Special purpose techniques for data exchange

IBM WebSphere Portal supports special purpose techniques for data exchange.

Cross-portlet links

This works for IBM and JSR portlets. With the advanced URL generation APIs for portlets, we can have a portlet create a line that points to another portlet, possibly even on a different page, and pass data to that portlet. If at all possible, use the publish/subscribe methods. Use explicit cross-portlet links only where other techniques are not applicable.

For example, this can be for communication between IBM and JSR portlets.

For details, refer to the documentation about the portalRenderURL tag and the PortalURLGenerationService. Such links can also be created from a theme JSP that use the portal URL generation tag.

For advanced use cases that require more control over the generated URLs, we can also use the portal state API.

Cookies

The Java Portlet Specification 2.0 adds support for portlets to read and set HTTP cookies. We can share cookies between portlets and other Web applications to track information about the current browser interaction without requiring a server side session and without consuming server resources.

Custom JavaScript data exchange

As portlets are Web components inside an HTML page, we can use any client side techniques to read, write or exchange data within the markup that your portlet provides. This includes sharing data via the page document object model (DOM) or use of client side JavaScript code or libraries.

Parent: Portlet communication
Related:
Shared portlet state
Publish/subscribe message based communication
Portlet events based communications
Cooperative portlets
Interoperability between events and cooperative portlets
Event broker
Portlet wires
Public render parameters
Known issues and restrictions with portlet communication
Related:

http://www-128.ibm.com/developerworks/websphere/library/techarticles/0612_behl/0612_behl.html

http://www-128.ibm.com/developerworks/websphere/library/techarticles/0603_behl/0603_behl.html