Isolating Services

As you begin to define a service-oriented application:

• Review the overall requirements, as well as those of each service.

• Identify which of the company's systems offer the functionality of interest.

• Consider accessing traditional application by way of adapters, so you can embrace a service orientation with less expense.

• Create a context diagram as a visual summary of the project's boundaries and relationships.

Figure 3.2 shows a context diagram for the Highlight Insurance project.

Figure 3.2: Context diagram for the Highlight Insurance project

At the center of any context diagram is the functionality being developed. The center represents a functional boundary. By defining such a boundary, you define the responsibility of the development group and of the surrounding groups, which are organizations that control the software that will interact with the new applications.

At Highlight Insurance, the new applications support customers, underwriters, and agents. The development group that handles the new service-oriented applications:

• needs the technical manager of each of the surrounding groups to help plan software interfaces.

• needs access to a customer's previous quote.

• needs services that determine whether to issue a new quote and whether underwriter intervention is required.

• needs services to send confirmation email as well as to print confirmation letters for subsequent mailing

• needs to inform the accounting department of purchased policies, to allow billing.

• needs to give the underwriter a way to verify credit checks and DMV information.