Valérie Monfort

A concrete solution for web services adaptability using policies and aspects

Traditional middleware is usually developed on monolithic and non-evolving entities, resulting in a lack of flexibility and interoperability. Among current architectures, Service Oriented Architectures aim to easily develop more adaptable Information Systems. Most often, Web Service is the fitted technical solution which provides the required loose coupling to achieve such architectures. However there is still much to be done in order to obtain a genuinely flawless Web Service, and current market implementations still do not provide adaptable Web Service behavior depending on the service contract. Therefore, our approach considers Aspect Oriented Programming (AOP) as a new design solution for Web Services. Based on both WSDL and Policies contracts, this solution aims to allow better flexibility on both the client and server side. In this paper we expose our technical and concrete solution using Axis as the SOAP Engine, WSS4J as the WS-Security handler, and Javassist to weave some non-functional security aspects depending on the policies requirements.

Applying AOP concepts to increase Web services flexibility

Web service is the fitted technical solution which provides the required loose coupling to achieve service oriented architecture (SOA). In previous works, we propose an approach, using the aspect oriented programming (AOP) paradigm, to increase the adaptability of Web services. This approach suffers from some deficiencies as dependency for both the programming language (Java) and the SOAP engine (AXIS). In this paper, we propose to increase the adaptability of Web services by using the main AOP agreed semantics - advices, pointcuts and joinpoint - to change original Web service behavior. In the new approach we consider that advices are themselves a Web service. Moreover, we propose to use an XML language for describe pointcuts, joinpoint and to referencing advices. The invocation of advices (Web services) is accomplished by an XQuery engine to assure SOAP engine independency and advices are implemented as Web services to promote programming language independency.

CONCRETE SOLUTIONS FOR WEB SERVICES ADAPTABILITY USING POLICIES AND ASPECTS

Traditional middleware is usually developed on monolithic and non-evolving entities, resulting in a lack of flexibility and interoperability. Among current architectures, Service Oriented Architectures aim to easily develop more adaptable Information Systems. Most often, Web Service is the fitted technical solution which provides the required loose coupling to achieve such architectures. However, there is still much to be done in order to obtain a genuinely flawless Web Service, and current market implementations still do not provide adaptable Web Service behavior depending on the service contract. In this paper, we present our two last years of work toward a more adaptable SOA. We proposed two approaches that consider Aspect Oriented Programming (AOP) as a new design solution for Web Services. The two approaches enable us to glue new non-functional behaviors to a Web Service without going back to modify, recompile, retest and finally redeploy it.

Towards Adaptable SOA: Model Driven Development, Context and Aspect

Service-Oriented Architectures (SOA) are broadly used by companies to gain in flexibility. Web service is the fitted technical solution used to support SOA by providing interoperability and loose coupling. However, there is still much to be done in order to obtain a genuine flawless Web service, and current market implementations still do not provide adaptable Web service behavior depending on the service contract. In this paper, we propose two different approaches to increase adaptability of Web services and SOA. The first one is based on a technical solution which considers Aspect Oriented Programming (AOP) as a new design solution for Web services. We implemented an infrastructure to enrich services with aspects and to dynamically reroute messages according to changes, without redeployment. The second one combines Model Driven Development (MDD) and Context-Awareness to promote reusability and adaptability of Web services behavior depending on the service context.

Context Aware Management Plateform to Invoke Remote or Local e Learning Services: Application to Navigation and Fishing Simulator

Many companies aim to use Web services to integrate heterogeneous and /or remote application in SOA (service oriented architecture) contexts. The SaaS (Software as a Service) economical model allows to link service consumption and pricing. We aim to consider e learning as a set of services, hosted according to Cloud Computing techniques. Moreover, we are convinced some local or remote services may be invoked according to context and training orchestration may be dynamically adapted on run time. We developped a concrete industrial product development based on Web services and WComp plate form for adaptability.

Simulation-based Response-time Analysis of Composite Web Services

Service-oriented computing (SOC) strives for applications having services as the fundamental element of design, and Web services acting as the enabling technology. Web services use open, XML-based standards and are becoming the most important technology for communications between disparate applications in different enterprises. In this paper, the authors study end-to-end response time for synchronous and asynchronous composite Web services invoked over the Internet. The main aim is to study the queuing time and execution time for various classes of clients present in a system. the authors present a formal model based on queuing network to simulate the execution time for composite Web services, which require different blend of services and need different set of resources to execute.

Dynamically Adapting Clients to Web Services Changing

Web Services are the fitted technical solution which provides the required loose coupling to achieve Service Oriented Architecture (SOA). However, there is still much to be done in order to increase flexibility and adaptability to SOA-based applications. In previous researches, we proposed approaches based on Aspect Oriented Programming (AOP) and Process Algebra (PA) to address flexibility and client generation issues in the Web Service context. In this paper, we extend these works in order to automatically create extended BPEL processes and generate clients which dynamically adapt themselves to the service changing.

Enterprise 2.0: Research Challenges and Opportunities

Blending Web 2.0 technologies with enterprise information systems is setting up the stage for a new generation of information systems that will help enterprises open up new communication channels with their stakeholders. Contrary to traditional enterprises with top-down command flow and bottom-up feedback flow, the same flows in Enterprise 2.0 cross all levels and in all directions bringing people together in the development of creative and innovative ideas. The power of Web 2.0 technologies stems from their ability to capture real-world phenomena such as collaboration, competition, and partnership that can be converted into useful and structured information sources from which enterprises can draw information about markets’ trends, consumers’ habits, suppliers’ strategies, etc. This paper discusses the research efforts that our international research group has put into the topic of Enterprise 2.0 (aka Social Enterprise). In particular, our research group advocates that existing practices for managing enterprise information systems need to be re-visited in a way that permits to capture social relations that arise inside and outside the enterprise, to establish guidelines and techniques to assist IT practitioners integrate social relations into their design, development, and maintenance efforts of these information systems, and last but not least to identify and tackle challenges that prevent capturing social relations.

Towards Intelligent Collaborative Learning Simulations: Extending the IMS LD Standard by Web Semantic Based ITSs

Many research works had emphasized that successful learning processes can’t be achieved without established methods and standards, consistent learner support or also collaborative activities. Applying intelligent features to simulate collaborative behavior could bring new challenging issues in e-learning processes. In this paper, we propose a Semantic web based approach which extends the Instructional Management Systems Learning Design information model to take into account intelligent virtual roles required by Collaborative Learning processes.

Extending the IMS LD standard with Adaptability

A few e-Learning platforms propose a solution for ubiquity and context aware adaptability. We decided to propose a solution with meta modeling approach based on previous related works. We used a concrete software engineering industrial product that was promoted by French Government.