[wsrp] RuntimeContext.namespacePrefix comment

[Rich Thompson <richt2@us.ibm.com>]

As I read through draft 09, it stuck
out to me again that we have two very similar fields next to each other
in the RuntimeContext structure (portletInstanceKey and namespacePrefix).
I wondered if we should do more to distinguish these from each other. My
understanding:

- portletInstanceKey: This is a key
the Consumer uses for the instance of the portlet. In general this will
be unique, with an exception for when to views onto the same portlet instance
(presumably with different navState) are included on a page. This key tends
to be scoped by the portletHandle and is required to be unique within the
RegistrationContext. Because of this uniqueness, multiple instances of
the portlet can use this key to uniquely namespace internal data when some
shared data space is in use.

- namespacePrefix: This string is unique
to the view of the Portlet, but its uniqueness is only scoped to the construction
of the current page. This is useful as a prefix in markup, even when multiple
instances or views on a portlet are included on the page. While it is likely
that Consumers use some key which has a longer lifetime, portlets can not
depend on it.

While these have a significant overlap,
do people think we have described the differences sufficiently in the spec?

Rich