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22.02.05
Tim Ewald on (Indigo) contracts
Why is it Tim Ewald expresses my thoughts so much better than I do ;-) ?
Here is what Tim Ewald says about tool support und why simply relying on tools to generate your contract is not enough:
“The problem today, as I see it, is that tools aren’t actually very good at that, as evidenced by the problems people have getting their tools to emit contracts that actually express their desires and that their clients can consume. The reality today is that if you care about your client being able to EASILY consume your service, independent of toolkit or platform, you have to care about your contact. If you author it indirectly using source code, you need to not only know how XSD and WSDL work, but how your tool maps to them as well.”
His thoughts about WSDL/XML/XSD contracts concerning loose coupling pretty much summarize what I’ve been trying to get across:
“There is another orthogonal aspect to this as well. Real loose-coupling between services will come when people actually leverage the composibility and open content model aspects of XML. If you start from OO code to generate your contract, you are unlikely to do that. How many loosely-coupled OO models have you seen? Translating them to XSD won’t give you loose-coupling, it will give you tight-coupling in another language.”
OO simply isn’t SOA. You may use OO languages to implement a SOA but you have to adhere to the message/document-based paradigm!
Posted by Hartmut Wilms at 22.02.05 21:02