Michael Poulin wrote: > > > Ann wrote: "IBM has created a central notification system that ensures > that lots of applications that contain redundant capabilities are > notified of a changes that impacts all of them. If the system were truly > service orientated, it would no longer have redundant capabilities > implemented in all these applications. There would in fact be only one > system that maintains delivery date information." > > I disagree. If SOA reflects business model, then it has to accept > concurrent redundancy of the services. Does it make sense for an > individual enterprise - it is the business of the enterprise. However, > SOA solution should be capable of changing provider (and/or services) if > current one violates Service Contract and/or Service SLA. > > If an enterprise maintains only one service for a business functions, it > is not much different from an application: the service owner will be > able to dictate usability to the consumers and we will get the UK > 'service' model instead of US service model.
This is precisely where Jini excels. When using Jini, you would create a ServiceDiscoveryManager instance that utilized the appropriate ServiceTemplate for finding a notification service. You'd then be able to create a lookup cache, and just always ask that cache for the service. If there was no instance, you'd wait for any indicated timeout before failing. To keep one or more such notification services active, you might choose to use something like RIO to manage the SLA constraints and keep at least one running somewhere on a functional cybernode. Gregg Wonderly
