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

Chapter 3. Architectural Patterns 64exist neither in MVC nor in PAC. The connectors specify more precisely way ofcommunication between elements. Summarizing, MVC pattern is the most generalpattern within the category and becomes representative of User InteractionView.Representative: Model–View–ControllerComponent Interaction ViewCandidates: Explicit Invocation, Implicit Invocation, Client–Server, Peer–to –Peer,Half–Sync / Half–AsyncSelection: Pattern descriptions presented in section 3.2.1 underlines similaritiesbetween Explicit invocation, Implicit Invocation and Client–Server. Client–Serverdefines division of a system into two parts. Explicit and Implicit Invocations alsomake this division but they also introduce new elements determining communicationdetails between Client–Server parts. They are just variants of Client–Serverpattern, therefore Client-Server is more general in terms of previously stated criteria.Peer–to–Peer pattern describes interaction between elements that are clientsand servers in the same time. In fact, this pattern crates a network of modifiedClient-Server entities. The problem appears when a comparison between Client-Server and Half–sync/half–async has to be made. The problem is that those twopatterns describe different model of connection between components. Responsibilitiesof elements those two patterns are incomparable. Parts of Half–Sync/ Half–async pattern in opposite to Client–Server take care about two differentaspects of communication, therefore those two patterns cannot compared to eachother. The Component Interaction view has two representatives.Representative: Half–Sync / Half–Async, Client–ServerDistribution ViewCandidates: Broker,Remote Procedure Call, Message QueueingSelection: Distribution View contains three architectural patterns. The firstin row is Broker. The description of Broker pattern underlines similarities betweenthis pattern and previous category. The structure and functionality of thispattern matches description of Client –Server pattern. In fact, Broker is just amore complex version of Client–Server; therefore, this pattern will not be comparedwith patterns from Distribution View and shall be moved to ComponentInteraction View. Since this pattern is a more complex version of Client–Server,Broker is not a representative of Component Interaction View. Remote ProcedureCall does not have fixed structure. It is rather an idea how to keep connectionsbetween different parts of distributed systems masked. The patterns are incomparable;consequently, this view has also two representatives–both are differentin terms of their structure and functionality.Representative: Remote Procedure Call, Message Queueing