Correct-by-Construction Web Service Architecture

Abstract—Service-Oriented Computing aims to facilitate devel-opment of large-scale applications out of loosely coupled services. The service architecture sets the framework for achieving cohe-rence and interoperability despite service autonomy and the hete-rogeneity in data representation and protocols. Service-Oriented Architectures are based on standardized service contracts, in order to infuse characteristic properties (stateless interactions, atomicity etc). However, contracts cannot ensure correctness of services if essential operational details are overlooked, as is usually the case. We introduce a modeling framework for the specification of Web Service architectures, in terms of formal operational semantics. Our approach aims to enable rigorous design of Web Services, based on the Behaviour Interaction Priorities (BIP) component framework and the principles of correctness-by-construction. We provide executable BIP models for SOAP-based and RESTful Web Services and for a service ar-chitecture with session replication. The architectures are treated as reusable design artifacts that may be composed, such that their characteristic properties are preserved

Exploiting the architectural characteristics of software components to improve software reuse

PhD ThesisSoftware development is a costly process for all but the most trivial systems. One of the commonly known ways of minimizing development costs is to re-use previously built software components. However, a significant problem that source-code re-users encounter is the difficulty of finding components that not only provide the functionality they need but also conform to the architecture of the system they are building. To facilitate finding reusable components there is a need to establish an appropriate mechanism for matching the key architectural characteristics of the available source-code components against the characteristics of the system being built. This research develops a precise characterization of the architectural characteristics of source-code components, and investigates a new way to describe how appropriate components for re-use can be identified and categorized.Umm Al- Qura University

Design time detection of architectural mismatches in service oriented architectures

Service Oriented Architecture (SOA) is a software component paradigm that has the potential to allow for exible systems that are loosely coupled to each other. They are discoverable entities that may be bound to at run time by a client who is able to use the service correctly by referring to the service's description documents. Assumptions often have to be made in any design process if the problem domain is not fully speci ed. If those decisions are about the software architecture of that component and it is inserted into a system with di ering and incompatible assumptions then we say that an architectural mismatch exists. Architectural styles are a form of software reuse. They can simply be used by referring to a name such as \client-server" or \pipe and lter", where these names may conjure up topologies and expected properties in the architects mind. They can also however be more rigorously de ned given the right software environment. This can lead to a vocabulary of elements in the system, de ned properties of those elements along with rules and analysis to either show correctness of an implementation or reveal some emergent property of the whole. SOA includes a requirement that the service components make available descriptions of themselves, indicating how they are to be used. With this in mind and assuming we have a suitable description of the client application it should be the case that we can detect architectural mismatches when designing a new system. Here designing can range from organising a set of existing components into a novel con guration through to devising an entirely new set of components for an SOA. This work investigates the above statement using Web Services as the SOA implementation and found that, to a degree, the above statement is true. The only element of description required for a web service is the Web Service Description Language (WSDL) document and this does indeed allow the detection of a small number of mismatches when represented using our minimal web service architectural style. However from the literature we nd that the above mismatches are only a subset of those that we argue should be detectable. In response to this we produce an enhanced web service architectural style containing properties and analysis supporting the detection of this more complete set of mismatches and demonstrate its e ectiveness against a number of case studies.EThOS - Electronic Theses Online ServiceGBUnited Kingdo