The rich:hashParam component allows you to group client side parameters into a hash map in order to pass them to client API functions of any RichFaces components.

In this example we are packaging all the parameters for the show() method from a component control with nested a4j:param's instead of using static values. Since the show() method accepts event and an option hash as parameters all the values except the event is grouped using rich:hashParam and passed as as single hash value