Harm Smit wrote: > As the draft OASIS SOA Reference Model puts > it in its section "How is SOA different?": "To use an object, it must > first be instantiated, while one interacts with a service where it > exists". IOW, in SOA there is no notion of instantiation.
In the Jini platform, which is based on Java and uses the object system of Java, services are not instantiated. Instead, the interfaces to services are transfered as live objects to clients (when using RMI/JERI/JRMP invocation and endpoint implementations). These objects are unmarshalled on the client and the client is able to use the implementation of the interface as provided by the service. Because of mobile code, the actual implementation can run completely on the client, completely on one or more servers, or dynamically mix these two concepts. Would you assert that because of mobile code that RMI/JERI/JRMP invocation and endpoint implementations and that objects come into existance and go away that this can't possibly be a part of the implementation of an SOA? > Furthermore, it seems to me that quite some confusion stems from not > distinguishing between abstract services and the actual implementations > thereof, through the corresponding service providers. > > Taking your stock quote example, let's assume there is just one > universal abstract stock quote service. But that doesn't mean there is > just one universal stock quote service provider, and one may have very > good reasons to prefer one service provider over another, e.g., because > they don't cover the same range of stock symbols. > > Similarly, when invoking the services of a smart lightbulb, I'd need to > know whether it's the lightbulb in the kitchen or the one in the > bathroom. But both lightbulbs would implement the same abstract service, > even if they were from different vendors. This makes it sound like you would say that a Java interface is the service definition and that mobile code implementations are the instances for each appropriate resource. Gregg Wonderly ------------------------ Yahoo! Groups Sponsor --------------------~--> Something is new at Yahoo! Groups. Check out the enhanced email design. http://us.click.yahoo.com/SISQkA/gOaOAA/yQLSAA/NhFolB/TM --------------------------------------------------------------------~-> Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/service-orientated-architecture/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
