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The service reusability principle is a design principle that is applied within the service-orientation design paradigm, in order to create services〔(Services )〕 that have the potential to be reused across the enterprise.〔Thomas Erl, Herbjörn Wilhelmsen (SOA Pattern of the Week (#4): Service Normalization )(). Date accessed: 14 April 2010.〕 These reusable services are designed in a manner so that their solution logic is independent of any particular business process or technology. ==Purpose== Service reusability is usually measured in terms of how much extra functionality does a service contain which could be reused in future and how much of the service’s functionality goes beyond the current requirements. This encourages services that contain extra capabilities which are built around possible future service usage scenarios. However, little is done in designing the service logic in a manner that it could be reused to automate multiple business processes. So, there is more focus on equipping services with extra functionality than actually concentrating on making the core service logic reusable. This leads to gold-plated services whose development require increased time and efforts. This additional functionality may not even fall within the original functional context〔The type of the functionality that a service encloses e.g. an Invoice service will have a functional context that deals with invoice related processing but will not deal with processing Purchase Orders〕 of the service and might not even be used at all, as it was built without establishing its needs. Most important of all, the resulting SOA would not be able to provide true service reusability as promised. Another misconception about service reuse is that the reuse relates to the frequency of its usage. Contrary to this, the actual reuse relates to when the service is used to automate multiple business processes. This is the true service reuse as such a service eliminates the need for creating altogether a new service and becomes a part of multiple business processes without being part of any particular business process. The service reusability principle addresses these misconceptions by providing a set of guidelines that help to design services containing logic which is not linked to any particular business process and hence could be reused across the enterprise for automating multiple business processes. This further helps in achieving increased ROI.〔Hariharan.(Common mistake while adopting SOA )(). Date accessed: 14 April 2010.〕 The compound application of service reusability, service abstraction and service loose coupling principles help developing composable services.〔Kjell-Sverre Jerijærvi.(SOA Contract Maturity Model )(). Date accessed: 14 April 2010.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Service reusability principle」の詳細全文を読む スポンサード リンク
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