Managing Web Service Interface Complexity via an OO Metric-based Early Approach

Web Services have been steadily gaining maturity as their adoption in the software industry grew. Accordingly, metric suites for assessing different quality attributes of Web Service artifacts have been proposed recently – e.g., for services interfaces in WSDL (Web Service Description Language). Like any other software artifact, WSDL documents have several inherent attributes (e.g., size or complexity) that can be measured. We present an approach to prevent a high complexity on services interfaces (WSDLs), to ease consumers to reason about services’ offered functionality. Mostly, WSDLs are automatically derived from object-oriented (OO) source code, with a likely impact on complexity. Thereby, we study the statistical relationships between a recent metric suite of service interface complexity (proposed by Baski & Misra) and the well-known Chidamber & Kemerer’s OO metric suite (applied to service implementations), on a data-set of 154 real-world services. First, a theoretical validation of Baski & Misra’s suite (using Weyuker’s properties) is presented, to prove the ability to measure complexity in WSDL documents. Then, after finding high correlation between both metric suites, we have conducted a series of experiments to analyze how certain refactorings on services’ source codes prior to derive WSDLs might reduce complexity. In this way, our approach exploits OO metrics as development-time indicators, to guide software developers towards obtaining less complex service interfaces.