This object is sent to registered MessageListeners by the portlet container when a portlet executes the send method of the PortletContext object. There are two important methods available in this object
getMessage: returns the message object sent with this event. Since this method returns a PortletMessage, the result must be cast to the appropriate type as illustrated in Example 7-1.
getRequest: returns the current PortletRequest. The request can be used to access the PortletSession object or to store data to be used in the doView method.