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

Chapter 4. Service Oriented Architecture 78(b) Logic Centric Services– correspond to algorithms and business ruleslibraries in monolithic systems.The definitions clearly show that there are two types of basic services butin practice, it is very hard to create pure Data Centric Service or pure LogicCentric Service.3. Intermediary Service [46] [31] – are stateless mediators that serve as bridgesbetween services. They may be categorized into Gatways, Adapters, Facadesand functionality adding services. Because they connect very specificservices, reusability of Intermediary services is much lower than reusabilityof Basic Services.4. Public Enterprise Service [46] – Enterprise level public services are veryrare entities. They make available their functionality outside a company inopposite to other types of services. They have to be loosely coupled andwell described on business level. Those issues raise security problems, whichmay occur and generate more problems than services within a company.5. Process Centric Service [31] – encapsulates and executes a part of processlogicof a company. This type of service is the most complex. ProcessCentric Service is less reusable and does not contribute too much to functionalinfrastructure of SOA due to its complexity and narrowed usage [46].Nevertheless, its process control is essential for the organization [34]. Inspite of its complex structure and lowered reusability, Process Centric Servicebring some benefits, which are especially important in applications thathave to guarantee simultaneous access for many users. Those benefits are:(a) Process encapsulation [46] [31][59] [13]– Process Centric Service hidesand encapsulates hermetically structure of the process. This supportsdesigning of architecture may be expressed as a set of Process CentricServices implementing processes. Encapsulation improves testabilityof the system and allows different teams to work on different parts ofthe system simultaneously.(b) Load balancing simplification [46]– clear separation of processes supportsparallel executing what is very important for applications thatare characterised by short response time.(c) Support for multi-channel application [46] –multi-channel applicationsare [86] applications enabling users to access them by using a variety ofdevices like personal computer, mobile phones or any other device thatcan connect to the web. Each of these devices is called ’a channel’.In fact, multi-channel application is a set of interfaces for the same