io.netty.channel.ChannelInitializer Maven / Gradle / Ivy
/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.channel;
import io.netty.bootstrap.Bootstrap;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
/**
* A special {@link ChannelStateHandler} which offers an easy way to initialize a {@link Channel} once it was
* registered to its {@link EventLoop}.
*
* Implementations are most often used in the context of {@link Bootstrap#handler(ChannelHandler)} ,
* {@link ServerBootstrap#handler(ChannelHandler)} and {@link ServerBootstrap#childHandler(ChannelHandler)} to
* setup the {@link ChannelPipeline} of a {@link Channel}.
*
*
*
* public class MyChannelInitializer extends {@link ChannelInitializer} {
* public void initChannel({@link Channel} channel) {
* channel.pipeline().addLast("myHandler", new MyHandler());
* }
* }
*
* {@link ServerBootstrap} bootstrap = ...;
* ...
* bootstrap.childHandler(new MyChannelInitializer());
* ...
*
* Be aware that this class is marked as {@link Sharable} and so the implementation must be safe to be re-used.
*
* @param A sub-type of {@link Channel}
*/
@Sharable
public abstract class ChannelInitializer extends ChannelStateHandlerAdapter {
private static final InternalLogger logger = InternalLoggerFactory.getInstance(ChannelInitializer.class);
/**
* This method will be called once the {@link Channel} was registered. After the method returns this instance
* will be removed from the {@link ChannelPipeline} of the {@link Channel}.
*
* @param ch the {@link Channel} which was registered.
* @throws Exception is thrown if an error accours. In that case the {@link Channel} will be closed.
*/
protected abstract void initChannel(C ch) throws Exception;
@SuppressWarnings("unchecked")
@Override
public final void channelRegistered(ChannelHandlerContext ctx)
throws Exception {
boolean removed = false;
boolean success = false;
try {
initChannel((C) ctx.channel());
ctx.pipeline().remove(this);
removed = true;
ctx.fireChannelRegistered();
success = true;
} catch (Throwable t) {
logger.warn("Failed to initialize a channel. Closing: " + ctx.channel(), t);
} finally {
if (!removed) {
ctx.pipeline().remove(this);
}
if (!success) {
ctx.close();
}
}
}
@Override
public void inboundBufferUpdated(ChannelHandlerContext ctx) throws Exception {
ctx.fireInboundBufferUpdated();
}
}