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2005-01-14

Comments

Johan N2

"... "Implementation-First" ... You first write your components and from these the underlying platform produces the contracts for you. This is the easy, but erroneous, way to go."

I don't agree here, Contract-First absolutely, but the contract have nothing to do with the "implementation-first" it has to do with the model (analyze, Design)-first. You never start building a solution if you don't have the design ready, and the contract will be an important specification for the design. The contract is also designed against the consumer at the first. Then when this contract is defined and the consumer thinks its ok you start building the service.

And this approach is general for all development processes. Or have I missed something?

I never start coding the domain if I don't have any specification, and for SOA you can’t have any specification if you don’t have the contract right?

As Pat Hallend put it when I talked with him "the messaging interface (contract) becomes the specification for the individual application (service)."

Please correct me if I'm wrong or have missed understood all this.

Best,
Johan

Dag

I agree with you that in the analyze and design phase it is allways contract-first. But what I talk about is the next phase, the implementation phase. It that phase you could either choose to start writing the code that implement the contract in VB or C# that you have designed before (implementation-first) or you could start designing the interface in WSDL and XSD first.

The question is more how you go from the design phase where your components are designed and described in a design document to the implementation phase.

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