Guideline: Identify Service Interfaces from Collaboration Role Interaction Patterns presents four rules for describing ServiceInterfaces, based upon pairs of interacting roles in
service collaborations. The rule illustrated here is:
Rule 3: Create either a simple UML interface or a ServiceInterface with only a provided
interface when all consumer-provider communication uses a "request-response" collaboration
pattern.
In Figure 1, we have a consumer, "role1," and a provider, "role2." They communicate by using a simple request-response
collaboration pattern. For example, "role1" calls operations that are provided by "role2," and "role2" responds by
using conventional operation returns. Here, there is no complex interaction protocol between the service consumer and
the service provider.
From the perspective of the provider, we have discovered either a simple UML interface or a ServiceInterface
with a single provided interface. In this instance, we have rendered this as a ServiceInterface with a single
provided (realized) interface. This is shown in Figure 2.
Figure 1. Interaction pattern that yields a simple service interface
Figure 2. Static model of the simple service interface
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