Public Comment

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Comment from: mo197@doc.ic.ac.uk

Name: Michelle Osmond
Organization: Imperial College London
Regarding Specification: WSRP v2

Hello,

I've had a look through the WSRP v2 draft 13 and have some comments and questions on inter-portlet communication and AJAX in portlets. 

I like the flexibility of being able to use both Event/Listener and shared state for communication between portlets. Could you clarify if:

 - event names and transient property names would not need to match across different portlets - Portals would allow users to set up connections between them at page construction time, somehow using the defined 'aliases'. Hopefully the user could connect events to listening portlets even without matching names/aliases.

 - "wsrp:consumerSession" scoped properties and events are shared among all portlets on the Consumer regardless of portlet app/Provider (i.e. default is cross-context communication)

 - navigation parameters are some kind of alternative to transient properties for sharing state, possibly something like Oracle's page parameters?


Also, is it correct that these features are not supported:

 - as a result of an Action, cause a page redirect *and* trigger an event (or transientProperty/navigationalParameter change). I would find this feature generally useful, e.g. select an item from a List portlet, send item ID in event, change page to go to the Item Display portlet. (In a BlockingInteractionResponse, you can have either an updateResponse or a redirectURL, not both.)

 - a Consumer Configured Portlet changing its own public event interface (publishedEvents and handledEvents), and its transientPropertyDescriptions, at runtime.

 - events triggering further events. Although the HandleEventsResponse Type does include an updateResponse, which might contain more events... is handleEvents called recursively?

 - automatically invalidate listening portlets' cache in handleEvents (6.2.1.2 says it's to be dealt with in a later spec). This might also need to be done on changing transient properties/navigation parameters.


I'd love to see support for using AJAX in portlets. (apologies for JSR168 terminology below, I don't know all the WSRP equivalents)

It looks like getResource could be useful - could a servlet resource retrieved this way read the portlet's own state, e.g. private session variables, portlet init params/preferences, current user details? This alone would be very useful, as I think the best we can do at the moment is to access Application-scope session variables and all other data needs to be passed in URL/cookies. 
Even better if the servlet could modify that portlet's session (portlet-scope).

I guess there still wouldn't be a way for an XMLHTTP request to trigger a Blocking Interaction and events/transient property/navigation param changes before the getMarkup.


Finally, two small things I noticed,
5.1.16, navigationParameterDescriptions has typo
  "to tha same Producer offered portlet handle"
6.1.2, portletInstanceKey sentence is slightly broken
  "to use this key when namespace multiple instances of itself within Producer supplied mechanisms"

Thanks,

-Michelle