed, a property
itself could be composite without being a member end of an
association. I only now get the semantics of such a
declaration, say, c.p : \tau’[c’] with p composite (if I
understand correctly): it would be that if o is an instance of
c, and o.p are the values for property p, these values are
parts of o (and, hence, deleted if o is deleted – which we do
not discuss); each such value can only be contained (as a
part) in a single object. Currently, we only discuss the case
where a composite property is a member end of an association,
but with this clarification we could also handle the
“non-member end” case by adding to the definition of
“attributes” that p may also be decorated by a filled lozenge
and adding the ownership semantics. In any case, the text
starting with “In UML, each Property may have AggregationKind
composite” should either clarify that we only discuss the
“member end” case or could be skipped altogether. (The quote
with “grouping its” is now on page 110 of the UML 2.5
specification, the constraint for member ends of binary
association on page 218.)</span></p>
<span lang="EN-GB"><br>
<br>
All the best,<br>
Till<br>
<br>
</span>Am 08.10.2015 um 17:27 schrieb Bock, Conrad:<br>
</div>
<blockquote
cite="mid:DM2PR09MB0543DBD96AA0FBEA07D9A9B094350@DM2PR09MB0543.namprd09.prod.outlook.com"
type="cite">
<pre wrap="">Till et al,
Took a quick look and the interpretation of composition is
still wrong, see attached. Apologies for not having looked
at this earlier. Will review more carefully for the Oct 15
deadline.
Conrad
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