Friday, June 18, 2004

Compatibility in a temporally decoupled distributed world

Carlos comments on the one-sided nature of Liskov's Substitition Principle.
As I've said many times, in a document-centric, message-centric world, objects are not the center of the universe so API substitutability is not a useful metric for compatibility. (Example, in REST, there is only one "API" so substitutability does not arise).

I think Carlos is right when he says we need to look at both the "provider" and "requirer" sides. We need to focus on foreward and backward compatability of message *notations* by means of a message processing model, not API comptability through polymorphism.

RIG 6 in the interoperability guidelines I am working on with the Irish government for the public services broker, addresses this issue.

Dave Orchard is well worth reading on this topic.
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3 comments:

  1. Anonymous8:57 AM

    Thanks for sharing the link, but unfortunately it seems to be offline... Does anybody have a mirror or another source? Please reply to my post if you do!

    I would appreciate if a staff member here at seanmcgrath.blogspot.com could post it.

    Thanks,
    Thomas

    ReplyDelete
  2. Anonymous7:51 AM

    Hello,

    Thanks for sharing this link - but unfortunately it seems to be down? Does anybody here at seanmcgrath.blogspot.com have a mirror or another source?


    Thanks,
    William

    ReplyDelete
  3. Sean McGrath8:05 AM

    Best to contact support@reachservices.ie for RIG documents.

    Sean

    ReplyDelete

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