Public render parameters allows several portlets on the same page to share render parameters. Similarly to how portlet events are handled by Simple Portal, pages are natural scopes for shared render parameters. Simple Portal's tag library provides for the definition of initial values for such parameters allowing developpers to configure different pages initialized with different values of the same parameter. This is accomplished via the pageparam tag.

In the above example, we specify that the shared render parameter (or page parameter) identified by the attribute pair localName ( zipcode in the example) and namespaceURI ( urn:jboss:portal:simple:google in the example) will be initialized with the value 80201 the first time the page is rendered. This value can change if any portlet supporting this shared parameter updates it during an interaction triggered by the end user. However it is possible to make this parameter unmodifiable (i.e. the parameter value will not change even if a portlet tries to update it) by setting the optional frozen attribute to the true value.