StorageService API

[Marvin S. Addison]

>> I think I can explore it fairly natural in the context of a
>> TicketCache wrapper around StorageService. I think I can have something
>> ready for review by end of week.
>
> Cool, thx. No rush from my side, I'm buried with OSU work and getting into
> some SP bugs right now.

I had time today to knock this out:

https://github.com/serac/shibboleth-idp-ext-cas/commit/02928ffd3a60eaf616019d0119a7775fe01fab89

Most of the magic is in the net.shibboleth.idp.cas.ticket.metadata 
package, and DelegatingTicketStore demonstrates usage. This provides a 
fairly simple yet flexible persistence mechanism for simple types that 
have a natural key/value representation. Ticket obviously fell into that 
category. A point of potential improvement is to leverage 
StorageSerializer for a more general Object-String conversion mechanism 
for keys and values.

M