Package com.linkedin.alpini.netty4.handlers

Class ChannelInitializer<C extends io.netty.channel.Channel>

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

com.linkedin.alpini.netty4.handlers.ChannelInitializer<C>

Type Parameters:

C - A sub-type of Channel

All Implemented Interfaces:

io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler

Direct Known Subclasses:

AsyncFullHttpRequestHandler, BasicServerChannelInitializer, SimpleChannelInitializer, SslInitializer

@Sharable
public abstract class ChannelInitializer<C extends io.netty.channel.Channel>
extends io.netty.channel.ChannelInboundHandlerAdapter

A special ChannelInboundHandler 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(io.netty.channel.ChannelHandler) , AbstractBootstrap.handler(io.netty.channel.ChannelHandler) and ServerBootstrap.childHandler(io.netty.channel.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 ChannelHandler.Sharable and so the implementation must be safe to be re-used.

Note that this contains a workaround for https://github.com/netty/netty/issues/8616

Nested Class Summary

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

io.netty.channel.ChannelHandler.Sharable

Constructor Summary

Constructors

Constructor	Description
ChannelInitializer()

Method Summary

Modifier and Type	Method	Description
final void	channelRegistered(io.netty.channel.ChannelHandlerContext ctx)
protected io.netty.channel.ChannelHandlerContext	currentContext()
void	exceptionCaught(io.netty.channel.ChannelHandlerContext ctx, Throwable cause)	Handle the Throwable by logging and closing the Channel.
void	handlerAdded(io.netty.channel.ChannelHandlerContext ctx)	If override this method ensure you call super!
void	handlerRemoved(io.netty.channel.ChannelHandlerContext ctx)	If override this method ensure you call super!
protected abstract void	initChannel(C ch)	This method will be called once the Channel was registered.

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelActive, channelInactive, channelRead, channelReadComplete, channelUnregistered, channelWritabilityChanged, userEventTriggered

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

ensureNotSharable, isSharable

Methods inherited from class java.lang.Object

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

Constructor Details

ChannelInitializer

public ChannelInitializer()

Method Details

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 exceptionCaught(ChannelHandlerContext, Throwable) which will by default close the Channel.

channelRegistered

public final void channelRegistered(io.netty.channel.ChannelHandlerContext ctx)
                             throws Exception

Specified by:

channelRegistered in interface io.netty.channel.ChannelInboundHandler

Overrides:

channelRegistered in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

Exception

exceptionCaught

public void exceptionCaught(io.netty.channel.ChannelHandlerContext ctx,
 Throwable cause)
                     throws Exception

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

Specified by:

exceptionCaught in interface io.netty.channel.ChannelHandler

Specified by:

exceptionCaught in interface io.netty.channel.ChannelInboundHandler

Overrides:

exceptionCaught in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

Exception

handlerAdded

public void handlerAdded(io.netty.channel.ChannelHandlerContext ctx)
                  throws Exception

If override this method ensure you call super!

Specified by:

handlerAdded in interface io.netty.channel.ChannelHandler

Overrides:

handlerAdded in class io.netty.channel.ChannelHandlerAdapter

Throws:

Exception

handlerRemoved

public void handlerRemoved(io.netty.channel.ChannelHandlerContext ctx)
                    throws Exception

If override this method ensure you call super!

Specified by:

handlerRemoved in interface io.netty.channel.ChannelHandler

Overrides:

handlerRemoved in class io.netty.channel.ChannelHandlerAdapter

Throws:

Exception

currentContext

protected io.netty.channel.ChannelHandlerContext currentContext()