TLS ALPN Proposal v2

[Bradford Wetmore]

Hi,

I have just posted the second iteration of the ALPN proposal which 
hopefully addresses all of the comments raised here.  It is in javadoc 
format, but things can certainly be adjusted:

     http://cr.openjdk.java.net/~wetmore/8051498/webrev.00/

Please see the archive [1] for previous design discussion.  I will be 
writing up usage examples in the next few days.

The significant changes:

ExtendedSSLSession
     public List<String> getReceivedApplicationProtocols() {

     This will allow applications to examine which protocol names were
     sent.

SSLParameters
     mentions both ALPN/NPN as possible protocols.  I removed the
     discussion about "server" and "client" since ALPN/NPN essentially
     reverse the roles.

     mentions "appropriate character sets" for String-byte[] conversions
     such as UTF-8 for ALPN.

     The application protocol selector is now a @FunctionalInterface
     (i.e. lambda-ready) called SSLFunction.  It is to throw an
     SSLException if no values are supported, or null if you want to
     treat as an unknown extension.

     Defined constants for HTTP/1.1 and HTTP/2.

SSLSession

     Called out that getHandshakeSession's ciphersuite may vary until
     selected.

SSLBase

     A new marker interface that SSLEngine/SSLSocket will implement.
     This will allow for a single SSLFunction instead of having
     SSLFunctionSSLEngine and SSLFunctionSSLSocket.  It does require
     that the lambda do a instanceof, unless we were to move the common
     Socket/Engine APIs into this class.

Thanks,

Brad

[1] http://mail.openjdk.java.net/pipermail/security-dev/2015-May/012183.html