Verification of Web Services Modeled as Finite State Machines

Abstract

Currently, model based development of web services is being actively researched for its usefulness in developing a system. Various techniques like EPC, petrinet, process algebra, CPN and UML have been proposed for web service modeling. FSM is found appropriate to model Business requirements because a business process on execution moves forward from one state to other. We have shown uses of FSM (Finite State Machine) based models in development of web services [1]; also have developed a tool HUMSAT to model service specification in FSM and to generate executable codes in BPEL and WSDL. However, automated code generation depends on correct specification of models as an improperly specified model leads to errors and bugs in resultant code. Hence model checking plays an important role in eliminating the flaws at design phase itself. In this paper, we propose a technique for model verification that identifies structural flaws e.g. unreachability, deadlock and temporal inconsistencies. Further, HUMSAT is augmented with the model verification features.

Context based behavioural verification of composed web services modeled in finite state machines

“…In our earlier work [8] service. AFSM is defined with constructs choice, flow and synchronization for modelling webservices.…”

“…However improper use of modelling constructs results in both structural as well as behavioural errors. In [8] we have identified and proposed a method to avoid the structural errors as these are the main causes for behavioural errors. The identified structural flaws include unreachable activities in a service, deadlock issues due to incorrect usage of synchronization, improper temporal constraints and missing choice paths.…”

“…Here in this paper we model a service with AFSM and the service verification is performed at two levels one is structural and the other behavioural. The former one verifies the structural errors in modeled service and this work is reported in [8]. Tthe later one checks the compliance of service run time behaviour (during execution) with that of modelled service.…”

“…Here we give an overview of the existing service specification proposed in [8]. AFSM was proposed to describe business process, where larger complex process is modelled as set of smaller steps, i.e states of FSM.…”

Formal Modeling and Verification for Web Service Composition

“…The process of web service composition is usually an error-prone pratice.If the process definition without being verified becomes operational,it often results in runtime errors, which causes software maintenance costly.To solve this problem,many researchers propose a lot of solutions.For example,using SPIN modeling tools verify web service composition whose language is WSFL.Using PAC and CWB-IN tools model and verify web service composition whose language is BPEL4WS based on BPE calculus. However these solutions are usually dependent on the concrete flow description language [5] [15].…”