1Z0-451: Working with Mediator Components

This is part of 1Z0-451: Oracle SOA Foundation Practitioner Exam

* See here.

* Provides a lightweight framework to mediate between various components within a composite application.
* Converts data to facilitate communication between different interfaces exposed by different components that are wired to build a SOA composite application.

* Content-Based and Header-Based Routing
* Synchronous and Asynchronous Interactions
* Sequential and Parallel Routing of Messages
* Transformations
* Validations: using Schematron or an XSD file.
* Java Callouts
* Event Handling
– supports subscribing to business events and raising business events.
* Dynamic Routing
– via business rules.
– outbound services can be called only over SOAP.
– No assignment, transformation, or validation can be performed.
– not possible for Oracle Mediators with a synchronous or one-way interface.
* Error Handling, supports both
– manual error handling
– fault policy
* Echo
– echoing source messages back to the initial caller after any transformations, validations, assignments, or sequencing operations are performed.
* Multiple Part Messages

* See here.

* Business events do not care about client subscribers:
– Typically one-way, fire-and-forget, and asynchronous.
– Do not care if there are receivers.
– Do not care where receivers are and what they do with the data.
– Do not wait for receivers to complete.
* Use invocation if there is dependency on event receivers.
* A business event is defined using the event definition language (EDL) which contains:
– Global name: typically a Java package name.
– Payload definition: mostly XSD.
– Example:

<?xml version = '1.0' encoding = 'UTF-8'?>
<definitions targetNamespace="/model/events/edl/BugReport"
 xmlns:ns0="/model/events/schema/BugReport"
 xmlns="http://schemas.oracle.com/events/edl">
   <schema-import namespace="/model/events/schema/BugReport"
 location="BugReport.xsd"/>
 
   <event-definition name="bugCreated">
      <content element="ns0:bugCreatedInfo"/>
   </event-definition>
 
   <event-definition name="bugUpdated">
      <content element="ns0:bugUpdatedInfo"/>
   </event-definition>
</definitions>

* Business events are deployed to the metadata service (MDS) repository.
– EDL publishing: deploying a business event to MDS along with its artifacts such as XSDs.
– EDL can not be unpublished.
* Business events are published in the Event Delivery Network (EDN).
– The EDN runs within every SOA instance.
– Raised events are delivered by EDN to the subscribing service components.
* Mediator and BPEL service components can subscribe to and publish events.
* EDN has two different implementations:
– EDN-DB (preferred): uses an Oracle database as a back-end store.
– EDN-JMS: use a generic JMS queue as a back-end store.

* Local event connection.
– Used if receiver resides on the same WebLogic Server.
– Synchronous subscriptions are executed synchronously.
* Remote event connection.
– Used if receiver resides on a different container (different JVM).
– Only supports asynchronous subscriptions.

Next>> Human Workflow

* Getting Started with Oracle Mediator