Although a standard on InterPortlet Communication (IPC) is set to be addressed in the next version of the Portlet Specification (JSR-286), as we stand today there is no standardized way of addressing this shortfall in the first version of the Portlet Specification (JSR-168).
Those enterprise portal vendors who have chosen to address IPC, have had to create their own APIs, and JBoss Portal is no exception. With JBoss Portal 2.2, we listened to our community and customers and have included an IPC API that is easy to understand and implement.
The JBoss Portal IPC API, found in 2.2+, makes use of our PortalNode hierarchy. Essentially, all objects and components within the portal are considered branches on a tree.
A developer is now able to leverage this architecture philosophy within his own code to make portlet-linking and page-linking a reality. To enable the use of IPC, we have also added a chapter to the online Reference Documentation, and a sample download (source included) on PortletSwap. Hopefully, both items will help you get up to speed with this enterprise-level feature in JBoss Portal 2.2. The sample portlets will introduce developers to both the Page-linking and IPC mechanisms:
I invite you all to download the sample, flip through the docs, and let us know what you think in our forums.