Data Model for Quantity v0.5 - inheritance vs aggregation
brian.thomas at gsfc.nasa.gov
Mon May 10 13:56:42 PDT 2004
On Monday 10 May 2004 04:10 pm, Patrick Dowler wrote:
> FYI - realization is the relationship between an interface and the class that
> implements it. One interface still inherits from another. the Q document does
> specify an inheritance relationship.
Yes, I agree. I was sloppy in my description. Nevertheless, the intention
is correct, we shouldn't see aggregation lines in the diagram, just 3 or 4
interfaces inheriting from one another in direct succession.
> [snip description of how this inheritance relationship between interfaces
winds up forcing one-to-one implementation anyways]
> The interfaces in the Q doc specify a type of relationship that the
> implementations are more or less forced to follow.
> Interfaces are meant to be declarative ("I have these methods!") first and
> can - if it is valuable - have an interface heirarchy. Here we have both
> and it is an extra burden and limitation on implementors.
What is your solution then? Have you been running into problems
implementing these interfaces?
* Dr. Brian Thomas
* Dept of Astronomy/University of Maryland-College Park
* Code 630.1/Goddard Space Flight Center-NASA
* fax: (301) 286-1775
* phone: (301) 286-6128 [GSFC]
(301) 405-2312 [UMD]
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