Patterns: Extended Enterprise SOA and Web Services

Chapter 11. Exposed Direct Connection runtime pattern: SOA profile 239

Successfully implementing an SOA requires applications and infrastructure that

can support the SOA principles. In the previous chapter, we SOA-enabled the

applications by exposing the business functions as services. Now in its quest to

build a comprehensive SOA solution, ITSO Good wants to build a basic SOA

infrastructure that addresses the following requirements:

򐂰 Build an SOA infrastructure that provides the ability to integrate and manage

the Retail, Warehouse, and other new services that are expected to be

exposed within the enterprise.

򐂰 To provide access to external services of the Manufacturing partner systems

in a controlled and secured manner. This will provide ITSO Good a single

point of control to implement and manage its corporate security policy with

regards to accessing partner systems.

11.2 Design guidelines

This section analyzes the infrastructure requirements described in the business

scenario. It uses the Patterns for e-business to select the appropriate runtime

pattern and also discusses the various architectural decisions involved in

implementing the solution.

11.2.1 Analyze IT infrastructure requirements

ITSO Good requires a middleware component that can support its SOA

infrastructure requirements. So, what are these requirements for an SOA

infrastructure?

This has been the subject of much debate among the different vendors in the

SOA marketplace, often for competitive reasons. Taking a neutral and

customer-centric view, we look at some of the basic and commonly agreed upon

aspects of an SOA infrastructure.

SOA infrastructure requirements

The goal of ITSO Good is to build a flexible and durable infrastructure that makes

it easy to integrate the business aligned services created in an SOA.

The basic requirements for a service oriented infrastructure are:

Service in an SOA environment: A service represents a reusable business

function that is defined by explicit implementation-independent interfaces,

loosely bound and is invoked through communication protocols that stress

location transparency and interoperability.

240 Patterns: Extended Enterprise SOA and Web Services

򐂰 Distributed is the ability to integrate services that are distributed across the

enterprise and even beyond in the extended enterprise comprising partners

and suppliers.

򐂰

Flexibility/Interoperability enable interaction through services that are

defined by explicit implementation-independent interfaces and are loosely

coupled.

򐂰

Communication provides support for communication protocols that stress

location transparency and interoperability.

򐂰

Integration provides the ability to integrate services seamlessly across the

heterogeneous systems and also provide support for other integration

paradigms in the SOA ecosystem like message-driven and event-driven

based integration.

򐂰

Mediation services support service routing and substitution, protocol and

message transformations, and other message processing services.

򐂰

Quality of service includes security, transactionality, and availability.

򐂰

Leverage existing IT investments supports both service-enabled applications,

such as Web services enabled, as well as existing applications based on

traditional Enterprise Application Integration (EAI) standards and

technologies, while providing a consistent service model.

򐂰

Management provides a central point for managing and monitoring the

deployed services and also to provide the ability to integrate with systems

management tools.

The infrastructure requirements above are implemented as services themselves,

as

Infrastructure Services. And more importantly these services need to be

nonintrusive to the business aligned services.

Relevant infrastructure requirements

The infrastructure requirements that are relevant to the given scenario are:

򐂰

Distributed is the ability to integrate the Retail and Warehouse services that

are distributed across the enterprise to the Manufacturing services of the

external partner systems.

Note: The requirements listed here are not exhaustive in nature. We have only

thrown light upon some of the basic features of an SOA infrastructure in this

chapter. There are also other aspects such as Autonomic capabilities and

Infrastructure Intelligence, which are provided in some of the products

available in the market today.