Hi all,
I just found a really interesting companion for mina applications, named
dnsjnio[1]. It is a set of utilities built around dnsjava and
distributed[2] under the MPL license to reuse 2 single threads for
resolving concurrently a queue of dns lookups.
Basically his exported interface is INonblockingResolver:
---
void sendAsync(Message message, Object id, ResolverListener
resolverListener);
Object sendAsync(final Message query, final ResponseQueue responseQueue);
void sendAsync(final Message query, Object id, final ResponseQueue
responseQueue);
void sendAsync(final Message query, Object id, int timeout, boolean
useTCP, final ResponseQueue responseQueue);
---
If I understood correcty the sourcecode the preferred way is the one
using the ResponseQueue.
You send any number of requests to sendAsync and then you can query the
ResponseQueue.isEmpty to know if any result has been received or simply
call ResponseQueue.remove to pop a result (this one blocks until one is
available).
Now I wonder what could be the best way to interact with such an
interface from a MINA based protocol: we have an SMTPClient that should
use it to resolve the MX servers and the A records before connecting and
an SMTPServer that runs a lot of DNS checks (anti-spam, e.g: SPF
lookups, resolvable sender, existing mx for sender domain, etc) for each
incoming connections.
Do you have any hint for me?
Is there anyone else already using this library? I guess that blocking
dns calls is probably a major pitfall for most mina based applications:
how did you solved the blocking issue in DNS if not using this library?
Thank you,
Stefano
[1]
http://blog.nominet.org.uk/tech/2006/08/08/nonblocking-extensions-to-dnsjava/
[2] http://download.nominet.org.uk/dnsjnio/
