Additional SOA Patterns –Supporting Composition Controllers - Applied SOA Patterns on the Oracle Platform - page 546

vanced Structural Rules Language (SRL) and an enhanced concept of data patterns is in
fact a combination of RE, Workflow Engine (so-called RuleFlow), and EDN. Although
this product is brilliant, we cannot describe this concept as very flexible because several
SOA principles are not really supported. If the nature of your events and their object
sources is broader than just the calculation of taxes/pensions, please consider separating
EDN layers and agent groups.
Event consolidation, filtering, and aggregation serve the following two main purposes:
• Identification of the business (complex or compound) event from a series of time-
or correlation-related basic events
• Recognition of consumers' event subscribers of these business event(s)
Needless to say, event message delivery must be strongly conducted to Idempotent
Activity settings for Partner Link (if you are using BPEL). It not only affects the per-
formance (when set to false), but can also be undesirable from the business perspective
(resending the same notification twice if set to true by default after restarting the faulty
process.) In any case, resending the same notification is not a good idea. We will return to
the application of reliable messaging in EDN a bit later; now, it would be prudent to
demonstrate the handling of temporal and business-correlated basic events, and their ag-
gregation and recognition as a compound business event using RE. As a theoretical back-
ground, we will refer to the classic publication Formal Semantics For Composite Tempor-
al Events in Active DBS , Iakovos Motakis , Carlo Zaniolo , UCLA/Cambridge Technology
Partners Publication . This publication introduced the Event Pattern Language (EPL).
Processing Object Context in business logic events
For practical purposes, we would like to revisit the logistic example we demonstrated
earlier, now with the example of a shipping company.
The shipping company has a number of vessels, transporting cargo on various routes with
multiple port calls. (Again, how many objects have we just listed here? Count carefully.)
Port calls could have several different purposes such as loading, unloading, bunkering,
maintenance, and so on (quite often combined). Some customers (cargo owners) would
like to be informed only about schedules for certain routes with certain port call types in
selected ports, performed by certain types of vessels. Business reasons could be different,
and some of them are as follows:
• A customer is looking for the shortest delivery time, without any transshipment