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   /*
    * 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 org.jboss.netty.bootstrap;
  
  import java.net.InetSocketAddress;
  import java.net.SocketAddress;
  
  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.ChannelPipeline;
  import org.jboss.netty.channel.ChannelPipelineException;
  import org.jboss.netty.channel.ChannelPipelineFactory;
  import org.jboss.netty.channel.Channels;
  
  /**
   * A helper class which creates a new server-side {@link Channel} for a
   * connectionless transport.
   *
   * <h3>Only for connectionless transports</h3>
   *
   * This bootstrap is for connectionless transports only such as UDP/IP.
   * Use {@link ServerBootstrap} instead for connection oriented transports.
   * Do not use this helper if you are using a connection oriented transport such
   * as TCP/IP and local transport which accepts an incoming connection and lets
   * the accepted child channels handle received messages.
   *
   * <h3>Configuring channels</h3>
   *
   * {@link #setOption(String, Object) Options} are used to configure a channel:
   *
   * <pre>
   * {@link ConnectionlessBootstrap} b = ...;
   *
   * // Options for a new channel
   * b.setOption("localAddress", new {@link InetSocketAddress}(8080));
   * b.setOption("tcpNoDelay", true);
   * b.setOption("receiveBufferSize", 1048576);
   * </pre>
   *
   * For the detailed list of available options, please refer to
   * {@link ChannelConfig} and its sub-types.
   *
   * <h3>Configuring a 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 ConnectionlessBootstrap} 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 ConnectionlessBootstrap} 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 ConnectionlessBootstrap} 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 ConnectionlessBootstrap}.  Therefore, it is OK to create as
  * many {@link ConnectionlessBootstrap} instances as you want with the same
  * {@link ChannelFactory} to apply different settings for different
  * {@link Channel}s.
  *
  * @apiviz.landmark
  */
 public class ConnectionlessBootstrap extends Bootstrap {
 
     /**
      * Creates a new instance with no {@link ChannelFactory} set.
      * {@link #setFactory(ChannelFactory)} must be called before any I/O
      * operation is requested.
      */
     public ConnectionlessBootstrap() {
     }
 
     /**
      * Creates a new instance with the specified initial {@link ChannelFactory}.
      */
     public ConnectionlessBootstrap(ChannelFactory channelFactory) {
         super(channelFactory);
     }
 
     /**
      * 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 ConnectionlessBootstrap} 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");
         }
 
         ChannelPipeline pipeline;
         try {
             pipeline = getPipelineFactory().getPipeline();
         } catch (Exception e) {
             throw new ChannelPipelineException("Failed to initialize a pipeline.", e);
         }
 
         Channel ch = getFactory().newChannel(pipeline);
 
         // Apply options.
         boolean success = false;
         try {
             ch.getConfig().setOptions(getOptions());
             success = true;
         } finally {
             if (!success) {
                 ch.close();
             }
         }
 
         // Bind
         ChannelFuture future = ch.bind(localAddress);
 
         // Wait for the future.
         future.awaitUninterruptibly();
         if (!future.isSuccess()) {
             future.getChannel().close().awaitUninterruptibly();
             throw new ChannelException("Failed to bind to: " + localAddress, future.getCause());
         }
 
         return ch;
     }
 
     /**
      * Creates a new connected channel with the current {@code "remoteAddress"}
      * and {@code "localAddress"} option.  If the {@code "localAddress"} option
      * is not set, the local address of a new channel is determined
      * automatically. This method is similar to the following code:
      *
      * <pre>
      * {@link ConnectionlessBootstrap} b = ...;
      * b.connect(b.getOption("remoteAddress"), b.getOption("localAddress"));
      * </pre>
      *
      * @return a future object which notifies when the creation of the connected
      *         channel succeeds or fails
      *
      * @throws IllegalStateException
      *         if {@code "remoteAddress"} option was not set
      * @throws ClassCastException
      *         if {@code "remoteAddress"} or {@code "localAddress"} option's
      *            value is neither a {@link SocketAddress} nor {@code null}
      * @throws ChannelPipelineException
      *         if this bootstrap's {@link #setPipelineFactory(ChannelPipelineFactory) pipelineFactory}
      *            failed to create a new {@link ChannelPipeline}
      */
     public ChannelFuture connect() {
         SocketAddress remoteAddress = (SocketAddress) getOption("remoteAddress");
         if (remoteAddress == null) {
             throw new IllegalStateException("remoteAddress option is not set.");
         }
         return connect(remoteAddress);
     }
 
     /**
      * Creates a new connected channel with the specified
      * {@code "remoteAddress"} and the current {@code "localAddress"} option.
      * If the {@code "localAddress"} option is not set, the local address of
      * a new channel is determined automatically.  This method is identical
      * with the following code:
      *
      * <pre>
      * {@link ConnectionlessBootstrap} b = ...;
      * b.connect(remoteAddress, b.getOption("localAddress"));
      * </pre>
      *
      * @return a future object which notifies when the creation of the connected
      *         channel succeeds or fails
      *
      * @throws ClassCastException
      *         if {@code "localAddress"} option's value is
      *            neither a {@link SocketAddress} nor {@code null}
      * @throws ChannelPipelineException
      *         if this bootstrap's {@link #setPipelineFactory(ChannelPipelineFactory) pipelineFactory}
      *            failed to create a new {@link ChannelPipeline}
      */
     public ChannelFuture connect(SocketAddress remoteAddress) {
         if (remoteAddress == null) {
             throw new NullPointerException("remotedAddress");
         }
         SocketAddress localAddress = (SocketAddress) getOption("localAddress");
         return connect(remoteAddress, localAddress);
     }
 
     /**
      * Creates a new connected channel with the specified
      * {@code "remoteAddress"} and the specified {@code "localAddress"}.
      * If the specified local address is {@code null}, the local address of a
      * new channel is determined automatically.
      *
      * @return a future object which notifies when the creation of the connected
      *         channel succeeds or fails
      *
      * @throws ChannelPipelineException
      *         if this bootstrap's {@link #setPipelineFactory(ChannelPipelineFactory) pipelineFactory}
      *            failed to create a new {@link ChannelPipeline}
      */
     public ChannelFuture connect(final SocketAddress remoteAddress, final SocketAddress localAddress) {
 
         if (remoteAddress == null) {
             throw new NullPointerException("remoteAddress");
         }
 
         ChannelPipeline pipeline;
         try {
             pipeline = getPipelineFactory().getPipeline();
         } catch (Exception e) {
             throw new ChannelPipelineException("Failed to initialize a pipeline.", e);
         }
 
         // Set the options.
         Channel ch = getFactory().newChannel(pipeline);
         boolean success = false;
         try {
             ch.getConfig().setOptions(getOptions());
             success = true;
         } finally {
             if (!success) {
                 ch.close();
             }
         }
 
         // Bind.
         if (localAddress != null) {
             ch.bind(localAddress);
         }
 
         // Connect.
         return ch.connect(remoteAddress);
     }
 }