Enabling SOA Using WebSphere Messaging

Chapter 2. Product selection 31

infrastructure can be included in units of work that are coordinated by

WebSphere Application Server.

WebSphere MQ supports the concept of persistent and non-persistent

messages. Persistent messages are retained during system failures but provide

comparable low performance, while non-persistent messages provide high

performance but may be lost during system failures.

WebSphere MQ contains monitoring and accounting functionality. It provides

real-time performance information about flow of messages, it allows report

generation for queue manager usage on application level base, and it provides

facilities to identify the route that a messages took through a WebSphere MQ

infrastructure or interconnected WebSphere MQ infrastructures.

Administration of WebSphere MQ is typically done using control commands or

the WebSphere MQ Explorer administrative interface (Windows or Linux® only).

You can find more information about IBM WebSphere MQ at the WebSphere MQ

home page:

http://www.ibm.com/software/integration/wmq/

2.4 WebSphere ESB

WebSphere ESB is designed to provide an enterprise service bus for IT

environments built around open standards and SOA. It delivers easy-to-use

functionality built on the messaging and Web services technologies of

WebSphere Application Server.

The WebSphere ESB architectural model is shown in Figure 2-4 on page 32.

32 Enabling SOA Using WebSphere Messaging

Figure 2-4 Architectural model of WebSphere ESB

WebSphere Application Server is the foundation for WebSphere ESB, providing

not only the required quality of service, the J2EE runtime environment, and the

messaging engine, but also by providing broad support regarding open

standards and Web services. WebSphere ESB is built on the Network

Deployment package, providing a wide range of capabilities for large enterprise

networks, including clustering, failover, and scalability features.

On top of the infrastructure provided by WebSphere Application Server,

WebSphere ESB implements a mediation layer consisting of a mediation base

and mediation functions. The newly provided mediation framework is different

from the one implemented by WebSphere Application Server, as it is based on

the Service Component Architecture (SCA). It allows enhanced flexibility,

encapsulation, and reuse. Mediations implemented for WebSphere Application

Server can still be used together with WebSphere ESB, but the new tooling

provided for WebSphere ESB does not support the modification of these

mediations.

The mediation base is provided by SCA and Service Message Objects (SMO).

SCA supports the description of every mediation module through a

technology-neutral interface. SMO is based on SDO and supports the

representation of a binding-specific data format in a common, neutral way. The

application of this SCA/SMO-based programming model allows for the

configurable assembly of different mediation modules to a mediation flow, thus

enabling a very flexible and encapsulated solution.

Service Component

Architecture

Service Message

Objects

Mediation

Functions

Database

Lookup

Message Filter

and Router

Custom

Message

Logger

XSLT Message

Transformation

WebSphere Application Server (J2EE Runtime)

Mediation

Base