Applied SOA: Service-Oriented Architecture and Design Strategies

CHAPTER 10

Designing and Using Integration in SOA Solutions

Existing software assets are essential to your business. Application systems contain a reservoir of business rules vital to operational continuity, yet remain undocumented outside the source code. These software assets and the accompanying business data are difficult to decipher and almost impossible to replicate using “green-field” approaches.

– William Ulrich

With all the advances in SOA that provide the best hope for efficient, flexible, and cost-effective implementations, the bulk of the business processing today is still carried out by legacy systems and packaged applications, like Enterprise Resource Planning (ERP), Customer Relationship Management (CRM), and so on. If there is a big bang conversion from existing applications to new systems, architecture will not work. Instead, IT organizations should bridge the gap via a carefully planned transition and migration process. This means that SOA solutions cannot be built in a vacuum — the only cost-effective approach is to base new solutions on the existing application portfolio and leverage integration as a mechanism for accessing the existing capabilities. But, it is not as simple as just Web-Service-enabling existing applications and data. Instead, the existing functions and data need to be transformed into new capabilities and information that can move the enterprise forward toward its current goals and strategies, and not keep it tied to the 20-year-old strategies ...