Module io.netty5.transport

Package io.netty5.channel

Class ChannelInitializer<C extends Channel>

java.lang.Object

io.netty5.channel.ChannelInitializer<C>

Type Parameters:

C - A sub-type of Channel

All Implemented Interfaces:

ChannelHandler

public abstract class ChannelInitializer<C extends Channel>
extends Object
implements ChannelHandler

A special ChannelHandler which offers an easy way to initialize a Channel once it was registered to its EventLoop. Implementations are most often used in the context of AbstractBootstrap.handler(ChannelHandler) , AbstractBootstrap.handler(ChannelHandler) and ServerBootstrap.childHandler(ChannelHandler) to setup the ChannelPipeline of a Channel.

 public class MyChannelInitializer extends ChannelInitializer {
     public void initChannel(Channel channel) {
         channel.pipeline().addLast("myHandler", new MyHandler());
     }
 }

 ServerBootstrap bootstrap = ...;
 ...
 bootstrap.childHandler(new MyChannelInitializer());
 ...
 

Be aware that this class is marked as isSharable() and so the implementation must be safe to be re-used.

Constructor Summary

Constructors

Constructor	Description
ChannelInitializer()

Method Summary

Modifier and Type	Method	Description
void	channelExceptionCaught(ChannelHandlerContext ctx, Throwable cause)	Handle the Throwable by logging and closing the Channel.
void	handlerAdded(ChannelHandlerContext ctx)	Gets called after the ChannelHandler was added to the actual context and it's ready to handle events.
protected abstract void	initChannel(C ch)	This method will be called once the Channel was registered.
boolean	isSharable()	Returns true if this handler is sharable and thus can be added to more than one ChannelPipeline.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.netty5.channel.ChannelHandler

bind, channelActive, channelInactive, channelInboundEvent, channelRead, channelReadComplete, channelRegistered, channelShutdown, channelUnregistered, channelWritabilityChanged, close, connect, deregister, disconnect, flush, handlerRemoved, pendingOutboundBytes, read, register, sendOutboundEvent, shutdown, write

Constructor Detail

ChannelInitializer

public ChannelInitializer()

Method Detail

isSharable

public boolean isSharable()

Description copied from interface: ChannelHandler

Returns true if this handler is sharable and thus can be added to more than one ChannelPipeline. By default, this method returns false. If this method returns false, you have to create a new handler instance every time you add it to a pipeline because it has unshared state such as member variables.

Specified by:

isSharable in interface ChannelHandler

initChannel

protected abstract void initChannel(C ch)
                             throws Exception

This method will be called once the Channel was registered. After the method returns this instance will be removed from the ChannelPipeline of the Channel.

Parameters:

ch - the Channel which was registered.

Throws:

Exception - is thrown if an error occurs. In that case it will be handled by channelExceptionCaught(ChannelHandlerContext, Throwable) which will by default close the Channel.

channelExceptionCaught

public void channelExceptionCaught(ChannelHandlerContext ctx,
                                   Throwable cause)
                            throws Exception

Handle the Throwable by logging and closing the Channel. Sub-classes may override this.

Specified by:

channelExceptionCaught in interface ChannelHandler

Throws:

Exception

handlerAdded

public void handlerAdded(ChannelHandlerContext ctx)
                  throws Exception

Gets called after the ChannelHandler was added to the actual context and it's ready to handle events. If override this method ensure you call super!

Specified by:

handlerAdded in interface ChannelHandler

Throws:

Exception