The Specifications of a Generic QoS Metamodel for Designing and Developing Good Quality Web Services

DOI: 10.5176/978-981-08-6308-1_D-017

Authors: Wan Nurhayati Wan ab. Rahman, Farid Meziane

Abstract:

Quality of Service (QoS) is crucial in the design of web services as it allows the development of good, efficient and usable web services. Unfortunately, current research on the QoS for web services is concentrated on service users and implementation. Consequently, web services still suffer from a lack of quality. Our research highlights the importance of incorporating QoS early in the design and development of web services. More precisely, we advocate the introduction of QoS as early as the specification phase and to be performed at the same time as the specification of functional requirements. A web service is based on serviceoriented architecture (SOA) and the basic technologies for web services standards include Simple Object Access Protocol (SOAP), Web Service Description Language (WSDL) and Universal Description, Discovery and Integration (UDDI). However, WSDL only describes the functional elements of a web service and yet QoS is significant for the web service description. Therefore, this paper proposes a lightweight extension to the WSDL through our generic QoS metamodel to incorporate QoS specifications. The main purpose of the QoS metamodel is to guide service providers to identify functionalities that could be extended and to determine suitable QoS specifications that could be applied together with their QoS dimensions. This paper begins with defining the required QoS specifications for the development of good quality web services and then explores the potential to use the Unified Modeling Language (UML) as a technique and notation to specify QoS. To properly integrate QoS in the design, we propose extensions to the existing UML QoS profile. The paper concludes with the evaluation of our proposed framework and summarises its merits.