[mina] New configuration API

[Trustin Lee]

Hi all,

This time, I refactored configuration API in 'sandbox/trustin/dirmina-158'.  Here's the link to the related JIRA issue:

http://issues.apache.org/jira/browse/DIRMINA-158

Here's the summary of what I've done in the branch:

* New interface: IoServiceConfig (includes filter chain builder configuration)
* New interface: IoAcceptorConfig extends IoServiceConfig (includes disconnectClientsOnUnbind property)
* New interface: IoConnectorConfig extends IoServiceConfig (includes connectTimeout property)
* New interface: IoSessionConfig (just an empty tag interface)

* All configuration getters and setters in transport-type specific acceptors, connectors, and sessions are moved to the implementations of the above interfaces.
** New method: IoService.getDefaultConfig(); // This is used when user didn't specify the configuration when you call bind() and connect().
** Changed method signature: IoAcceptor.bind( SocketAddress, IoHandler, IoServiceConfig );  // Instead of IoFilterChainBuilder
** Changed method signature: IoConnector.connect( SockeetAddress, IoHandler, IoServiceConfig );  // instead of IoFilterChainBuilder

Before the refactoring:

SocketAcceptor acceptor = new SocketAcceptor();
acceptor.setReuseAddress( true );
acceptor.bind( ... );
...
acceptor.setReuseAddress( false );
acceptor.bind( ... );

After the refactoring:

IoAcceptor acceptor = new SocketAcceptor();
SocketAcceptorConfig config1 = new SocketAcceptorConfig();
config1.setReuseAddress( true );
acceptor.bind( ..., config1 );

SocketAcceptorConfig config2 = new SocketAcceptorConfig();
config2.setReuseAddress( false );
acceptor.bind( ..., config2 );

The length of the code increased after the refactoring, but the former brings a mispreception that 'reuseAddress' property of all services bound to the acceptor is 'true'.

Because of all these configuration classes, there's no more session interface for specific transport type (e.g. SocketSession).  Instead, you have an IoSessionConfig implementation for the specific transport type. ( e.g. SocketSessionConfig). For example:

IoSession session = ...;
SocketSessionConfig cfg = ( SocketSessionConfig ) session.getConfig();
cfg.setReceiveBufferSize( 2048 );

The downside of this refactoring is that it makes us to downcast returned values too frequently when we change some settings.  I think this issue can be resolved by Covariant Return Type, which is introduced with Java 5.  We might have to consider to support Java 5 for simplicity.

As always, your feedback is welcome.

Trustin
--
what we call human nature is actually human habit
--
http://gleamynode.net/
PGP Key ID: 0x854B996C