Liferay Portlet:-

"Portlets are hot deployable small web applications that run in a portion of a web page and it is managed by portlet container". Portlets produce fragments of markup code that are aggregated into a portal page, not complete documents.


Portlet hierarchy:-

Portlet Specifications:-

There are following two types of specifications :-

Portlet Specification 1.0 (JSR168)

Portlet Specification 2.0 (JSR 286)

JSR 168 covers the basic portlet development but Java Community People was added more features and specification in JSR 286.

The following are important Specification and Features in JSR 286 :-

• Inter Portlet Communication

• Another State in Lifecycle

• Ajax Support

• Serving Resources

• Portlet Filter and Listeners

	JSR 168	JSR 286
1	ActionURL	ActionURL
	RenderURL	RenderURL
		ResourceURL
2	Window States	Window States
	(min)	(min)
	(max)	(max)
	(normal)	(normal)
3	Portlet Modes	Portlet Modes
	(view)	(view)
	(help)	(help)
	(edit)	(edit)
4		IPC (Inter Portlet Communication)

Introduction to Portlet Phases and Lifecycle Methods:-

Portlet performs unique operation in each lifecycle execution which are known as portlet phases. 

initially following two portlet phases are defined in JSR-168 (Portlet 1.0) specification :-

Render Phase

Action Phase

Later following twomore  portlet phases are added in JSR-286 (Portlet 2.0) specification:-

Event Phase

Resource Serving Phase

Lifecycle methods of Portlet:-

1)init()

This method will be called when portlet is deployed and instantiated by portlet container.

2)render()

This method will be called to render the content. Represent Render phase.

3)processAction()

This method will be called when any action performed.

4)processEvent()

This method will be called when any event is triggered.

5)serveResource()

This method will be called when any resource is served with resource URL.

6)destroy()

This method will be called when portlet is un-deployed by portlet container.

JSR 168 lifecycle :-
init() --> processAction() --> render() --> destroy()

JSR 286 Lifecycle for IPC Event:-
init() --> processAction() --> processEvent() --> render() --> destroy()


Note :- The serveResource() method can be used to implement Ajax call, by invoking the resource URL through the XMLHttpRequest(or XMLPortletRequest) in client-side JavaScript code.

Liferay Portlet Modes:-

 mainly liferay containing 3 types of modes
  1.VIEW   2.EDIT   3.HELP

  In additional to it Liferay contains 6 other modes
  1.About   2. Config   3. Preview    4.Print    5.Edit Defaults    6.Edit Guests

Liferay Portlet URLs:-

1. Render URL (which is portlet URL and responsible for rendering of the portlet and method doView() is executed)

2. Action URL (which is also portlet URL and responsible for performing some action with page reload and method processAction() is executed, and is followed by renderRequest)

3. Resource URL (which is responsible for performing some action without page reload i.e. Ajax and method serveResource() is executed and is NOT followed by render request. Resource Serving was not available in JSR168 but its avaible in JSR286.

Window state:- The liferay window state are Normal, Maximized , minimized and pop_up.