Introducing Portlet

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Introducing Portlet

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Content

• 1?Portal and Portal Server
• 2?Jetspeed Structure
• 3?Portlet
• 4?Portlet in Jetspeed
• 5?Conclusion

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1?Portal and Portal Server
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What Are Portals ?

• Portals provide a secure, single point of
  interaction with diverse information, business
  processes, and people, personalized to a user's
  needs and responsibilities." There is a good
  analogy between what portals add to web
  applications and what window managers (like
  Microsoft windows) add to operating systems (like
  DOS). Both provide a consistent and uniform way
  to interact with applications.

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What Are Portlets?

• Portlets, are "visible active components users
  see within their portal pages... In the simplest
  terms, a portlet is a java servlet that operates
  inside a portal."

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An Example

• See next figure for an example portal page with
  two visible components on it. Each visible
  component is called a portlet. In this example,
  one portlet allows the user to go to a URL the
  other portlet provides some reminder text to the
  user.

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Portal Server

• A portal server provides common services such as
  application connectivity, integration,
  administration, and presentation that would be
  required across all portal environments.
  Functionally, a portal server serves the portlets
  to the user.

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The Portal Servers

• 1?IBMs WebSphere Portal Server
• 2?Apaches Jetspeed
• 3?Metadots Portal Server
• 4?Sun Java System Portal Server
• 5?MSs SharePoint Portal Server
• And so on.

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WebSphere Portal Server

• WedSphere portal basic structure provides some
  service that can easily interact with others
  ,flow ,enterprise application ,the content from
  the syndicated content provider ,database and
  information which is structured or non-structured.

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Jetspeed

• Jetspeed is an open source implementation of an
  enterprise information portal, using java and
  XML. Jetspeed acts as the central hub where
  information from multiple sources are made
  available in an easy to use manner.

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Metadot Portal Server

• Metadot is a popular open source portal software
  (GPL) recognized for its revolutionary
  ease-of-use. It provides content management like
  file, page and link management, collaboration
  features like discussion forums and polls and
  personalization like my yahoo

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Sun Portal Server

• It provides all the user, policy and identity
  management to enforce the security, single sign
  on and access capabilities to end user
  communities

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MS SharePoint

• SharePoint allows information workers to create
  powerful personalized interfaces by simply
  dragging and dropping pre-defined Web Part
  Components.
• It is implemented by .net technology

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2?Jetspeed architecture
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• Jetspeed, written in java language, Jetspeed
  offers a portal API for developing portlets,
  small java applications that are building blocks
  of a portal. Jetspeed makes connections to
  external data and content feeds to retrieve and
  display the data via a portal. You can implement
  the portal and access it from a web browser or a
  wireless device (such as a WAP phone or palm
  device). Jetspeed supports built-in services for
  user interface customization, caching,
  persistence, and user authentication, eliminating
  the need implement these services.

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Jetspeed Architecture Model

• This figure in next page illustrates the Jetspeed
  architecture model. Jetspeed is built on top of
  Turbine, a servlet-based framework. Turbine
  handles user authentication and page layout as
  well as scheduling. Jetspeed can run on a number
  of servlet engines and databases.

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High-level Jetspeed Features

• Support for wireless markup language (WML)
• A web application development infrastructure
• Portability across all platforms that support JDK
  1.2 and Servlet 2.2
• User, group, role, and permission administration
  via security portlets
• Role-based security access to portlets

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Page Layout

• This next figure illustrates the anatomy of a
  page containing portlets. Within a page, portlet
  content gets rendered by a PortletControl and a
  PortletController.

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• PortletControl the function of the
  PortletControl within the Portlet page handles
  rendering the title and body of the Portlet.

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• PortletController the function of the
  PortletController is to handle multiple
  PortletControls (each controlling a Portlet) to
  provide an entire page of information from all
  the Portlets.

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How Portlets Display Content

• To display content, portlets use the element
  construction set (ECS) API. This comes bundled
  with Jetspeed, which generates markup elements
  from java objects. You can use a servlet template
  or JSP technology to generate content as an
  output, which is then captured by an ECS element
  that displays the content. ECS supports WML as
  well as HTML and XML.

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What Is ECS?

• The Element Construction Set is a java API for
  generating elements for various markup languages
  it directly supports HTML 4.0 and XML, but can
  easily be extended to create tags for any markup
  language. It allows you to use java objects to
  generate markup code

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A Simple ecs Example

• Html html new Html()
• .addElement(new Head()
• .addElement(new Title("Demo")))
• .addElement(new Body()
• .addElement(new H1("Demo Header")))
• out.println(html.toString())
• output(out)

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Generate the Code Below

• lthtmlgt
• ltheadgtlttitlegtDemolt/titlegtlt/headgt
• ltbodygt
• lth1gtDemoHeaderlt/h1gt
• lt/bodygt
• lt/htmlgt

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• ECS places mark-up information into compiled
  code . Therefore, we generally recommend using a
  page template mechanism of your choice, rather
  than using ECS directly.

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Portlet Caching

• Jetspeed provides developers with an advanced
  caching mechanism. Portlets that need to be
  cached are placed within the cache with relevant
  handle information like the classname and some
  portlet configuration information like the URL,
  etc. If there is a need to remove the portlet
  from the cache, it can be done by providing an
  expire() method, which determines when the
  portlet needs to expire itself.

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What Are the Standard Portlets?

• HTML portlet
• JSP portlet
• RSS portlet
• Webpage portlet

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Wireless Support From portlets

• Jetspeed supports WAP devices, and the WAP
  browser renders WML content., One can uses RSS to
  syndicate content from the web site. The other
  can works with a local RSS-formatted XML file.

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3?Portlet
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• Depicts a portal's basic architecture. The
  portal web application processes the client
  request, retrieves the portlets on the user's
  current page, and then calls the portlet
  container to retrieve each portlet's content. The
  portlet container provides the runtime
  environment for the portlets and calls the
  portlets via the Portlet API. The portlet
  container is called from the portal via the
  Portlet invoker API The container retrieves
  information about the portal using the Portlet
  provider SPI (service provider interface).

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Page

• Depicts the basic portal page components. The
  portal page itself represents a complete markup
  document and aggregates several portlet windows.
  In addition to the portlets, the page may also
  consist of navigation areas and banners. A
  portlet window consists of a title bar with the
  portlet's title, decorations, and the content
  produced by the portlet..

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Portlet Container

• A portlet container runs portlets and provides
  them with the required runtime environment. A
  portlet container contains portlets and manages
  their life cycles. It also provides persistent
  storage mechanisms for the portlet preferences. A
  portlet container receives requests from the
  portal to execute requests on the portlets hosted
  by it. A portlet container is not responsible for
  aggregating the content produced by the portlets
  the portal itself handles aggregation.

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Portlet life cycle

• Init initialize the portlet and put the portlet
  into service
• Handle requests process different kinds of
  action- and render-requests
• Destroy put portlet out of service

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Portlet interface

• init(PortletConfig config)
• processAction(ActionRequest request,
  ActionResponse response)
• render(RenderRequest request, RenderResponse
  response)
• destroy()

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Portlet modes

• Required modes
• Optional custom modes
• Portal vendor-specific modes

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Window states

• Normal
• Maximized
• Minimized

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Persistent store

• The portlet can store persistent data for a
  specific user by using the PortletPreferences
  object. Preferences can be read and written in
  the action phase, and read in the render phase.

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Sessions

• JSR (java specification request
• ) 168's session concept is based on the
  HttpSession defined for web applications. As
  portlet applications are web applications, they
  use the same session as servlets.

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Including servlets/JSP pages

• In JSR 168, the include mechanism for servlets
  and JSP pages is the same for the Servlet API.
  Via the portlet context, a request dispatcher is
  retrieved for a given path The include() method
  is then called on this request-dispatcher object
  

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• PortletRequestDispatcher rd getPortletContext().
  getRequestDispatcher(editJSP)  
  Rd.include(portletRequest, portletResponse)
• But in jetspeed ,there are another method to
  include the servlets/jsp page.

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Advanced Portlet API Items

• User information
• Portal context
• Localization
• Caching

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Extensibility

• If a portlet application uses additional
  portlet modes or window states than the ones
  defined by the Portlet specification, the portlet
  application can declare them in the deployment
  descriptor.

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4?Portlet in Jetspeed
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What Is a Portlet?
A portlet is a web component managed by a
container, that generates dynamic content.
Portlets are platform independent Java classes
compiled to an architecture neutral bytecode that
can be loaded dynamically into and run by a web
server. While servlets usually interact directly
with web clients, portlets interact with web
clients indirectly through portals, via a request
response paradigm implemented by the portlet
container (HTTP). Portlets are specialized
servlets that plug into and run in portals.
Portlets are designed to be aggregatable in the
larger context of a portal page. They rely on the
portal infrastructure to function.
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Portal Architecture
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Aggregating Content
Portlets are invoked in the course of handling a
single request, aggregating their respective
produced content in one page by appending each
individual portlets output to the page. Portlets
generate markup fragments that can be aggregated
in the scope of a portal, containing links,
actions and content suitable for aggregation
within a portal.
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Portlet Modes

• View Mode standard user interaction
• Customize (Edit) Mode editing the portlet
  data, customizing the portlet content.
• Maximize View the portlet in full screen with
  no other portlets in view.
• Minimize Only show the Title Bar.
• Closed Close the portlet remove it from the
  page.
• When in View Mode, you can see that the title bar
  contains buttons allowing you to switch modes

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View Mode
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• Customize
• Close
• Minimize
• Maximize

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Portlet Customize Mode
Here is an example of an RSS Portlets
customization.
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PSML

• PSML is an acronym for Portal Structure Markup
  Language. It was created to allow content
  structure and abstraction within Jetspeed. PSML
  is XML, and is defined by an XML schema at
  http//xml.apache.org/jetspeed/2000/psml
• The layout of a portal page is defined in PSML.
  With PSML, you can define
• Which portlets will appear in your portal page,
  and at which position in the portal window.
• The look and feel (Skins) of the portal windows
• The layout (controller) strategies (2 column, 3
  column, tabbed-panes, menu-panes, single column)
  for collection of portlets
• The control, a decoration to apply to
  collections of portlets (title bars, borders,
  buttons in the title bar, tabs, menus)

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The Customizer
The layout (PSML) can be edited with the Jetspeed
Customizer (easier than editing XML). To
customize the current pane, press the pencil icon
in the title bar
Or you can also customize for a specific media
type

• Customizing allows you to
• Add and Remove portlets
• Move a portlet to a different position
• Choose the Skin to apply to this pane
• Choose the Layout to apply to this pane
• Change the name of the pane
• Add/Remove/Move Panes (only for Menu and Tab
  panes, which contain other panes).

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Adding a Portlet
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Moving and Removing Portlets

• Remove the portlet
• Move the portlet UP
• Move the portlet DOWN
• Move the portlet RIGHT
• Move the portlet LEFT

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Changing the Skin
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Layouts

• Menu-Pane
• Single Column
• Single Row
• Tabbed-Pane
• 3 Column (25/50/25)
• 3 Column (33/33/33)
• 2 Column (25/75)
• 2 Column (50/50)
• 2 Column (75/25)

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Changing The Layout
From 2 column to 3 column (33/33/33)
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Panes
Panes are collections of portlets specified
directly with either a Menu-pane layout or a
Tab-pane layout. Panes allow you to overlay
collections of portlets on top of the same screen
area. You can then select the visible collection
by selecting a tab or menu option.
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Adding/Removing/Moving Panes
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Registries

• Registries are used to define the portal
  components
• Portlets
• Controllers (Layouts)
• Controls (Decorators)
• Skins
• Media Types
• Registries can be defined in multiple files with
  the extension .xreg and placed in the webapps
  WEB-INF/conf directory. This allows for easily
  integrating new registries into the portal.

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Portlet Registry Entry Types
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Referencing Registry Entries in PSML
-- Referencing a portlet ltentry
parentStockQuote/gt -- Referencing a
controller ltcontroller name"TabController"/gt -
- Referencing a skin ltskin name"orange-red"/gt
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Complete Portal Page Layout

• Looking deeper into how Jetspeed works, we can
  see how the web application framework, Turbine,
  is used in the portal container implementation of
  Jetspeed. Turbine is a Model-View-Controller
  (MVC-2) type servlet framework. It introduces the
  concept of modules
• Layouts controls the layout of the entire web
  page.
• Navigations Top, Bottom, Right, Left areas of
  the web page
• Screens (templates) the center area of the web
  page, where the PSML is placed.

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• All of these modules are defined as templates.
  Jetspeed supports two templating engines
• Apache Velocity
• JSP (Java Server Pages)

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Velocity

• Velocity is a java-based template engine, a
  simple and powerful development tool that allows
  you to easily create and render documents that
  format and present your data.
• We make servlet development with velocity very
  easy if you use our provided class
  VelocityServlet as a base class for your servlet,
  and offer a utility class to help with
  application development.

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The Velocity Fundamental Pattern

• Initialize velocity. This applies to both usage
  patterns for velocity, the singleton as well as
  the 'separate runtime instance', and you only do
  this once.
• Create a context object (more on what that is
  later).
• Add your data objects to the context.
• Choose a template.
• 'Merge' the template and your data to produce the
  output.

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Editing Templates
When configuring a website, you will need to edit
the default layouts, navigations and screen
template modules. For the default site, all of
these templates are defined in Velocity. You can
find all templates under the /WEB-INF/templates
directory in the web application.
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Profile Requests

• When a request is received by the portal, the
  Profiler will map the request to template and
  PSML resources based on request parameters and
  user information. When no user information is
  available, the profiler will know to provide
  anonymous PSML content. The profile uses a
  fallback algorithm to find templates and PSML.
  This fallback algorithm first searches for the
  most specific resource, and then falls back to
  least specific resources. Here are the criteria
  listed from most to least specific
• Country Code
• Language
• Media Type
• User Type

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Media Types

• Media Types are defined in the Media Type
  registry. Currently Jetspeed has 3 entries in the
  registry
• HTML
• WML
• VXML

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Velocity and JSP
In order to incorporate dynamic content into your
web pages and portlets, it is strongly
recommended to use a templating engine such as
Velocity or JSP. Here we demonstrate Jetspeeds
Tools and how they can be used with the Velocity
Templating Engine. Velocity allows you to access
these tools by specifying a dollar sign to
denote the tool. Similarly, you can put easily
expose your business objects to the designer.
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Common Portlets
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Demo Portlets
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Admin Portlets
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Security Model

• Jetspeed provides secure access to the portal.
  The basic security model has
• Users users in the portal system.
• Permissions portal permissions to portal
  resources (view, customize, minimize, maximize)
• Groups Users can be associated to groups
  through roles.
• Roles Users can have several roles. Roles
  control access to portal resources (such as
  portlets, PSML).

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Example of a security role in a portlet
registry ltportlet-entry type"ref"
parent"CustomizerVelocity" name"UserForm" gt
ltsecurity role"admin"/gt .
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Databases
Jetspeed stores its security information in a
relational database. The PSML can also be
configured to be stored in a database. The
default system comes installed with a
HypersonicSQL database pre-populated with the
demo system data. Jetspeed can be easily
configured to work with most leading database
systems by changing the settings in the
TurbineResources.properties database.default.driv
erorg.hsql.jdbcDriver database.default.urljdbcH
ypersonicSQLwebappRoot/WEB-INF/db/jetspeed dat
abase.default.usernamesa database.default.passwor
d database.adaptorDBHypersonicSQL database.adapt
or.DBHypersonicSQLorg.hsql.jdbcDriver
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A Little Example
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HelloWorld Portlets

• 1?Implement and compile the portlet
• 2?Create the portlet registry fragment
• 3?Put the compiled portlet in the appropriate
  location
• 4?Register the portlet with the Jetspeed portlet
  registry

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Create a Simple Hello World portlet

• package com.bluesunrise.portal.portlets
• Import org.apache.jetspeed.portal.
• portlets.AbstractPortlet
• importorg.apache.turbine.util.RunData
• import org.apache.ecs.ConcreteElement
• import org.apache.ecs.StringElement
• public class HelloWorldPortlet extends
  AbstractPortlet
• public ConcreteElement getContent (RunData
  runData)
• return (new StringElement ("Hello
  Worldtest!"))

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Location

• Once the java code is compiled, the class has to
  be placed in the classpath. For this example the
  classpath is lttomcat_homegt/ltjetspeed_directorygt/we
  b-INF/classes/com/bluesunrise/
• Portal/portlets/.

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Hello World! Portlet registry fragment

• lt?xml version"1.0" encoding"UTF-8"?gt ltregistrygt
  
• ltportlet-entry name"HelloWorld" hidden"false"
  type"instance" application"false"gt
• ltmeta-infogt
• lttitlegtHelloWorldlt/titlegt ltdescriptiongtHello
  Worldlt/descriptiongt lt/meta-infogt
  ltclassnamegtcom.bluesunrise.portal.portlets.HelloWo
  rldPortletlt/classnamegt ltmedia-type ref"html"/gt
• lt/portlet-entrygt
• lt/registrygt

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• Jetspeed is easy to use, I think I will be
  accepted commonly.

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5?My Idea
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When Do portlets Make the Most Sense?

• If your goal is to bring together your web
  applications and information into one convenient
  place, portlets are the obvious choice. If your
  development goals are somewhat different,
  consider portlet and portal server features that
  you might want to take advantage of.

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Thank you !!!