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

Chapter 5. Guidelines 115ViewSchemaViewController+ Canonical Schema =ControllerModelModelFigure 5.3: Migration step 3How to: Services may implement policies. The policies can be commonfor a group of services. The common parts should be shared (see figure5.4). Policies and security in SOA is a very wide and complex domain, thatincludes different messaging types, security description files (WSPolicy), encodingand many others. This guideline identifies moment during migrationwhen this aspect should be considered. Information about security relatedissues should be investigated in existing documentation. Implementation isa project specific task.SchemaViewSchemaViewPolicyController+ Policy Centralisation =ControllerModelModelFigure 5.4: Migration step 45. Identify and wrap into services all coarse grained utilitiesApplied SOA pattern: Utility AbstractionHow to: Unlike Core Business logic services, utility services usually are notdesigned by people responsible for business process planning . Utility Servicesare basic services and they contain general purpose functionalities likefor instance event logging facilities. They are created mainly by architectsand developers [32]in order to simplify and support current architecture.Separation of utility functionality is difficult. The difficulties derive fromrole of utilities. They can be used anywhere. Starting from GraphicalUser Interface (for instance Java SWING has a lot of utility functionalities)through advanced text parsers supporting Core Business logic to Loggingcomponents that may log events from all elements of the system. The next