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 Basci & 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.

Lightweight Semantic based Approach to Assess Readability of Web Service Interfaces

A Web Service has an interface described in a machine-processable format (specifically WSDL). Service providers expose their services by publishing their WSDL documents. Service consumers can learn about service capabilities and how to interact with services.Service descriptions (WSDL documents) should be ideally understood easily by service stakeholders so that the process of consuming services is simplified. In this work we present a practical metric to quantify readability in WSDL documents. We adapted and extended an existing ontology-based semantic readability metric to focus on WSDL documents by using WordNet as a lightweight concept hierarchy. We have validated our approach by performing both qualitative and quantitative experiments. The first one consists of a controlled survey with a group of service consumers. The results showed that consumers (software engineers) required less time and effort to analyze WSDL documents with higher readability values. The second experiment compares our approach with two ontology-based approaches. The third experiment compares the readability values of a dataset of real-life service descriptions before and after rewriting them. The resultsshowed the effectiveness of our approach to assess readability of Web Services interfaces.

A Stitch in Time Saves Nine: Early Improving Code-First Web Services Discoverability

Web Services represent a number of standard technologies and methodologies that allow developers to build applications under the Service-Oriented Computing paradigm. Within these, the WSDL language is used for representing Web Service interfaces, while code-first remains the de facto standard for building such interfaces. Previous studies with contract-first Web Services have shown that avoiding a specific catalog of bad WSDL specification practices, or anti-patterns, can reward Web Service publishers as service understandability and discoverability are considerably improved. In this paper, we study a number of simple and well-known code service refactorings that early reduce anti-pattern occurrences in WSDL documents. This relationship relies upon a statistical correlation between common OO metrics taken on a service's code and the anti-pattern occurrences in the generated WSDL document. We quantify the effects of the refactorings — which directly modify OO metric values and indirectly alter anti-pattern occurrences — on service discovery. All in all, we show that by applying the studied refactorings, anti-patterns are reduced and Web Service discovery is significantly improved. For the experiments, a dataset of real-world Web Services and an academic service registry have been employed.

Estimating Web Service interface quality through conventional object-oriented metrics

Historically, software engineers have conceived metric suites as valuable tools to estimate the quality of their software artifacts. Recently, a fresh computing paradigm called Service-Oriented Computing (SOC) has emerged at the crossing of massively distributed and heterogeneous software.This paper presents a statistical correlation analysis showing that classic software engineering metrics can be used to predict the most relevant quality attributes of WSDL documents, the essential software artifact when materializing this novel computing paradigm withWeb-based technologies. For the experiments, two recent WSDL-level metrics catalogs and 154 real world WSDL documents have been employed.