A Connection that acts as an interceptor between an EndPoint providing SSL encrypted data and another consumer of an EndPoint (typically an Connection like HttpConnection) that wants unencrypted data.

The connector uses an EndPoint (typically SocketChannelEndPoint) as it's source/sink of encrypted data. It then provides an endpoint via getSslEndPoint() to expose a source/sink of unencrypted data to another connection (eg HttpConnection).

The design of this class is based on a clear separation between the passive methods, which do not block nor schedule any asynchronous callbacks, and active methods that do schedule asynchronous callbacks.

The passive methods are SslEndPoint#fill(ByteBuffer) and SslEndPoint#flush(ByteBuffer...). They make best effort attempts to progress the connection using only calls to the encrypted EndPoint#fill(ByteBuffer) and EndPoint#flush(ByteBuffer...) methods. They will never block nor schedule any readInterest or write callbacks. If a fill/flush cannot progress either because of network congestion or waiting for an SSL handshake message, then the fill/flush will simply return with zero bytes filled/flushed. Specifically, if a flush cannot proceed because it needs to receive a handshake message, then the flush will attempt to fill bytes from the encrypted endpoint, but if insufficient bytes are read it will NOT call EndPoint#fillInterested(Callback).

It is only the active methods : SslEndPoint#fillInterested(Callback) and SslEndPoint#write(Callback, ByteBuffer...) that may schedule callbacks by calling the encrypted EndPoint#fillInterested(Callback) and EndPoint#write(Callback, ByteBuffer...) methods. For normal data handling, the decrypted fillInterest method will result in an encrypted fillInterest and a decrypted write will result in an encrypted write. However, due to SSL handshaking requirements, it is also possible for a decrypted fill to call the encrypted write and for the decrypted flush to call the encrypted fillInterested methods.

MOST IMPORTANTLY, the encrypted callbacks from the active methods (#onFillable() and WriteFlusher#completeWrite()) do no filling or flushing themselves. Instead they simple make the callbacks to the decrypted callbacks, so that the passive encrypted fill/flush will be called again and make another best effort attempt to progress the connection.