Equinox outline [note]

Equinox

L an osgi R4 specification implementation

L involve: osgi framework implement, osgi standard service bundles implementation, osgi server-side app (J2EE), equinox deployment framework

 

Modularity

L objective: Changes in on part of a system shoshould not lead to unexpected behavior in other parts

L we need to be able to share classes and resource between bundles (modules), two main ways: require-bundle & Import-Package

 

Require-bundle

L gain access to all packages exported by another bundle

L tight coupling

Import-Package

L import specific packages

L loose coupling

 

Best practices: modularity

L import-package is recommended

L require-bundles used for complex scenarios

 

Collaboration

Inter bundle collaboration:

L extension Registry

L Service Registry

L declarative services (build upon the Service Registry)

 

Extension Registry

L a Per extension point list of contributed extensions

L private context

L tightly coupled model

L declarative: plugin. xml

L lazy loading

L life cycle scope: resolved state of bundle

L no security to control

 

Service Registry

L pblish/discover/Bind Model

L public context

L Loosely Coupled Model

L API based, non declarative

L eager Loading

L life cycle scope: started state of bundle

L permissions to control

 

Declarative services

L build upon service registry

L adds a declarative mechanic

L simplified programming model: pojo with dependency injection (IOC)

L lazy loading

L lifecycle managed by central Runtime

Best practices: Collaboration

L extension Registry: tightly coupled relationship

L declarative services: loosely coupled relationship (recommended)

L Service Registry: Same as declarative services, unless have a complex need