Remember,
atomic services are not the chief challenge here. Interaction between composite services and
service clusters can introduce a greater concern because they not only must interact with external
services and consumers, but they are also required to propagate messages to their internal
constituents.
Therefore, consider the following guiding questions that should be asked when devising
a service relationship: ???What is the method that should be employed to propagate messages to a
hierarchical structure that is typical of composite services???? ???How can cluster??™s internal services
communicate with remote consumers???? ???Can an external service communicate directly with an
internal service that is a part of a composite service????
A FORMAL SERVICE LOGICAL RELATIONSHIP NOTATION
Before discussing the fundamentals of a service-oriented design relationship, it is time to introduce
a simple logical relationship notation. This contains four connectors that make it possible to
convey an apparent or implied relationship between service-oriented software assets, such as
services, peer services, and even consumers, and explain their fundamental links. It is important
to recall that these symbols are used to illustrate the message paths of exchanged data and
information over a network.
The general form of a service relationship connector is a line that indicates direction and
identifies the visibility of services, as depicted in Exhibit 12.
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