Re: ocl conformance test

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From: Laurence Tratt (
Date: Sun 15 Feb 2004 - 23:36:53 GMT

On Sun, Feb 15, 2004 at 09:57:17PM +0100, Stefan Haustein wrote:

Dear Stefan,

> I agree that support for XMI in tools is still far from perfect.
> However, most tools claim to be able to read XMI. Perhaps the availability
> of a vendor-neutral OCL conformance test file would encourage vendors to
> fix their XMI support---at least to a level that allows to read the test
> file. As you say, part of the problem is that there is no such test.

Tests are good as far as they go. However in practise they rarely cover all
that is needed. For that you really need to have a decent reference
implementation available. [For those of you unsure what I mean here: a
reference implementation can be defined as a (generally non-production
quality) freely available implementation which correctly implements all
mandatory parts of a standard and successfully executes all tests. It is
therefore available both as a demonstration of to how to implement a
standard, and also a way of testing interoperability between it and another
tool.] In the QVT world, the QVT-Partners - of which I am a member -
strongly advocated the concept of reference implementations as a way of
ensuring a higher quality end standard. Reference implementations have a
number of precedents outside the UML/OCL/QVT type world, and have been
highly successful at promoting real interoperability between tools
conforming to a standard. Without a reference implementation to back up the
suggested OCL tests, the cynic in me worries that conformance to the tests
will barely be worth the paper it is written upon.

To bring this back to XMI, the fact that most tools *claim* to be able read
XMI is nearly - but not quite - as laughable as the fact that some tools
have been claiming to support UML2 since even before it entered its current
stage of finalization. Marketing men aren't noted for their strict adherence
to the truth ;) Given that many (most?) tool vendors play little more than
lip service to OCL, I have to doubt whether an OCL test suite on its own
would encourage them in any way to improve their XMI support.

I do see a potential solution here to the XMI problem: a reference
implementation of XMI import/export would I think force vendors to improve
their own XMI support. I have heard vague whisperings that the OMG might
embark on such a course - I wouldn't hold your breath though!



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