Interface adaptation for conversational services

Wang, Kenneth W.S. (2008) Interface adaptation for conversational services. PhD thesis, Queensland University of Technology.


The proliferation of services on the web is leading to the formation of service ecosystems wherein services interact with one another in ways not foreseen during their development or deployment. This means that over its lifetime, a service is likely to be reused across multiple interactions, such that in each of them a different interface is required from it. Implementing, testing, deploying, and maintaining adapters to deal with this multiplicity of required interfaces can be costly and error-prone. The problem is compounded in the case of services that do not follow simple request-response interactions, but instead engage in conversations comprising arbitrary patterns of message exchanges. A key challenge in this setting is service mediation: the act of retrofitting existing services by intercepting, storing, transforming, and (re-)routing messages going into and out of these services so they can interact in ways not originally foreseen. This thesis addresses one aspect of service mediation, namely service interface adaptation. This problem arises when the interface that a service provides does not match the interface that it is expected to provide in a given interaction. Specifically, the thesis focuses on the reconciliation of mismatches between behavioural interfaces, that is, interfaces that capture ordering constraints between message exchanges. We develop three complementary proposals. Firstly, we propose a visual language for specifying adapters for conversational services. The language is based on a an algebra of operators that are composed to define links between provided-required interfaces. These expressions are fed into an execution engine that intercepts, buffers, transforms and forwards messages to enact the adapter specification. Secondly, we endow such adapter specifications with a formal semantics defined in terms of Petri nets. The formal semantics is used to statically check the correctness of adapter specifications. Finally, we propose an alternative approach to service interface adaptation that does not require hard-wired links between provided and required interfaces. This alternative approach is based on the definition of mapping rules between message types, and is embodied in an adaptation machine. The adaptation machine sits between pairs of services and manipulates the exchanged messages according to a repository of mapping rules. The adaptation machine is also able to detect deadlocks and information loss at runtime.

Impact and interest:

Search Google Scholar™

Citation counts are sourced monthly from Scopus and Web of Science® citation databases.

These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.

Citations counts from the Google Scholar™ indexing service can be viewed at the linked Google Scholar™ search.

Full-text downloads:

360 since deposited on 04 Mar 2009
6 in the past twelve months

Full-text downloads displays the total number of times this work’s files (e.g., a PDF) have been downloaded from QUT ePrints as well as the number of downloads in the previous 365 days. The count includes downloads for all files if a work has more than one.

ID Code: 18465
Item Type: QUT Thesis (PhD)
Supervisor: Ouyang, Chun
Keywords: service-oriented architecture, web services, conversational services, service mediation, service adaptation, behavioural/protocol adaptation, adapter formalisation, operational semantics
Divisions: Past > QUT Faculties & Divisions > Faculty of Science and Technology
Institution: Queensland University of Technology
Deposited On: 04 Mar 2009 01:32
Last Modified: 09 Feb 2011 13:53

Export: EndNote | Dublin Core | BibTeX

Repository Staff Only: item control page