Qs after reviewing Java dynamic metadata resolvers

[Rod Widdowson]

This is slightly off-topic and apologies if it has been answered and I missed it.

What is the proposed mechanism for expiring the cache entries and do you intend having a way of it happening automatically ('Oh that
cached info is out of date I'll delete the file') as part of the refresh at background/init time?  I can see two potential
mechanisms, the SAML based ones (validUntil and its partners in crime) and HTTP etags (in association, I guess, with queries) 

The former seems more logical and naturally extends to the "load all of this directory as metadata" thing that the TestShib
maintainers (amongst others) want.  It is slightly "off" in that it sort of break hierarchy in that you have to crack the SAML to
check validity, but I guess you have to do that anyway  because (I assume) you'll want to behave similarly if the signature is
invalid - why spend the rest of your life loading a file with an invalid signature?.

The latter then becomes needless, albeit a useful optimization.  I do have to say that I really love the way that the SP persists
the etag and would really like to see this come to Java.  ISTR that last time I looked I came to the conclusion that it just doesn't
fit into the batch providers in an easy way but the dynamic ones might?

Needless or not, having etags becomes a nice way of hurrying up revocation.  But at that stage I am straying to details of the MDQ
protocol: does it specify etags, or explicitly rule them out? I just don't have that swapped in right now so I cannot make a
meaningful contribution.  So I'll shut up.

/Rod