Introducing Service-Oriented Architecture

In today's world, implementing distributed systems that provide business value in a reliable fashion presents many challenges. We take many features for granted when developing nondistributed systems that can become issues when working with disparate distributed systems. Although some of thesechallenges are obvious (such as a loss of connectivity leading to data being lost or corrupted), for other aspects such as tightly coupled systems thedependencies between the various components of a system make it cost prohibitive to make changes as needed to meet the demands of the business.

Business processes quite often are supported by systems that are running on different platforms and technologies both within and outside the organization. Service-Oriented Architecture (SOA) is a mechanism that enables organizations to facilitate communication between the systems running on multiple platforms. This chapter introduces the fundamental concepts of SOA. The objective of this chapter is to discuss the following:

• What does SOA mean? How do you use messages, which act as the cornerstone for SOA implementations, to facilitate SOA?

• What makes SOA the preferred approach to design complex heterogeneous IT systems? Are web services the same as SOA?

• What are the four tenets of SOA?

• What are the implementation building blocks of SOA?

• How do you utilize all these building blocks to send messages between loosely coupled services?