Portlet Preference Persistence

[David Botterill <Da...@Sun.COM>]

I've read through the old mail archives and found a thread that said 
preferences were persisted in portletentityregistry.xml.  Is this really 
true?  When I store the preferences then check this file, I don't see 
the preferences.  I'd like to be able to verify that the preferences are 
actually being persisted when I "store" them.   Can anyone tell me how 
to do that?  Also, does Pluto read the persisted preferences when the 
portlet is loaded?

Thanks!
-David

Re: Portlet Preference Persistence

[David Botterill <Da...@Sun.COM>]

I found the answer.  Yes, portletentityregistry.xml will have the stored 
preferences.  There is one caveat.  In order for the store to work, you 
must get the preferences during an action request.  The spec says you 
have to store during an action request but not that you must GET the 
preferences during an action request.  In Pluto, the preferences are 
instantiated when you get them from the PortletRequest.  When the 
preferences are instantiated, the request type is passed in.   Here's 
the code from RenderRequestImpl.getPreferences().

        if (portletPreferences == null) {
            portletPreferences = PortletObjectAccess.getPortletPreferences(
                org.apache.pluto.Constants.METHOD_RENDER,
                super.getInternalPortletWindow().getPortletEntity()
            );
        }
PortletObjectAccess uses a factory to instantiate the preferences.  The 
bottom line is this, when you get the preferences, the request type 
(render or action) is always associated with that instance of the 
preferences.  The implication is that you can not get the preferences in 
a session context, keep them around, change them and then store them 
during an action request.  The workaround, of course, is to get the 
preferences from the action request just before you store.

This implementation seems cumbersome for frameworks such as JSF or 
Struts.  If you look at JSR-168 on this topic, however, you can see why 
the implementor(s) chose this design.  Here's the paragraph:

PLT 14.1 "Portlets have access to their preferences attributes through 
the PortletPreferences interface. Portlets have access to the associated 
PortletPreferences object while they are processing requests. Portlets 
may only modify preferences attributes during a processAction invocation."

For more information, please see my blog at http://blogs.sun.com/david.

Thanks!
-David

David Botterill wrote:

> I've read through the old mail archives and found a thread that said 
> preferences were persisted in portletentityregistry.xml.  Is this 
> really true?  When I store the preferences then check this file, I 
> don't see the preferences.  I'd like to be able to verify that the 
> preferences are actually being persisted when I "store" them.   Can 
> anyone tell me how to do that?  Also, does Pluto read the persisted 
> preferences when the portlet is loaded?
>
> Thanks!
> -David