Public Render Parameters retain value even when not in URL

[wjackter]

We are trying to use a public render parameter in one of our portlets but we are seeing some odd behavior with the value stored in the public parameter. If we have a public render parameter setup as appurl and append ?appurl=test into the URL, our portlet is properly displaying that appurl = test. However, if we then remove the parameter from the URL, the code is still displaying that appurl = test but it should display appurl = null. Why is the public render parameter retaining it's value even when no value is supplied in the URL?

We are using jboss portal 2.7.2 and 2.7.1 and the behavior was the same in both builds.

[wjackter]

Along with the above information, we have tried using bindings for both alias-binding and parameter-binding in the *-object.xml file and the outcome was always the same.

[apemberton]

Public Render URLs are a special type of Render URL as defined by the JSR286 (Portlet 2) specification. They are retained through multiple renders (and re-renders) of a given portlet and other portlets setup to use the shared parameter.

This is standard behavior for render parameters in the portal environment. See the JSR286 spec for more info: http://jcp.org/en/jsr/detail?id=286