1. Overall Architecture and Component Model
Nuxeo Platform
Overall Architecture and Component Model

2. Nuxeo Platform
A highly customizable and extensible content management platform for building business applications
Bundled Architecture
Deploy only the required bundles
Develop and add custom plug-ins
Deploy on multiple servers
Deploy on multiple infrastructures
As a standalone
Within Junit System
On Tomcat Server
Connect to various persistence stores
SQL Database
LDAP and NoSQL Databases
Filesystem Storage

3. Architecture Content Repository Content Automation REST API
Persistence, query, versioning and access control of documents
Handles Documents: Files, meta-data and any structured data
Integrated with Elastic Search and MangoDB
Content Automation
Exposes common Nuxeo actions as atomic operations
Can be assembled to orchestrate complex business rules and logic
REST API
Exposes common Nuxeo resources
Workflow Engine
Built on repository and automation, as a graph
Typically developed using Nuxeo Studio
Support for UI Frameworks
JSF/SEAM, HTML5/JavaScript, Portal Technologies and etc.,

4. Bundle Based Component Model
Nuxeo Bundle
A pluggable JAR with an OSGI dependency manifest
Everything in Nuxeo is packaged as a bundle
May contain one or more components, services and extension points
Component
A software object declared via XML
Primarily to expose a service
Service
A software object that can be registered, discovered, listed and accessed
Extension Point
Entry-point for services to inject customization
To configure or extend a service or a component

5. OSGi Bundle Concepts
A OSGi Bundle is a JAR with META-INF/MANIFEST.MF with OSGi headers
Some of the important headers
Bundle-SymbolicName
Bundle-Version: mahor.minor.patch-<TAG>
Export-Package: List of packages whose classes are made visible to others
Import-Package: List of packages to be discovered from exporting bundles
Verions Selection: Example: [1.2.0, 1.3.0)
JDK Classes are always visible for every-one
Bundle-Activator: Bootstrap class that do housekeeping for the bundle
Bundle-ActivationPolicy: Activates the bundle only when a class is loaded from it
Require-Bundle: For split-bundles
Fragment-Host: For optional features/resources/etc.,
Bundle-RequiredExecutionEnvironment: JRE
Bundle-Classpath: Internal classpath of the bundle
Service-Component: For declaring components via declarative services

6. OSGi Bundle Concepts Bundles are stateful objects The State Life-cycle
Installed: Bundle is deployed in the OSGi Container
Resolved: Bundle dependencies are successfully resolved
Delegates to JRE class-loader for java.* or javax.* classes. Stops on fail.
Delegates to exporting class-loader. Stops on fail.
Delegates to requiring-bundle class-loader. Continues on fail.
Delegates to host & fragment-bundle class-loader. Stops on fail.
Searches the own classpath
Starting: Bundle is running Activator to start the bundle
Stopping: Bundle is now ready for exposing/using other bundles/services/components
Active: Bundle is running the Activator to shutdown the bundle
Uninstalled: Bundle is un-deployed from the container

7. OSGi Bundle Concepts OSGI Compendium Services Declarative Services
Service Registry
Builds an SOA within JVM
Services register them selves (typically in the activators)
Service Locator publishes the services
Clients discover the services
EventAdmin Services
A system service for asynchronous communication among components
Config Management Services
A system service to reconfigure the components without restart
Declarative Services
An approach to build services using POJOs, normally using Spring IoC
Nuxeo offers API for service discovery
Framework.getService(<T>)

8. Contributing to Extension
You have a maven project
Develop the contribution
Locate the folder src/main/resources/OSGI-INF
Create a contribution file
Probably named as myproject-target-service-contribution.xml
Declare a component in the contribution file
<component name=“unique.name”>
<extension target=“existing.service.name”>
<!– extensions -- >
</extension>
</component>
Declare the contribution in the bundle
Locate the file src/main/resources/META-INF/MANIFEST.MF
Add/update the header Nuxeo-Component by providing the contribution xml file name

9. Bundle Deployment Process
Nuxeo Deployment Process is incremental involving phases
Template Processing
Reads templates and generates configurations
Configuration may include data source settings, SMTP settings and etc.,
Profile system for quick configuration
Deployment Fragment Preprocessor
The target WEB application acts as a host for several fragment bundles
Typically used for mutually exclusive resource bundles
Fragments may provide i18n, WAR resources and etc.,
Bundle Deployment
Actual OSGI deployment
Activates bundles
WAR Deployment
Web Resource Declaration

10. Adding a New Feature
A new feature addition usually comprises of several bundles
Core Contrib Bundle
With direct contributions to the repository
Document Types, Listeners, Security Policies
Core Bundle
POJO implementations of components and services
Façade Bundle
With JEE Bindings
JTA, Remoting, JAAS, Transactions
API Bundle
Service API Interfaces and remotable DTO objects
Client Bundles
Views and Actions