Migration of a Chosen Architectural Pattern to Service Oriented ...
Migration of a Chosen Architectural Pattern to Service Oriented ...
Migration of a Chosen Architectural Pattern to Service Oriented ...
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Chapter 4. <strong>Service</strong> <strong>Oriented</strong> Architecture 80Figure 4.1: Relationship between SOA elements4.3 SOA – business point <strong>of</strong> viewOne <strong>of</strong> the goals <strong>of</strong> SOA is <strong>to</strong> align the business. It is very important <strong>to</strong>establish business context and define boundaries <strong>of</strong> the system by a managementteam[6].There is no SOA without proper analysis. The need <strong>of</strong> properbusiness analysis in order <strong>to</strong> separate services and their relationships was notifiedand resulted in organized methodologies like <strong>Service</strong> <strong>Oriented</strong> ModelingAnalysis (SOMA) [6],[11] and supporting <strong>Service</strong> <strong>Oriented</strong> Modeling Framework(SOMF) [11]. There are also other approaches like presented by T.Erl [19] or N.Bieberstein[13]. This section presents SOA from business perspective.1. Properties <strong>of</strong> <strong>Service</strong>s – presents basic properties <strong>of</strong> services.2. Activities – describes activities executed during designing SOA.4.3.1 Properties <strong>of</strong> <strong>Service</strong>sCompanies that decided <strong>to</strong> introduce <strong>Service</strong> <strong>Oriented</strong> Architecture <strong>to</strong> their systemschoose also specific approach for analysis and design. Analysis selects themost suitable candidates for services. Each candidate is characterized by followingproperties [13]:reuse, encapsulation, coupling, cohesion and granularity.Reuse – services should be designed keeping high reuse in mind. The importance<strong>of</strong> service reuse is explained in details in benefits section (4.7), which fullymotivate high reuse <strong>of</strong> a service.Encapsulation [13] – hides implementation information from cus<strong>to</strong>mers <strong>of</strong> aservice by making services accessible only via their interfaces. There are consumerswho consume the service. The consumption shall not depend on underling