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Figure 10.24 As this server error demonstrates, SCA's WSDL binding only works well for services whose
interfaces are restricted to using primitive types.
The difficulty comes when you try to implement a FoodAdapter. By necessity, it will
depend on a FoodImpl implementation class, which leaves the SpecialOffer
interface with a dependency on an implementation class. If you're getting into the
OSG i spirit of things, this should leave you feeling like you haven't brushed your
teeth in a week.
A much more OSG i-centric solution to the problem is to wrapper the complex
SpecialOffer service with a simpler PrimitiveOffer service for the purpose of distri-
bution. A Blueprint reference listener can be used to track PrimitiveOffer services.
The listener would automatically detect and consume each bound PrimitiveOffer
service, and use it to generate and register a wrapper SpecialOffer service. But this
significantly increases the complexity of using SCA for service remoting.
Does this mean you shouldn't use SCA for remoting your OSG i services? Not neces-
sarily. Although we haven't provided a detailed example, SCA does provide support for
distributed transactions, which may be critical to your application. Furthermore, as
you'll see in chapter 11, SCA offers a lot more than remote services. You may find SCA
remote services fit neatly into a broader SCA -based architecture. If your application
server includes SCA , you can bypass the hand-assembly of your stack that we described
earlier. And if your service interfaces are already based around primitives and Strings,
you won't need to worry about rewriting services to avoid the use of complex types.
Remoting is generally considered to be one of the more difficult parts of enterprise
programming. We hope that you can now see how the intrinsic dynamism and modu-
larity of an OSG i framework dramatically simplifies this situation. Not only does OSG i
lend itself to a remote model, but it also provides simple, easily reusable remoting
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