Portlet communication

IBM® WebSphere® Portal supports multiple ways for portlets to exchange or share information.

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Shared portlet state
These communication methods are based on shared state between multiple portlets. This means that two or more portlets read and write to the same data.
Publish/subscribe message based communication
These communication methods are based on directed communication links that pass information from a source portlet to a target portlet.
Special purpose techniques for data exchange
IBM WebSphere Portal supports special purpose techniques for data exchange.
Portlet events based communications
Portlet events provide a powerful and flexible publish/subscribe mechanism for communication between JSR 286 portlets. They can be used to exchange complex data between portlets and to trigger portlet activity such as updates to back end systems. In the portal, they can also interoperate with other communication mechanisms such as Cooperative portlets and click-to-action.
Cooperative portlets
Cooperative portlets represent an IBM specific API for publish/subscribe communication between portlets.
Interoperability between events and cooperative portlets
By concept, cooperative portlets are similar to JSR 286 portlet events. Both concepts describe publish/subscribe communication patterns that are based on typed information that is published and received by portlets and propagated via communication links.
Event broker
The portal event broker subsystem provides support for inter-portlet communication with active notifications using portlet events or the cooperative programming model.
Portlet wires
Portlet Wires are used to direct the information flow between portlets that communicate using JSR 286 Portlet events or the WebSphere Portal Cooperative portlets API.
Public render parameters
Public render parameters allow JSR 286 portlets to share navigational state information. They are specially useful for coordinating the multiple navigation or viewer portlets that display different information items that are all related to the same parameter name. The portal stores all portlet render parameters, including public render parameters, as an encoded part of the current portal URL. Therefore public render parameters are correctly preserved by typical browser navigation actions such as Back button and bookmarking.
Known issues and restrictions with portlet communication
Review this information for a list of known issues and restrictions with portlet communication.

Parent topic: Developing portlets

Related concepts:

Struts Portlet Framework