Java Portlet (JSR 286)

References

https://www.ibm.com/developerworks/cn/java/j-lo-jsr286-1/

http://www.ibm.com/developerworks/cn/java/j-lo-jsr286-2/

http://www.ibm.com/developerworks/cn/java/j-lo-jsr286-3/index.html

http://www.oracle.com/technetwork/java/jsr286-141866.html

http://www.theserverside.com/tutorial/JSR-286-development-tutorial-An-introduction-to-portlet-programming

Portlet Specification (JSR 286)

Overview

• web based components, rendered (fragment) within the confines of a portlet page

• enable integration between applications and portals

• portlet in two flavours:

  • provide small amount of functionality and then aggregated by portal server into larger application, or

  • whole application be written to reside in only one or a few portlet windows

Portlet interface

implements javax.portlet.Portlet interface

• in WAR, once loaded will not unload until server shutdown / explicitly take down

• life cycle methods:

  • init

  • destroy

  • processAction - to be used during action-processing phase

  • render

abstract class GenericPortlet - usually not implement interface but extend

• doDispatch - dispatches incoming requests to the appropriate method

  • doView

    • PortletRequest / PortletResponse

  • doEdit

  • doHelp

Packing

• in WAR

• web.xml: <web-app> <display-name>... <welcome-file-list>...

• WEB-INF/portlet.xml

  • name

  • display-name

  • portlet-class

  • supports

    • mime-type (text/html)

    • portlet-mode

  • portlet-info

    • title

  • default-namespace: http://portletbook/

• a single portlet application maps to one WAR and may have multiple portlets

Coordination between portlets

• Events

  • a life cycle operation, occurred before rendering

  • loosely coupled, brokered means of communication between portlets

  • portlet application defines event name in event-definition element

  • portlet declare events in deployment descriptor (event-definition), must be first defined in portlet application

    • to publish : supported-publishing-event

    • to process : supported-processing-event

  • QName (getQName()) - id uniquely

  • getName() - only local part of event name

  • wildcards and aliases available

• Public Render Parameters

  • public render parameters set in processAction() are available in render parameters of other portlets

  • simpler to use than events

  • portlet declare public render parameters in public-render-parameter element in portlet application section

  • portlet specify public render parameters to be shared in portlet section through supported-public-render-parameter, referencing the id of a public render parameter defined in portlet application section

Serving Resources

• Direct link to resource

  • good for static resource that is same to all portlets

• Resource service