org.jboss.netty.channel.socket.oio

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.

Constructor Summary

Constructors

Constructor and Description
OioServerSocketChannelFactory() Create a new OioServerSocketChannelFactory with a Executors.newCachedThreadPool() for the boss and worker executor.
OioServerSocketChannelFactory(Executor bossExecutor, Executor workerExecutor) Creates a new instance.

Method Summary

Methods

Modifier and Type	Method and Description
ServerSocketChannel	newChannel(ChannelPipeline pipeline) Creates and opens a new Channel and attaches the specified ChannelPipeline to the new Channel.
void	releaseExternalResources() Releases the external resources that this factory depends on to function.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

OioServerSocketChannelFactory

public OioServerSocketChannelFactory()

Create a new OioServerSocketChannelFactory with a Executors.newCachedThreadPool() for the boss and worker executor. See OioServerSocketChannelFactory(Executor, Executor)

OioServerSocketChannelFactory

public OioServerSocketChannelFactory(Executor bossExecutor,
                             Executor workerExecutor)

Creates a new instance.

Parameters:

bossExecutor - the Executor which will execute the boss threads

workerExecutor - the Executor which will execute the I/O worker threads

Method Detail

newChannel

public ServerSocketChannel newChannel(ChannelPipeline pipeline)

Description copied from interface: ChannelFactory

Creates and opens a new Channel and attaches the specified ChannelPipeline to the new Channel.

Specified by:

newChannel in interface ChannelFactory

Specified by:

newChannel in interface ServerChannelFactory

Specified by:

newChannel in interface ServerSocketChannelFactory

Parameters:

pipeline - the ChannelPipeline which is going to be attached to the new Channel

Returns:

the newly open channel

releaseExternalResources

public void releaseExternalResources()

Description copied from interface: ChannelFactory

Releases the external resources that this factory depends on to function. An external resource is a resource that this factory didn't create by itself. For example, Executors that you specified in the factory constructor are external resources. You can call this method to release all external resources conveniently when the resources are not used by this factory or any other part of your application. An unexpected behavior will be resulted in if the resources are released when there's an open channel which is managed by this factory.

Specified by:

releaseExternalResources in interface ChannelFactory

Specified by:

releaseExternalResources in interface ExternalResourceReleasable