Portal Server & Portlet

What is portal server?

Aggregates the content for a page from different modules & renders
Provides options to personalize the content viewed on a page
User can also change the layout, look & feel that suits him the best


When is it good to go for portal servers?

When you have several modules on your web page
Each module can be deployed as a portlet & provide option for the user to pick & choose the required portlets

Available open source portal servers

Pluto
http://portals.apache.org/pluto - Pluto is the Reference Implementation of the Java Portlet Specification. The current version of this Portlet specification is JSR 168 1.0 Portlets are designed to run in the context of a portal. They are written to the Portlet API. Pluto implements the contract, the Portlet API, between portlets and portals. Pluto is a portlet container

Jboss Portal Server
http://www.jboss.com/products/jbossportal - JBoss Portal provides an open source platform for hosting and serving a portal's Web interface, publishing and managing its content, and customizing its experience. While most packaged Portal frameworks help enterprises launch Portals more quickly, only JBoss Portal delivers the benefits of a zero-cost open source license combined with a flexible and scalable underlying platform.

JetSpeed-2
http://portals.apache.org/jetspeed-2 - Jetspeed-2 is the next-generation enterprise portal at Apache. Jetspeed-2 offers several architectural enhancements and improvements over Jetspeed 1.0. First, Jetspeed-2 is conformant to the Java Portlet Standard and will provide a standard mechanism for the deployment of portlets. Second, Jetspeed-2 has matured to a more scalable architecture featuring multi-threaded functionality. Third, Jetspeed-2 is decoupled from several legacy open source projects. Fourth, Jetspeed-2 is based on component architecture.

eXo
http://www.exoplatform.com/portal/faces/public/exo - The eXo platform is a powerful Open Source - JSR 168 compliant - enterprise portal built from several modules.
Exo is based on innovative tools, APIs and frameworks such as JavaServer Faces, Pico Container, JbossMX and AspectJ

Liferay
http://www.liferay.com/ - Liferay is a leading provider of open source enterprise software, Liferay Portal Server supports many different application servers and servlet containers. Liferay Portal Enterprise requires a fully compliant J2EE application server whereas Liferay Portal Professional can run in a simple servlet container. Liferay portal server supports Resin Application Server.