NETTING IT OUT

In the previous four reports, we explained how Service-Oriented Architecture (SOA) can be applied to update and extend operational applications so that your existing systems can be retooled to meet current and future customer needs. This report addresses the design and implementation of new applications using SOA.

New applications often use services developed in the process of retrofitting existing operational systems, but new applications offer greater opportunities to rethink how your business operates and how it is presented to customers, suppliers, and employees. Indeed, if you approach developing services-based applications as an exercise in composition rather than creation, you will find many opportunities to reuse existing services or to share the effort required to develop key services among multiple application development projects.

This report works through a case study to show how new applications can be composed from services. We extend the case study that started in our earlier reports on service granularity and show how a variety of basic as well as innovative applications can build upon a shared set of business, application, and technology services.

CONTEXT

In prior reports, we outlined two taxonomies for classifying and defining services of appropriate granularity. One classifies services as:

- • Business services
- • Application services
•-  Technology services

The other taxonomy categorizes services as:

-  Base services
- • Composite services

When these taxonomies are used together, their intersection defines six “buckets” into which candidate services are sorted. (please download article to see Table A.) This separation of concerns clarifies the role of each service and helps to ensure properly defined services within an overall services-oriented architecture.

Base business services are essential tools of data and application integration. These services enable you to capture or reconstruct the data, business rules, and processing associated with fundamental business concepts such as customer and product. Base business services form the foundation for retrofitting and for repurposing existing application functionality...

*** endnotes ***
1 See “Granularity Rocks: Getting Services’ Granularity Right,” July 17, 2003, http://www.customers.com/articles/Granularity-Rocks
2 See “Retrofitting Applications with Service-Oriented Architectures,” October 10, 2003, http://www.customers.com/articles/retrofitting-applications-with-service-oriented-architectures-strategies/