Migration of a Chosen Architectural Pattern to Service Oriented ...

Chapter 4. Service Oriented Architecture 93mean of communication. Pattern application eliminates bridging servicesin the system what improves performance and maintainability. In order toincrease benefits associated with the pattern, architects should consider usageof widely supported and vendor independent communication protocolslike SOAP.Rationale:Enforcing usage of one specific protocol by every single servicein an inventory has a large impact on communication within the system.3. Canonical Schema –Many services perform operation on the same data thatare modeled differently by different vendors or teams. Those differencesincrease development efforts and make design more complex. Additionally,the transformation between different models introduces performance drop.The pattern standardizes data model for information within the inventory.The motivation behind the pattern is to avoid translation between differentdefinitions of the same data and eliminate data definition redundancy acrossthe system.Rationale:Forces services to use predefined schemas. Service cannot defineown ’implementation’. The pattern influences every service in the system.4. Utility Abstraction –Services, even those that do not provide redundantfunctionality may perform some common operation. Those operations areredundant. The redundancy requires additional effort for testing and maintenance.Utility Abstraction defines one layer containing common utilityservices. The layer contains mainly services without business concern, thereforein opposite to business-based services, utility services are developedmainly by architects and developers what raises problems related to contentof such service. Teams need good communication in order to avoidredundant services.Rationale:Enriches structure of Service Layers, what also changes flow ofmessages in the system.5. Entity Abstraction –Many business processes uses the same business entities.It is very likely that the functionality is implemented several times indifferent services. This raises problems with maintenance and testability.Entity Abstraction introduces another layer into layered structure. Thelayer contains services performing operation on business entities.Rationale: See Utility Abstraction rationale.6. Process Abstraction –Grouping of business process services together withnon-business process services makes harder maintenance of both types ofthe services. It is harder to change processes and maintain functionality