Patterns: Implementing Self-Service in an SOA Environment

236 Patterns: Implementing Self-Service in an SOA Environment

3.1.3.1.1) A response page is sent to the customer stating that the registration

process is underway and he will receive an email confirmation when

it is done.

3.1.3.1.2) The message placed on a JMS queue is retrieved by a message

driven bean, initiating a serial process. The process invokes the

back-end services.

3.1.3.1.4) Using the primary key in the message, the customer data is retrieved

from the local database.

3.1.3.1.6) The customer data is sent to the Credit Service to get a quote. The

Credit Service is available as a Web service and is accessed through

the ESB (enterprise service bus).

alt-a) If the customer rating is acceptable, the customer data is stored in

the existing CRM on CICS using JCA connectors. The CRM

maintains the master copy of customer information. Each business

application that corresponds to the customer type selected will be

sent the information and will return an account number. Once the

account numbers are returned, an e-mail is sent to the customer

indicating the registration was accepted and the account numbers

assigned.

alt-b) If the rating is not acceptable, the customer data is removed from the

database and an e-mail is sent to the customer indicating the

registration was rejected.

8.3.3 Technology and product selection

The application designers decided on the technology to use based on the

existing back-end applications and the requirements of the new application.

WebSphere Application Server was determined to be the best choice for the new

application because it is a simple, service-oriented J2EE application design

provided the functionality needed, while facilitating additions to the application as

the business grows.

The user interface is implemented as one application while the driver for the

registration process is implemented as a separate application. Future processes,

such as an order process, can be implemented without affecting existing process

applications. Simple changes to the user interface application can accommodate

the new process. The processes required are invoked by placing a message on

a queue to be picked up by a message-driven bean that starts the process.

Using a Web service interface to access the credit check service allows them to

easily change credit check providers.

Chapter 8. Business scenario and design 237

A Web service interface also works well for their home and business delivery

services. Adding additional options, such as institutional delivery, are simplified

by using a standard interface.

Their current preferred e-mail provider is accessed through a J2EE application

that uses a messaging interface. The messaging infrastructure provides reliable,

secure delivery of messages.

Their existing application that maintains the customer registration data is a CICS

application. Wrapping the existing application as a Web service allowed them to

build the new application without worrying that future alterations would be

needed to accommodate changes in the CICS application.

The service integration technology in WebSphere Application Server was chosed

for the implementation of the enterprise service bus. It provides transport

capability for Web services, the default messaging provider, and its mediation

capability is used to implement the router and decomposition aspects.

238 Patterns: Implementing Self-Service in an SOA Environment