/*
* Copyright 2011 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 org.jboss.netty.bootstrap;
import static org.jboss.netty.channel.Channels.*;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelConfig;
import org.jboss.netty.channel.ChannelException;
import org.jboss.netty.channel.ChannelFactory;
import org.jboss.netty.channel.ChannelFuture;
import org.jboss.netty.channel.ChannelHandler;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelPipelineFactory;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.Channels;
import org.jboss.netty.channel.ChildChannelStateEvent;
import org.jboss.netty.channel.ExceptionEvent;
import org.jboss.netty.channel.ServerChannelFactory;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
/**
* A helper class which creates a new server-side {@link Channel} and accepts
* incoming connections.
*
* <h3>Only for connection oriented transports</h3>
*
* This bootstrap is for connection oriented transports only such as TCP/IP
* and local transport. Use {@link ConnectionlessBootstrap} instead for
* connectionless transports. Do not use this helper if you are using a
* connectionless transport such as UDP/IP which does not accept an incoming
* connection but receives messages by itself without creating a child channel.
*
* <h3>Parent channel and its children</h3>
*
* A parent channel is a channel which is supposed to accept incoming
* connections. It is created by this bootstrap's {@link ChannelFactory} via
* {@link #bind()} and {@link #bind(SocketAddress)}.
* <p>
* Once successfully bound, the parent channel starts to accept incoming
* connections, and the accepted connections become the children of the
* parent channel.
*
* <h3>Configuring channels</h3>
*
* {@link #setOption(String, Object) Options} are used to configure both a
* parent channel and its child channels. To configure the child channels,
* prepend {@code "child."} prefix to the actual option names of a child
* channel:
*
* <pre>
* {@link ServerBootstrap} b = ...;
*
* // Options for a parent channel
* b.setOption("localAddress", new {@link InetSocketAddress}(8080));
* b.setOption("reuseAddress", true);
*
* // Options for its children
* b.setOption("child.tcpNoDelay", true);
* b.setOption("child.receiveBufferSize", 1048576);
* </pre>
*
* For the detailed list of available options, please refer to
* {@link ChannelConfig} and its sub-types.
*
* <h3>Configuring a parent channel pipeline</h3>
*
* It is rare to customize the pipeline of a parent channel because what it is
* supposed to do is very typical. However, you might want to add a handler
* to deal with some special needs such as degrading the process
* <a href="http://en.wikipedia.org/wiki/User_identifier_(Unix)">UID</a> from
* a <a href="http://en.wikipedia.org/wiki/Superuser">superuser</a> to a
* normal user and changing the current VM security manager for better
* security. To support such a case,
* the {@link #setParentHandler(ChannelHandler) parentHandler} property is
* provided.
*
* <h3>Configuring a child channel pipeline</h3>
*
* Every channel has its own {@link ChannelPipeline} and you can configure it
* in two ways.
*
* The recommended approach is to specify a {@link ChannelPipelineFactory} by
* calling {@link #setPipelineFactory(ChannelPipelineFactory)}.
*
* <pre>
* {@link ServerBootstrap} b = ...;
* b.setPipelineFactory(new MyPipelineFactory());
*
* public class MyPipelineFactory implements {@link ChannelPipelineFactory} {
* public {@link ChannelPipeline} getPipeline() throws Exception {
* // Create and configure a new pipeline for a new channel.
* {@link ChannelPipeline} p = {@link Channels}.pipeline();
* p.addLast("encoder", new EncodingHandler());
* p.addLast("decoder", new DecodingHandler());
* p.addLast("logic", new LogicHandler());
* return p;
* }
* }
* </pre>
* <p>
* The alternative approach, which works only in a certain situation, is to use
* the default pipeline and let the bootstrap to shallow-copy the default
* pipeline for each new channel:
*
* <pre>
* {@link ServerBootstrap} b = ...;
* {@link ChannelPipeline} p = b.getPipeline();
*
* // Add handlers to the default pipeline.
* p.addLast("encoder", new EncodingHandler());
* p.addLast("decoder", new DecodingHandler());
* p.addLast("logic", new LogicHandler());
* </pre>
*
* Please note 'shallow-copy' here means that the added {@link ChannelHandler}s
* are not cloned but only their references are added to the new pipeline.
* Therefore, you cannot use this approach if you are going to open more than
* one {@link Channel}s or run a server that accepts incoming connections to
* create its child channels.
*
* <h3>Applying different settings for different {@link Channel}s</h3>
*
* {@link ServerBootstrap} is just a helper class. It neither allocates nor
* manages any resources. What manages the resources is the
* {@link ChannelFactory} implementation you specified in the constructor of
* {@link ServerBootstrap}. Therefore, it is OK to create as many
* {@link ServerBootstrap} instances as you want with the same
* {@link ChannelFactory} to apply different settings for different
* {@link Channel}s.
*
* @apiviz.landmark
*/
public class ServerBootstrap extends Bootstrap {
private volatile ChannelHandler parentHandler;
/**
* Creates a new instance with no {@link ChannelFactory} set.
* {@link #setFactory(ChannelFactory)} must be called before any I/O
* operation is requested.
*/
public ServerBootstrap() {
super();
}
/**
* Creates a new instance with the specified initial {@link ChannelFactory}.
*/
public ServerBootstrap(ChannelFactory channelFactory) {
super(channelFactory);
}
/**
* {@inheritDoc}
*
* @throws IllegalArgumentException
* if the specified {@code factory} is not a
* {@link ServerChannelFactory}
*/
@Override
public void setFactory(ChannelFactory factory) {
if (factory == null) {
throw new NullPointerException("factory");
}
if (!(factory instanceof ServerChannelFactory)) {
throw new IllegalArgumentException(
"factory must be a " +
ServerChannelFactory.class.getSimpleName() + ": " +
factory.getClass());
}
super.setFactory(factory);
}
/**
* Returns an optional {@link ChannelHandler} which intercepts an event
* of a newly bound server-side channel which accepts incoming connections.
*
* @return the parent channel handler.
* {@code null} if no parent channel handler is set.
*/
public ChannelHandler getParentHandler() {
return parentHandler;
}
/**
* Sets an optional {@link ChannelHandler} which intercepts an event of
* a newly bound server-side channel which accepts incoming connections.
*
* @param parentHandler
* the parent channel handler.
* {@code null} to unset the current parent channel handler.
*/
public void setParentHandler(ChannelHandler parentHandler) {
this.parentHandler = parentHandler;
}
/**
* Creates a new channel which is bound to the local address which was
* specified in the current {@code "localAddress"} option. This method is
* similar to the following code:
*
* <pre>
* {@link ServerBootstrap} b = ...;
* b.bind(b.getOption("localAddress"));
* </pre>
*
* @return a new bound channel which accepts incoming connections
*
* @throws IllegalStateException
* if {@code "localAddress"} option was not set
* @throws ClassCastException
* if {@code "localAddress"} option's value is
* neither a {@link SocketAddress} nor {@code null}
* @throws ChannelException
* if failed to create a new channel and
* bind it to the local address
*/
public Channel bind() {
SocketAddress localAddress = (SocketAddress) getOption("localAddress");
if (localAddress == null) {
throw new IllegalStateException("localAddress option is not set.");
}
return bind(localAddress);
}
/**
* Creates a new channel which is bound to the specified local address.
*
* @return a new bound channel which accepts incoming connections
*
* @throws ChannelException
* if failed to create a new channel and
* bind it to the local address
*/
public Channel bind(final SocketAddress localAddress) {
if (localAddress == null) {
throw new NullPointerException("localAddress");
}
final BlockingQueue<ChannelFuture> futureQueue =
new LinkedBlockingQueue<ChannelFuture>();
ChannelHandler binder = new Binder(localAddress, futureQueue);
ChannelHandler parentHandler = getParentHandler();
ChannelPipeline bossPipeline = pipeline();
bossPipeline.addLast("binder", binder);
if (parentHandler != null) {
bossPipeline.addLast("userHandler", parentHandler);
}
Channel channel = getFactory().newChannel(bossPipeline);
// Wait until the future is available.
ChannelFuture future = null;
boolean interrupted = false;
do {
try {
future = futureQueue.poll(Integer.MAX_VALUE, TimeUnit.SECONDS);
} catch (InterruptedException e) {
interrupted = true;
}
} while (future == null);
if (interrupted) {
Thread.currentThread().interrupt();
}
// Wait for the future.
future.awaitUninterruptibly();
if (!future.isSuccess()) {
future.getChannel().close().awaitUninterruptibly();
throw new ChannelException("Failed to bind to: " + localAddress, future.getCause());
}
return channel;
}
private final class Binder extends SimpleChannelUpstreamHandler {
private final SocketAddress localAddress;
private final BlockingQueue<ChannelFuture> futureQueue;
private final Map<String, Object> childOptions =
new HashMap<String, Object>();
Binder(SocketAddress localAddress, BlockingQueue<ChannelFuture> futureQueue) {
this.localAddress = localAddress;
this.futureQueue = futureQueue;
}
@Override
public void channelOpen(
ChannelHandlerContext ctx,
ChannelStateEvent evt) {
try {
evt.getChannel().getConfig().setPipelineFactory(getPipelineFactory());
// Split options into two categories: parent and child.
Map<String, Object> allOptions = getOptions();
Map<String, Object> parentOptions = new HashMap<String, Object>();
for (Entry<String, Object> e: allOptions.entrySet()) {
if (e.getKey().startsWith("child.")) {
childOptions.put(
e.getKey().substring(6),
e.getValue());
} else if (!e.getKey().equals("pipelineFactory")) {
parentOptions.put(e.getKey(), e.getValue());
}
}
// Apply parent options.
evt.getChannel().getConfig().setOptions(parentOptions);
} finally {
ctx.sendUpstream(evt);
}
boolean finished = futureQueue.offer(evt.getChannel().bind(localAddress));
assert finished;
}
@Override
public void childChannelOpen(
ChannelHandlerContext ctx,
ChildChannelStateEvent e) throws Exception {
// Apply child options.
try {
e.getChildChannel().getConfig().setOptions(childOptions);
} catch (Throwable t) {
Channels.fireExceptionCaught(e.getChildChannel(), t);
}
ctx.sendUpstream(e);
}
@Override
public void exceptionCaught(
ChannelHandlerContext ctx, ExceptionEvent e)
throws Exception {
boolean finished = futureQueue.offer(failedFuture(e.getChannel(), e.getCause()));
assert finished;
ctx.sendUpstream(e);
}
}
}