Bob.Cowdery at Bob.Cowdery at
Wed Dec 22 14:48:02 CET 2004

I am trying to build a capability based API. That is, an instance of the api
will reflect the capabilities of some underlying services. I could have
several different instances of the api concurrently running against
different back end services. A ui applet will bind to an api instance. I
want to make this easy to use from the ui perspective so I envisage exposing
a number of properties as the variable part can be represented by
properties. I want a property to exist only if a capability is available so
it is easily tested. I have tried using Property and Metaclasses to do this
and although both work I can't figure out how to make multiple different
instances as both get executed on 'import' and thus only one instance can be
created. Inside the metaclass I have to get hold of the capability map I
want to build the instance against. The only way I can see to do this at the
moment is to have a metaclass for each capability type and hardcode the type
inside it, then pick the appropriate metaclass when I build the
implementation class.
Bob Cowdery
CGI Senior Technical Architect
+44(0)1438 791517
Mobile: +44(0)7771 532138
bob.cowdery at <mailto:bob.cowdery at> 

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