Model-driven and Compositional Service Creation in the Internet of Services

Doktorgradsavhandling i informasjons- og kommunikasjonsteknologi, Universitetet i Agder, Grimstad, 2012In the Future Internet, billions of devices will be connected to the Internet. Devices at any levels of hierarchy provide software functionality that can be used by others. We can call the device’s functionality a service, which in turn, introduces the concept of the Internet of Services. From the software developer perspectives, a new service can be created by utilizing services in the Internet of Services. An important issue of the creation of such service-based application is regarding their deployment method on personalized and embedded devices. For each device with different capability and configuration, different tailored code is required. For this, a flexible method and tools that support an automatic code generation for a device with a specific capability and configuration are mandatory. This thesis proposes PMG-pro (Present, Model, Generate and provide), a language- independent, bottom-up and model-driven method for the service creation in the Internet of Services. With this method, a service is created by providing the new functionality of a service-based application as a service. By using existing service frameworks and APIs, from a service description, PMG-pro generates an abstract graphical service representation (service model) and source code implementing for service invocations. Depending on the target modeling languages, different graphical notations can be used to represent services. Similarly, different programming languages can also be used to implement the service invocations. We call these pairs (i.e., the service model and the source code) platform-specific models. With these platform models, service composers use the graphical service representation to model new service-based applications, while the machine (i.e., computer system) uses the source code to generate code from the service-based application model. This thesis contributes to the service engineering method that applies a modeldriven development approach. Three main contributions are a model-driven method for service creation, an automatic service presentation of pre-made services, and a new method of handling device capability and configuration. With these, service creation in the Internet of Services can be done in a rapid and automatic manner. Service designers can create a new service by defining a model of service-based applications using pre-made service models, while code for a specific device can be generated automatically from the model. The PMG-pro method has been partly prototyped and validated on various case studies in the domain of smart homes that have produced encouraging results. The method promotes a rapid, language-independent, and unified process of software service development

A JINI FRAMEWORK FOR DISTRIBUTED SERVICE FLEXIBILITY

Existing distributed middleware technologies and Enterprise Application frameworks lack in support to service flexibility from both the developer's and user's point of view. In this paper we propose a JINI-based framework, namely PRINCEPS (Pluggable Reliable Infrastructure for Network Computing and Enhanced Properties of Service), which provides a distributed and dynamic environment for flexible service provision. We claim that the adoption of JINI makes it possible to dramatically improve service flexibility by federating services in a dynamic and self-healing networked community. The framework provides the clients with a (web-based) mechanism for selecting services according to functional requirements (i.e., the service interface)and non-functional requirements (the quality of service, i.e., reliability, performance). More implementations of the same service can coexist in the framework, each of one satisfying different non-functional requirements. PRINCEPS provides service substitutability at various levels. In fact, any kind of service can be plugged in PRINCEPS: CORBA-based services, socket-based services, and centralized services. PRINCEPS also supports service developers with its own mechanism to integrate existing services. Preliminary performance experiments and lessons learned from the PRINCEPS prototype are also discussed

A Jini Framework for Distributed Service Flexibility

Existing distributed middleware technologies and Enterprise Application frameworks lack in support to service flexibility from both the developer's and user's point of view. In this paper we propose a JINI-based framework, namely PRINCEPS (Pluggable Reliable Infrastructure for Network Computing and Enhanced Properties of Service), which provides a distributed and dynamic environment for flexible service provision. We claim that the adoption of JINI makes it possible to dramatically improve service flexibility by federating services in a dynamic and self-healing networked community. The framework provides the clients with a (web-based) mechanism for selecting services according to functional requirements (i.e., the service interface)and non-functional requirements (the quality of service, i.e., reliability, performance). More implementations of the same service can coexist in the framework, each of one satisfying different non-functional requirements. PRINCEPS provides service substitutability at various levels. In fact, any kind of service can be plugged in PRINCEPS: CORBA-based services, socket-based services, and centralized services. PRINCEPS also supports service developers with its own mechanism to integrate existing services. Preliminary performance experiments and lessons learned from the PRINCEPS prototype are also discussed