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    1   /*
    2    * Copyright 2009 Red Hat, Inc.
    3    *
    4    * Red Hat licenses this file to you under the Apache License, version 2.0
    5    * (the "License"); you may not use this file except in compliance with the
    6    * License.  You may obtain a copy of the License at:
    7    *
    8    *    http://www.apache.org/licenses/LICENSE-2.0
    9    *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
    12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
    13   * License for the specific language governing permissions and limitations
    14   * under the License.
    15   */
    16  package org.jboss.netty.example.discard;
    17
    18  import java.util.concurrent.atomic.AtomicLong;
    19  import java.util.logging.Level;
    20  import java.util.logging.Logger;
    21
    22  import org.jboss.netty.buffer.ChannelBuffer;
    23  import org.jboss.netty.buffer.ChannelBuffers;
    24  import org.jboss.netty.channel.Channel;
    25  import org.jboss.netty.channel.ChannelEvent;
    26  import org.jboss.netty.channel.ChannelHandlerContext;
    27  import org.jboss.netty.channel.ChannelState;
    28  import org.jboss.netty.channel.ChannelStateEvent;
    29  import org.jboss.netty.channel.ExceptionEvent;
    30  import org.jboss.netty.channel.MessageEvent;
    31  import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
    32  import org.jboss.netty.channel.WriteCompletionEvent;
    33
    34  /**
    35   * Handles a client-side channel.
    36   *
    37   * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
    38   * @author <a href="http://gleamynode.net/">Trustin Lee</a>
    39   *
    40   * @version $Rev: 2121 $, $Date: 2010-02-02 09:38:07 +0900 (Tue, 02 Feb 2010) $
    41   */
    42  public class DiscardClientHandler extends SimpleChannelUpstreamHandler {
    43
    44      private static final Logger logger = Logger.getLogger(
    45              DiscardClientHandler.class.getName());
    46
    47      private final AtomicLong transferredBytes = new AtomicLong();
    48      private final byte[] content;
    49
    50      public DiscardClientHandler(int messageSize) {
    51          if (messageSize <= 0) {
    52              throw new IllegalArgumentException(
    53                      "messageSize: " + messageSize);
    54          }
    55          content = new byte[messageSize];
    56      }
    57
    58      public long getTransferredBytes() {
    59          return transferredBytes.get();
    60      }
    61
    62      @Override
    63      public void handleUpstream(ChannelHandlerContext ctx, ChannelEvent e) throws Exception {
    64          if (e instanceof ChannelStateEvent) {
    65              if (((ChannelStateEvent) e).getState() != ChannelState.INTEREST_OPS) {
    66                  logger.info(e.toString());
    67              }
    68          }
    69
    70          // Let SimpleChannelHandler call actual event handler methods below.
    71          super.handleUpstream(ctx, e);
    72      }
    73
    74      @Override
    75      public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) {
    76          // Send the initial messages.
    77          generateTraffic(e);
    78      }
    79
    80      @Override
    81      public void channelInterestChanged(ChannelHandlerContext ctx, ChannelStateEvent e) {
    82          // Keep sending messages whenever the current socket buffer has room.
    83          generateTraffic(e);
    84      }
    85
    86      @Override
    87      public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) {
    88          // Server is supposed to send nothing.  Therefore, do nothing.
    89      }
    90
    91      @Override
    92      public void writeComplete(ChannelHandlerContext ctx, WriteCompletionEvent e) {
    93          transferredBytes.addAndGet(e.getWrittenAmount());
    94      }
    95
    96      @Override
    97      public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) {
    98          // Close the connection when an exception is raised.
    99          logger.log(
    100                 Level.WARNING,
    101                 "Unexpected exception from downstream.",
    102                 e.getCause());
    103         e.getChannel().close();
    104     }
    105
    106     private void generateTraffic(ChannelStateEvent e) {
    107         // Keep generating traffic until the channel is unwritable.
    108         // A channel becomes unwritable when its internal buffer is full.
    109         // If you keep writing messages ignoring this property,
    110         // you will end up with an OutOfMemoryError.
    111         Channel channel = e.getChannel();
    112         while (channel.isWritable()) {
    113             ChannelBuffer m = nextMessage();
    114             if (m == null) {
    115                 break;
    116             }
    117             channel.write(m);
    118         }
    119     }
    120
    121     private ChannelBuffer nextMessage() {
    122         return ChannelBuffers.wrappedBuffer(content);
    123     }
    124 }