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

Chapter 5. Guidelines 113System’s services are created based on an available code. The documentation isused to consult if a question arises. The description below presents guidelines witha “How to” section. Additionally a figure presenting current step of migrationis provided. Each figure contains green elements. The element between + and= represents introduced SOA architectural pattern. The second green elementpresents change to architecture.5.2.1 Description of Guidelines1. Convert MVC into layersApplied SOA pattern: Service LayersHow to: Service layering simplifies service maintenance. The main ideabehind the pattern is to divide services having similar characteristic intoseparate layers (see figure 5.1). The characteristic of services is describedby its functionality, technical aspects, complexity or other properties thatallow grouping services. Structure of considered pattern has to be analyzedin terms of its components and connections between them. Elements ofthe architectural pattern are converted into layers. Original dependenciesbetween elements of MVC should be removed. Layers allow dependenciesonly in one direction (top–down). Introduction of this pattern simplifiesfurther migration because the pattern frames architecture.ViewViewController+ Service layers =ControllerModelModelFigure 5.1: Migration step 12. Choose main communication protocolApplied SOA pattern: Canonical ProtocolHow to: Canonical Protocol recommends usage of one major communicationProtocol (see figure 5.2).. In fact the choice is not limited to onlyone protocol, because communication is transport plus message description