Inter portlet communication is a common
requirement for portlets. The portlets need a mechanism for this
communication. Prior to JSR 286, the portlets could either use the
APIs that were vendor specific or application scoped session objects
to achieve this. Eventing is an important JSR 286 feature that
enables portlets to communicate with each other. This article
explains the creation of a JSF 2.0 portlet application that uses the
JSR 286 eventing.The portlet application will be developed using
Portal toolkit which is available as a part of Rational Application
Developer v9.

The usecase will involve a portlet project containing two JSF portlets, the source portlet would publish the event and the target portlet would process that event. The portlets
would communicate with each other via JSR286 based events mechanism. Both the portlets would be deployed to the IBM WebShere Portal Server using Rational Application Developer(RAD). The article explains how easily such a sample can be created with minimal coding using RAD.

You can follow the detailed steps in article to create your own application and import the sample provided along with the package to your workspace for your reference.