TCP_NIO with SSL

From Hal Hildebrand:
Attached are the sources to allow a new protocol stack which uses SSL over
NIO. This protocol stack element provides security and authentication
(using client side authentication) for a JGroups TCP stack using NIO.

This required two minor modifications in the ConnectionTableNIO class.
These modifications allow one to subclass to create a connection table which
uses SSL for the connections. Finally, there is a new protocol stack
element, SSL_NIO, which one can add to a stack to make use of it.

Regardless of whether this makes it into the codeline of JGroups, it would
be nice to have the changes to ConnectionTableNIO make it into the mainline,
as I currently have to overwrite the original class to easily implement this

• the last thing I want to do is fork ConnectionTableNIO I'd rather just
  subclass it. The mods are simple and innocuous (marked with "HSH").

Right now, the SSL_NIO needs to be configured with an SSLSocketFactory. I
didn't bother with integrating with the normal JGroups mechanism using
properties from the configuration because I consider it inherently insecure
to ensconce my passwords in configuration files. But the changes to enable
this are straight forward. Currently, to configure the factory for the
protocol layer, do something like the following before connecting your
channel:

// Construct your Jchannel
JChannel jchannel = ...

// Access your protocol stack
ProtocolStack protocolStack = jchannel.getProtocolStack();

// Retrieve the SSL_NIO protocol layer
SSL_NIO protocol = (SSL_NIO) protocolStack.findProtocol("SSL_NIO");

// Create your SSLSocketFactory
SSLSocketFactory socketFactory = ....

// Set up the protocol
protocol. SetSocketFactory(socketFactory);

// Connect your channel
jchannel.connnect("my-group");

Cheers.