Using Eclipse to develop bundle applications based on OSGi

The Open Service Gateway Protocol (Open Services Gateways Initiative), referred to as OSGi, defines a standard, service-oriented computing environment for network services, and provides users with an open, service-oriented component, easily deployable programming model, This programming model allows users to bind well-defined interface specifications to specific services in an OSGI runtime environment, and OSGi technology is playing an increasingly important role in the process of component SOA service-centric enterprise applications. In this article, you will introduce the concept and architecture of OSGi and develop a service application Bundle based on OSGi specification using Eclipse 3.2. By learning this article, readers can learn how to develop and deploy Bundle applications based on OSGi specifications.

Introduction to OSGI Specification

The OSGi Consortium, founded in 1999, is a non-profit organization designed to create an open service specification. The OSGI specification defines a standard, component-oriented computing environment for network services, and its original purpose is to provide a common software operating platform for various embedded devices, a middleware platform that distinguishes between device operating systems and hardware, through which applications can be provided to different software providers (OSGi is called Bundle) The ability to perform component lifecycle management, such as where application components can be installed, upgraded, or removed from running without disrupting device operations, and application components can dynamically discover and use other libraries or applications. Because OSGi technology has the advantages of modularization and dynamic loading application of service components, it is being paid more and more attention to, such as embedded equipment manufacturing, automobile manufacturing, enterprise application and so on. Currently, the OSGi Federation publishes the latest OSGi service specification of 4.0, and readers can refer to the resources for more information.

OSGi Architecture

The OSGi architecture is a plug-in software architecture that includes an OSGI framework and a series of Plug-ins, in which Plug-ins are called Bundle, where the OSGi framework specification is a central part of the OSGi specification, providing a common, secure, manageable Java framework through which to can support deployment and extension of Bundle service applications. Java classes can be shared between Bundle through the Import Package and Require-bundle, and in the OSGi service platform, users develop Bundle to provide the functionality they need, which can be dynamically loaded and unloaded, or remotely under demand Load and upgrade. The OSGi architecture diagram is shown in Figure 1:

Diagram 1 OSGi architecture

which

Execution Environment:

Bundle applications rely on running Java execution environments, such as j2se-1.4, CDC-1.0, and so on, that are available execution environments.