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

Chapter 5. Guidelines 106Context An application is composed of many services that are developedby different teams.Forces(a) Many services provide similar functionality.(b) Functionality of each service is different.(c) High cohesion of services has to be kept.Solution The pattern divides service inventory into logical layers containingservices with similar functionality. Each layer contains one specificand abstract concern. The pattern enforces usage of at least two layers-onecontains basic service, the other contains composed services.Result Context The application is divided into several (at least two)service layers that support maintainability and further development of thisapplication.2. Name Canonical ProtocolProblem Service can be provided by different vendors. The vendors canuse different languages and communication protocols. However the differencein language is not so important, the differences in communicationprotocols are. Different communication protocols limit number of potentialconsumers and introduce the need of protocol bridging.Context An application is composed of services that are delivered bydifferent vendors.Forces(a) Services need to communicate with each other(b) A main way of communication needs to be established(c) A way of communication cannot limit functionality of servicesSolution Application of the pattern enforces usage of one communicationprotocol as a main mean of communication. Pattern application eliminatesbridging services in the system what improves performance and maintainability.In order to increase benefits associated with the pattern, architectsshould consider usage of widely supported and vendor independent communicationprotocols like SOAP