Patterns: Implementing Self-Service in an SOA Environment

Chapter 10. Web services scenario 323

10.6 Creating the mediations

Mediations are implemented as mediation handlers. A mediation handler can be

deployed, and each mediation handler executes some specific message

processing at runtime (for example, transforming a message format or routing a

message to a particular destination). A

mediation handler is a Java program

framework to which you add the code that performs the mediation function.

This section illustrates creation of two mediation applications:

1. A router mediation will receive messages at the destination created for the

HomeDelivery outbound service. It will check the delivery type parameter

send by client (Home, Business, or All) and based on the value it will send the

message to the HomeDelivery outbound service, the BusinessDelivery

outbound service or to both. If All is selected, the reverse routing path is

changed to a queue that will be mediated with the aggregator mediation.

2. A mediation will aggregate responses from multiple services into one

response. This situation will occur when a user elects to get both a home and

a business account (All). This mediation will be attached to a queue

destination that receives the responses from both the BusinessDelivery and

HomeDelivery services.

Figure 10-28 Mediation flow

HomeDelivery EJB

BusinessDelivery EJB

HomeDelivery EJB

HomeDelivery EJB

DeliverySystem EAR

HomeDelivery EJB

ClientDelivery EJB

HomeDelivery EJB

HomeDelivery Proxy

Processor.ear

HomeDelivery EJB

RoutingMediationsEJB

HomeDelivery EJB

Aggregator EJB

Service ingration bus

HomeDelivery

Inbound service

BusinessDelivery

outbound service

HomeDelivery

outbound service

If type="All"

If type="Home"

If type="Business"

If type="All"

DeliveryReponseDestination

DeliveryRequestMediation

DeliveryReponseMediation

TempDestination