Design for adaptation of service-based applications: main issues and requirements

Service-based applications are considered a promising technology since they are able to offer complex and flexible functionalities in widely distributed environments by composing different types of services. These applications have to be adaptable to unforeseen changes in the functionality offered by component services and to their unavailability or decreasing performances. Furthermore, when applications are made available to a high number of potential users, they should also be able to dynamically adapt to the current context of use as well as to specific requirements and needs of the specific users. In order to address these issues, mechanisms that enable adaptation should be introduced in the life-cycle of applications, both in the design and in the runtime phases. In this paper we propose an extension of a basic iterative service-based applications lifecycle with elements able to deal with the adaptation-specific needs. We focus, in particular, on the design phase and suggest a number of design principles and guidelines that are suitable to enable adaptation. We discuss about the effectiveness of the proposed methodology by means of real-world scenarios over various types of service-based applications.