In other words, commit the design to high-level reusability
aspects of service-oriented assets, while insuring that the underpinning service implementation
complies with asset reuse best practices. The following reusability guiding principles can assist
with the establishment of an efficient logical design composition strategy:
??? The logical design composition diagram should focus on solving a problem rather than
providing comprehensive solutions to numerous organizational concerns.
??? Always find opportunities to engage existing services in a solution rather than constructing
new ones.4 Therefore your design process should first examine the service-oriented
software portfolio of the organization to find reuse opportunities.
272 Ch. 13 Service-Oriented Logical Design Composition
??? In the logical design solution, choose the closest route to linking services, and avoid
unnecessary round trips or involvement of assets that hardly contribute to solving a
problem. This calls for reevaluation of proxies, security barriers, employment of intermediaries,
and utilization of gateways.
??? Use coarse-grained services as much as possible, and avoid excessive message exchange
with remote fine-grained services.
??? Avoid unwarranted use of intermediate service brokers. Collapse an expanded design to
eliminate unnecessary hubs. Remember, the shortest route between collaborating services
is always preferred.
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