RE: java annotations & the semantic web

In terms of representing intensional classes, yes. But such mechanisms do not easily allow extensional classes, which means you can't use them for classification of data, inference, etc, and so you can end up with a system based on the least common denominator of the two.

>     - functional: if A rel B and A rel C the A == C
Typo?

> Using URIs for beans is a lot better than using table names. URIs are *Universal*.

Most OO design tools have used some form of UUID for ages. Flexible ORM schemas use a lookup layer.

A lot of what went into EJB3 is based on improving productivity for sort lifecycle and lifetime systems - if your business rules are changing weekly, you don't need an ID that will outlast the sun.

> The above now maps very easily into UML class diagrams (which are just another notation for OWL)

Be very careful that the implementation specific semantics are the same.

> In the above I have only annotated the setter method. One could also 
> annotate the getter, adder, getAll methods or even a field.
> This ends up creating too many places for annotations
> I think. Is there a standard solution for this?

For classes, annotating the field and auto-generating the accessor methods is fairly standard.

For interfaces, fields are static so your example probably doesn't mean quite what you intend it to, and has the side-effect of exposing superfulous static fields in the interface.

I'd probably generate the interface from the OWL or from the class rather than trying to go the other way round.

> it seems clear to me that setters and getters don't give us quite 
all that we want. It would be really nice if java beans also had addXXX 
and getAllXXX.

The beans specification uses array returns for multidimensional values, though this is somewhat clunky.

The JMI (Java Metamdata Interface) codifies a richer set of accessors for reflection, though it is out of data with respect to the UML standard it is based on, nor likely to get updated soon due to the fragmentation of the UML community.  The eclipse EMF project is more current, and has some interesting modelling and code-generation tools, but not standardized with Sun, and based on 1.4 so is annotation free.


Pete

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Received on Thursday, 25 August 2005 09:23:46 UTC