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

Chapter 4. Service Oriented Architecture 90pattern), design of a single component (typical design pattern) or maybe designof a process (process pattern)(see section 3.1.1). The distinction grows in importancewhen architectural knowledge is taken into consideration. ArchitecturalKnowledge is meant to describe an architecture and rationale behind decisionmade during architecture designing [9]. The decisions do not refer only to rationaleof fine-grained components but also to a “big picture” – system architecture.Architecture requires more detailed studies, due to a large-scale impact on system.This subsection describes SOA architectural patterns in following manner..1. SOA patterns– presents a problem with SOA architectural patterns andpresents results of pattern investigation.2. The target architecture – presents the target architecture that is a result ofcombination of patterns found in section 4.6.14.6.1 SOA patternsThe book “SOA –Design Patterns” [32] is the largest and the most completesource of pattern in SOA domain[54]. Patterns presented in the book belong todesign patterns, but their descriptions question this adherence. The problem risesfrom definition of pattern and design pattern used by T.Erl in this book.According to T.Erl pattern [32]“provides a proven solution to a common problemindividually documented in a consistent format and usually as part of a largercollection” what corresponds to the definition of pattern presented in section 3.1.1.Design pattern is defined as follows [32]: “Patterns in the IT world that revolvearound the design of automated systems are referred to as design patterns.”.Thisdefinition can be also applied to other types of patterns. All the pattern describedin section 3.1.1 “revolve” around design of automated system, not only designpatterns.SOA patterns are described also in“Patterns: Service–Oriented Architectureand Web Services”[30] but they refer to Enterprise Application Integration. Integrationis out scope of this thesis.Selection of architectural patternsThe target architecture will be build on architectural patterns. Usage of the book“SOA –Design Patterns” [32] as a source of architectural patterns requires furtherstudies.Analysis of patterns presented by T. Erl (see [32]) results in division of presentedpattern into four categories. The categories are following