Synthesizing adapters for conversational web-services from their WSDL interface

Abstract

Service-oriented applications are typically built out of existing web-services (WSs) possibly made available by third party vendors. This requires that the application has to be able to evolve when the composing WSs are not anymore available or when new, more useful ones, are published. In this setting, an important problem is to understand how to use WSs showing an interface that differs from the one the application has been built to. The problem becomes even more complex when we consider conversational WSs, i.e., WSs that expose operations that have Input/Output (I/O) data dependencies among them. This paper presents a complete development methodology to the automatic synthesis of adapters for conversational WSs starting from their WSDL interface. The result is a tool-supported methodology that takes as input the WSDL of a pair of services and automatically builds a script that maps a sequence of operation invocations on a "WS to be replaced" into an equivalent sequence of operation invocations on the "replacing WS". The overall approach is presented by applying it to two existing WSs that realize two distinct, but equivalent, search engines for lyric music.

A formal approach to adaptive software: continuous assurance of non-functional requirements

“…This is an area in which research is quite active internationally, and several approaches are currently investigated (see [18,46]) to devise strategies for implementing changes in the model and in the implementation as the need for self-adaptation is recognized. Most proposals, including some work developed in our group ( [17,28]), are still quite preliminary and hard to assess and compare. No approach seems to be sufficiently general and scalability is often an issue.…”

When the requirements for adaptation and high integrity meet

“…Model-driven development @ runtime techniques were recently proposed [3,9,20] for the on-line synthesis of interfaces (or connectors) between the dynamically selected components of self-adaptive software systems. The approach is currently applicable to service-oriented software architectures, whose web service components expose standardsbased WSDL "models" [3,9].…”

“…The approach is currently applicable to service-oriented software architectures, whose web service components expose standardsbased WSDL "models" [3,9]. These models are used to synthesise the connectors required to integrate new components into an existing software architecture as part of the adaptation process, while the framework proposed in [20] enables the formal characterisation and verification of these connectors.…”

“…[3,9,20] software lifecycle. Accordingly, they operate with models, properties, assumptions and conjectures that in the case of self-adaptive software are unknown until the application is deployed and running-and which change over time.…”

Evaluating the compatibility of conversational service interactions

“…Conversational services impose a specific interaction protocol, as well as specific data types, and some sort of adapter may be required [9]. In this paper we present an approach that tells the designer how and where to adapt the system to support the substitute service.…”