Nuxeo EP 5
Open Source
Enterprise Content Management
A Seam Case Study
Thierry Delprat, CTO
tdelprat@nuxeo.com

Agenda
• What is Nuxeo 5?
– Architecture overview
• Nuxeo 5 EP
– Challenges and requirements of the Web UI front-end
• Nuxeo 5 and Seam
– How we use Seam to build Nuxeo 5 EP
2

Nuxeo 5 – Solution Overview
• An Open Source ECM solution
– EDM, WF/BPM, Collaboration, WCM ...
• A platform for building custom ECM solutions
– Generic services with an « extension and customization » model
– A framework for building ECM applications
• The Java 5 version of CPS 3.4
– Keep the proven concepts of Zope/CPS (2000 -> 2006)
– Leverage the Java 5 infrastructure
• A multi-platform and multi-target ECM solution
– Thin client: Java EE Web application – Nuxeo 5 EP
– Rich client: Eclipse RCP application – Nuxeo 5 RCP
– Client/Server: RCP client with JEE server
3

Nuxeo 5 – Architecture Overview
• Core Layer: Embeddable document repository
– Storage-oriented services + plugin model
– Repository API: POJO and ejb3
• Service Layer: a extensible set of ECM services
– Generic and con gurable services + extension model
– Services API: POJO and ejb3
• Client Layer: UI management
– Links services together to achieve business speci c needs
– Uses Services Layer and Core Layer API
– Clients can be
• Web application
• RCP Application
• Flex client
4

Nuxeo 5 – « 10 000 feet view »
Audit Service Nuxeo Core
Query Management
Web Application
WF and BPM Service
LifeCycle Management
EJB EJB
Relation Service Security Management
APIs
APIs
Versions management
RCP Application Transformation Service
Schemas Management
POJO
POJO
Directory Service
Nuxeo Core
(Content Repository)
Flex Application Indexation Service
Storage adapter
JCR/Jackrabbit
NXRuntime
JBoss (JMX) or Eclipse RCP (OSGi)
5

Nuxeo 5 EP - Web UI
The web client on top of Nuxeo 5 EP services
What are the requirements
Why we choose JSF and JBoss Seam
6

Requirements > Generation engine
• Powerful templating system
– Want to keep a templating engine with a composition system
• MVC model, Widget and Layout system
– Clear separation of concerns (Presentation / Validation / Model)
– Reusable and customizable widgets (like in CPS)
– Complete layout system like with CPSSkins
• Not tied to HTML
– Keep the possibility to generate non HTML data (ie : XForm)
7

Requirements > Why JSF & Facelets?
• Great standard even if complex
– Java EE Standard
– Very pluggable and extensible
(EL Binding, Layout and Theme manager)
• Growing libraries of Widgets
– from Ajax/HTML to DataModel
• IDE support is growing
• Facelets are close to Zope's PageTemplates (ZPT)
– Templating and slot model
– Pure presentation technology
– Clean for designers
8

Requirements > Web Framework
• JSF and Facelets compliant
• Cache aware state management
– Each page rendering needs to fetch a lot of documents
➡But most documents are the same between two requests
keep state of the user context
– Data needs to be fresh and invalidated
• Remote access to application’s controlers
– Access via Ajax
– Access via Browser helper
– Access via O ce Plugin
9

Requirements > Web Framework
• Seamless EJB3 integration
– Easy access to EJB3 Nuxeo EP Services
– JSF binding
• Loosely coupled UI and application components
– Nuxeo 5 must provide hot-pluggable Web components
• Shared context
• Dependencies injections
• Events system
• Multiscreen and wizards management
– ECM provides a lot of use cases
– Manual page ow management is boring
10

Nuxeo 5 Web Framework > Why Seam ?
• Seam provides a lot of the needed features “out of the box”
– Native EJB3 integration
– Bijection
– Seam context management
– Seam remoting and Ajax4JSF integration
– Page ows via JBPM integration
• Good t with other selected infrastructure components
– JBoss AS, jBPM and JSF
• Great project! :-)
– Good references of Seam’s lead developers
– The right vision for a web framework
• New, modern and evolving framework
11

Nuxeo 5 and Seam
How we use Seam in Nuxeo 5 EP
12

Nuxeo 5 & Seam > Context Management
Usage
• Partial content location tree => Seam context
Server
– Read placeful con guration Users
Domain Documents
• UI Theme & Perspective con guration
Workspace Theme
• User Noti cation
– Retrieve data to display Current Document
Children
• Current working context => Seam context
– Current document and children Shared Context
– Clipboard (cut/copy/paste) MySelection
– Working set of documents
• Easy mass document management Clipboard
13

Nuxeo 5 & Seam > Context Management
Content
• Seam context stores Document and lists of documents
– DocumentModel is an artifact for a document and associated
con guration
• Lazy data fetching from the core
• Lazy placeful con guration fetching
– Services may contribute new facet of contextual data
• Security descriptors, Relations informations, Subscription con guration, ...
• Context variable are usually pulled via factory
– Use of the Seam @Factory annotation
– Use of @DataModel annotation to feed DataLists from context
• Each component can access easily the contextual documents
– Ask for injection via @In
14

Nuxeo 5 & Seam > Context Management
Injection & Outjection
• Services get the current document by injection (AL base class)
public abstract class InputController{
@In(required = true)
protected ECServer ecServer;
@In(required = true)
protected ECDomain ecDomain;
@In(required = true)
protected ECContentRoot ecContentRoot;
@In(required = false)
protected DocumentModel currentItem;
• Navigation controlers outject the currentDocument
current children
Factory
Navigation tree
Current security info
Factory
Breadcrumb Document
Actions
Actions relations info
Actions Factory
Actions
15

Nuxeo 5 & Seam > Context Management
Events and Invalidation
• Context Invalidation
– Dependent context variables
update currentDocument => update currentDocumentChilds
– Invalidation needs to
• nullify the variable to get @Factory called the next time (lazy refresh)
• call explicitly the factory
– Dependencies are spread across components that don't know each
others (distributed invalidation needed)
• Seam messaging system is used to propagate context changes
Events.instance().raiseEvent(EventNames.DOCUMENT_SELECTION_CHANGED);
Component A
@Observer( { EventNames.DOCUMENT_SELECTION_CHANGED, Component B
EventNames.CONTENT_ROOT_CHILD_SELECTION_CHANGED,
EventNames.DOCUMENT_CHANGED })
@Factory("documentResource")
public void getDocumentResource() {
documentResource = relationManager.getQNameResource(documentNamespace,
currentItem);
}
16

Nuxeo 5 & Seam > Context Management
Caching
• “Stalled copies” problem
– Long running contexts act as a cache (session/conversation)
• invalidation needs to be propagated when changes occur
(document edit, security update, new child ...)
– There may be a lots of users using the same document
• e cient to share the state of a document across user's contexts
(Domain, Workspace, Folders, etc.)
• Nuxeo 5 Cache and Context management
– The documents are actually stored in JBoss cache
• Cache is invalidated by core events
– The context holds GhostDocumentModels or lists of Ghosts
• acts as transparent stubs to the real DocumentModel in the shared cache
17

Nuxeo 5 & Seam > Context Management
Conversation
• Nuxeo 5 uses nested conversations
– Wizards
– Temporary state management
• The Seam Workspace Management is useful for Nuxeo 5
– like opening several File Explorers is parallel
• Nuxeo 5 will use long running conversations
– Parallel sessions that holds the navigation context
– Use Seam Workspace Management to switch between contexts
18

Nuxeo 5 & Seam
JSF Limitations
• JSF is a powerful UI model, but...
– urls are not meaningful
– open in new tab/window is broken by JS form submission !
– EL does not permit to send parameters
• Nuxeo 5 needs meaningful urls
– Accessibility and WCM
– Bookmark a Document
– Send a link to a document via Mail
• Seam provides a helper for these problems
– Integrate GET requests with JSF and Context
– Bind requests parameters
– Used by Nuxeo 5 to generate 'PermLink' for the documents
– EL enhancements in latest Seam
19

Nuxeo 5 & Seam
jBPM Integration > Page ow
• In ECM creation wizard are useful
– Fill out all the properties of the complex document
– Let user de ne di erent options during the creation process
• Choose templates during the creation process
• Assign roles to users
– Optional ”step by step” interactive help
• Nuxeo 5 uses Page ow for wizard
– Complex screens series can be easily modelized
– Make the application « agile » to t customer needs
– Temporary state is easily handled by the Seam context
20

Nuxeo 5 & Seam
Integrated Remoting
• Some Nuxeo 5 Seam Components are accessed remotely
– ActionListener
– Speci c Seam Components
• By some PlugIns like LiveEdit
– Use SOAP to integrate Nuxeo5 with MS O ce and OpenO ce
• By the browser helpers (Firefox and IE)
– Use Seam remoting to upload les by Drag&Drop
• The theme Editor
– Uses Seam remoting to edit the theme from AJAX WYSIWYG editor
• Will be used for internal Drag&Drop and AJAX features
– When Nuxeo 5 is aligned with latest Seam release (1.1)
21

Nuxeo 5 & Seam
Integrated Remoting > Examples
Drag & Drop Drag & Drop les from the Desktop to the Browser
ScreenCast Great User Experience for le upload!
Firefox / Internet Explorer
Win32 / MacOS / Linux
Nuxeo Theme Editor
Modify page layout from the browser using AJAX
Add page fragments visually
Basically: a WYSYWG UI editor for JSF web apps
22

Nuxeo 5 & Seam
Additional Views and Actions
NXRelations
NXAudit
Contributed Views
NXWork ow
23

Nuxeo 5 & Seam
Loosely coupled components
• The Nuxeo 5 UI is build from several components
– Base components (DocumentManager, SecurityManager ...)
– Additional optional components
• NXAuditClient
• NXRelationClient
• NXWork owClient
• etc.
• Each additional component uses NXRuntime extension points
– to contribute Views
• Facelets that provide a new view on Documents: AuditView, RelationView,
TaskView, etc.
– to contribute Action
• Buttons or Links to achieve additional processing: Add a relation,
Add a comment, Create a new folder, etc.
24

Nuxeo 5 & Seam
Loosely coupled components
• Components share some state via the context
– At least the currentDocument
– Most ActionListers use @In to get some contextual documents
• Components may notify each other
– Usage of the @Observer to become an event listener
• New components may be easily added
– Only cares about the shared data and events
• not “who” the other components are
– New views can be added transparently
25

Nuxeo 5 & Seam
Factory for EJB3
• Each action listener needs to access one or more services of
Nuxeo’s platform
• Services are accessed via a Delegate Layer
– Wraps remote or local calls
• Delegates use the Seam component manager pattern
– use @Unwrap to access services via a transparent Factory
• Base components are created at application start-up
– use @Startup to load services automatically
• Base class of Action Listener provide compulsory services
– contains @In to get all basic services
26

Nuxeo 5 & Seam
Components interactions
@In / @Out / @Factory @Unwrap
Delegate
Facelet Action Listener
Facelet Platform service
Facelet (Seam Component)
(Seam Component)
Seam Seam Context
NXAction Jboss Cache
Events Conversation / Session NXCore events
update / invalidate
@Unwrap
@In / @Out / @Factory
Facelet Delegate
Action Listener
Facelet
Facelet Platform service
(Seam Component)
(Seam Component)
27

Nuxeo 5 & Seam > Conclusion
• Seam
– Provides a nice infrastructure for Nuxeo 5 web application
– Helped us building Nuxeo 5 in a few months
• Provides a great pluggable component model for the web layer
– Easily de ne new ECM Actions
• A lot of good perspectives
– Align on Seam 1.1 in the next days
– Leverage Seam and Ajax4JSF integration
– Leverage Workspace Management
– Leverage integration between
• NXWork ow (JBPM based)
• Seam Business Process Context
28

ank you!
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