Step by Step Tutorial of OSGI- Chapter 1


OSGI is a very existing technology, it provides an open common architecture for service providers, developers, software vendors. It provides an general-purpose, secure and managed framework that support the deployment of extensible and downloadable applications called BUNDLES

Bundles are like plugins. A developer can extend the framework to his wildest dreams by making bundle and installing into the framework.
Bundle are small applications or service which can be used and can be removed when not required.

A the lifecyle of bundles are managed by framework.

The functionality of framework is divided into for four important layers

Security layer
Module Layer
Life Cycle Layer
Actual Service.

Brief Description of each layer is mentioned below. We will not going to dive deep into layers in this post of the tutorial.
Of-course we will learn the layers in coming post while we are coding as well.
Reading is all good but unless and until we will not get our hands dirty with we will not learn properly.

Ok Lets get down to brief description of layers.

Module Layer.

It defines the modularization modal of java. Module a.k.a bundles have to follow strict rules for sharing java packages between each other. For example only providing the api interfaces available to other bundle while hiding the implementation.

Lets say module layer holds bundles which can be treated as tiny applications running inside the framework

Life Cycle layer.

This layer define how bundles are started and stopped as well as how bundles are installed, updated, and uninstalled.

Service layer.

As the name specifies service layer is responsible for service provided by bundles. it simplifies the development and deployment of service bundles by de-coupling the service's specification(java interface) and its implementation.
This layers allows developer to hide the actual implementation and only provide the interface to use the service provided by bundles.

By the way we are also going to create a little project while we will be learning the OSGI concepts. Excited ? I know me too.
Actually I wanted to create a group to learn with us. I mean couple of people learning together so that we can discuss and have a creative conversation about it.

Next part of tutorial we will discuss about the Module layer necessary to make us start coding while understanding the concept.

Are you in ? Drop me a comment..Lets get this Tutorial started :)

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