Class OioServerSocketChannelFactory

java.lang.Object
org.jboss.netty.channel.socket.oio.OioServerSocketChannelFactory
All Implemented Interfaces:
ChannelFactory, ServerChannelFactory, ServerSocketChannelFactory, ExternalResourceReleasable
public class OioServerSocketChannelFactory extends Object implements ServerSocketChannelFactory
A ServerSocketChannelFactory which creates a server-side blocking I/O based ServerSocketChannel. It utilizes the good old blocking I/O API which is known to yield better throughput and latency when there are relatively small number of connections to serve.

How threads work

There are two types of threads in a OioServerSocketChannelFactory; one is boss thread and the other is worker thread.

Boss threads

Each bound ServerSocketChannel has its own boss thread. For example, if you opened two server ports such as 80 and 443, you will have two boss threads. A boss thread accepts incoming connections until the port is unbound. Once a connection is accepted successfully, the boss thread passes the accepted Channel to one of the worker threads that the OioServerSocketChannelFactory manages.

Worker threads

Each connected Channel has a dedicated worker thread, just like a traditional blocking I/O thread model.

Life cycle of threads and graceful shutdown

All threads are acquired from the Executors which were specified when a OioServerSocketChannelFactory was created. Boss threads are acquired from the bossExecutor, and worker threads are acquired from the workerExecutor. Therefore, you should make sure the specified Executors are able to lend the sufficient number of threads.

Both boss and worker threads are acquired lazily, and then released when there's nothing left to process. All the related resources are also released when the boss and worker threads are released. Therefore, to shut down a service gracefully, you should do the following:

  1. unbind all channels created by the factory,
  2. close all child channels accepted by the unbound channels, (these two steps so far is usually done using ChannelGroup.close())
  3. call releaseExternalResources().
Please make sure not to shut down the executor until all channels are closed. Otherwise, you will end up with a RejectedExecutionException and the related resources might not be released properly.

Limitation

A ServerSocketChannel created by this factory and its child channels do not support asynchronous operations. Any I/O requests such as "write" will be performed in a blocking manner.