Additional SOA Patterns –Supporting Composition Controllers - Applied SOA Patterns on the Oracle Platform - page 543

Initial analysis
Traditionally, we will start with the analysis in a vendor-agnostic way, and we would like to
repeat the basic things here again just to summarize the facts from previous examples and
clarify the EDN-SOA hierarchy. Please get back to our SOA metadata taxonomy that is
visualized in the Managing Service Repository section in Chapter 5 , Maintaining the Core -
the Service Repository . An event is the next thing that follows an object, indicating the ob-
ject's change of state. That's it! It's not just some faceless and abstract "occurrence on the
input receptor", as someone may describe it. Sorry, but occurrence of what? The event has
always happened on (or around) something solid, and when it happens, object(s) can be
serialized in their transportable form: a message. It is not always required though, and we
will describe when it will be.
In the Event Processing documentation ( http://docs.oracle.com/cd/E28280_01/doc.1111/
e14476/overview.htm ), Oracle provides examples of possible events, including the follow-
ing:
• Communication events : These are based on the fact of message/transport contain-
er reception. The object is a transport container.
• Machine events : Usually (in Oracle realization), these are handled by Java-em-
bedded devices; some on ME for small devices without complete Java support
(pacemakers or microwave microcontrollers, for instance); some on SE, such as
the ones installed on high-speed communication gateways in datacenters that
handle service edges; and some on communication events mentioned in the preced-
ing point. For telecom, a good example of such events would be booting/starting
STBs or cable modems with the TR-69 device management protocol's support
when devices' changes of state are emitted to the auto communication server
(ACS) . It is obvious that in this case, the object is a device itself.
• Security events : These are derived from the preceding points and are an object's
AA request to change its privilege status ( I want to invoke... I want
to participate ); these are usually detected on the Service Gateway's edge.
Equally, all other objects' alterations related to all security patterns from Chapter 7 ,
Gotcha! Implementing Security Layers , can be included in this event type.
• Environmental events : These include infrastructural events such as WLS node
up/down and basic environments such as temperature/pressure shift and so on.
• Business logic events : Generally, all events are associated with business objects'
change of state in our entity services.