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

Chapter 5. Guidelines 116problem is granularity of utility functionalities. While Logging is coarsegrained, SWING utilities support fine grained issues like “boolean isRectangleContainingRectangle(Rectanglea, Rectangle b)” method. Such fineutilities should not be taken into consideration during Utility Abstractiondesigning. Garrulity itself is rather hard to define, thus an architect or adeveloper shall decide whether granularity shall be defined based on size ofcode of the utility or other criterion is needed. Model of MVC is the placewhere utility code should be found (see 5.5).ViewSchemaViewPolicySchemaControllerPolicyController+ Utility Abstraction =Basic ServicesModelUtilityFigure 5.5: Migration step 56. Identify and encapsulate access to any external resourceApplied SOA pattern: Canonical ResourcesHow to: Canonical Resource wraps an access to any external resource usedby application. Term “external resource” refers to databases, state deferralmechanisms (mechanisms that allow to store temporary state of a service),activity management extensions (like context and transaction managementframeworks)[32]etc. It does not include resources like CPU or memoryif they belong to the host machine. Model should be checked in termsof having any connection to databases, outside company services or othercomponents storing and maintaining data like for instance service grids.Depending on resource granularity (for instance database size) and complexityof operations executed on the resource, a new service may providean access to the resource or to operations on resource related to particularentities (see 5.6).7. Identify and wrap into services all entity related codeApplied SOA pattern: Entity AbstractionHow to: Entity–related Core logic of migrated system should be investigatedin components elements that manipulate entities. The manipulationincludes mainly computations and entity-related tasks. Entity related servicescan be understood as services providing utilities for entities and shouldbe found in Model (see 5.7).