Service Identification Methods: A Systematic Literature Review <s> W2 (Business Functions) <s> A successful implementation of a service oriented architecture demands for a systematic identification of the information system functions to be implemented as services. In contrast to other approaches attempting to transfer each existing function in a company into a service, the method presented in this paper proposes a selective identification of services from a business point of view, based on process models. Functions are rated due to their outsourcing and visibility potential for stakeholders. Functions are only implemented and provided as a service, if both business potential and technical feasibility have been verified. Having been evaluated in a medium-sized manufacturing company, the approach and the results of the evaluation can also facilitate a sound service identification in other companies. <s> BIB001 </s> Service Identification Methods: A Systematic Literature Review <s> W2 (Business Functions) <s> User interface (UI) design is an integral part of the software design process. The UI design not only outlines the look and feel of the system, but also helps in flushing out the requirements - by identifying what data is visible to and processed by different users. However, in any SOA methodology, UI design is typically considered out of scope. In this paper, we highlight the importance of UI design specification in the SOA landscape, from a service- identification perspective. Service identification, which is a key activity in any SOA-based development, involves specification of business requirements as a set of granular service definitions. We propose an approach for harvesting the UI design specification to define service requirements for the intended system; more specifically in terms of information and business service requirements. Our approach consists of the following steps: (1) capture user interface design in a format amenable to automated analysis, with appropriate references to data and process models, (2) identify requirements for information services from data that is displayed in the user interface, and (3) identify business service requirements from the UI navigation flow and the links between the UI and the business process model. To illustrate our approach, we present a case study using the Amazon associate Web services. The study demonstrates how the use of UI designs can lead to better service identification. The proposed approach can complement any existing SOA methodology that follows a top-down approach to identify services. <s> BIB002
Decompose business function models that depict what an organization does S1,S2,S8,S9,S11,S18, S19,S22,S28 Four strategies (W6, 8, 9, 10) are discussed in  but have not been used by any of the SIMs that we studied. As explained in  , W6 has practical difficulties due to the different nature of component and services; W8 might be risky if existing application design is of low quality; and W9 results in services heavily coupled with infrastructure. Due to these issues, it is understandable that the SIMs avoid using these strategies. W10 points out the importance of nonfunctional requirements (NFRs) in SI as conflicting NRFs might cause redesign. As no SIM relies on W10, further research is required in supporting NFRs. Interestingly, we also identified a new strategy, W11 user interface (not discussed in  ). User interface (UI) design, an integral part of the software design process, is often considered out of scope of SOA design BIB002 . However, a UI design helps one to distinguish the purely presentation aspects from data and process aspects and hence aids the identification of services. The use of UI design in SI is regarded as an innovative approach. Some SIMs use only one strategy (W1, 2, 3 or 7) and we call these strategies primary strategies; while the others are always used in combination with the primary strategies and we call them complementary strategies. The most popular primary strategies are W1, 2 and 7, used by 13, 9 and 7 SIMs respectively. The first two are top-down approaches by examining the business requirements while the last one represents a bottom-up approach by extracting valuable and/or reusable functions from existing applications. In most of the cases, the strategies used by a SIM are directly related to its input. E.g., all the SIMs that use business process as their input use W1 (decompose business process) as its strategy, only S15 exceptionally uses a combination of W4 and W11. The complementary strategies are W4, 5 and W11 which are specifically aided by the information about goals, stakeholders and user interfaces. However, this information alone is often not sufficient for identifying services. For instance, in S15 user interfaces are first designed based on business process decomposition and then services are identified by extracting abstract WSDL specifications from user interface specifications. Obviously using W11 (user interface) only is not sufficient in this example. The use of these complementary strategies often results in services more business-driven as explained in e.g. BIB001 . Techniques. After studying the data about the techniques used in the SIMs, we have identified six different types of techniques, summarized in Table 5 .