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    1   /*
    2    * Copyright 2012 The Netty Project
    3    *
    4    * The Netty Project licenses this file to you under the Apache License,
    5    * version 2.0 (the "License"); you may not use this file except in compliance
    6    * with the 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.logging.Level;
    19  import java.util.logging.Logger;
    20
    21  import org.jboss.netty.buffer.ChannelBuffer;
    22  import org.jboss.netty.buffer.ChannelBuffers;
    23  import org.jboss.netty.channel.Channel;
    24  import org.jboss.netty.channel.ChannelEvent;
    25  import org.jboss.netty.channel.ChannelHandlerContext;
    26  import org.jboss.netty.channel.ChannelState;
    27  import org.jboss.netty.channel.ChannelStateEvent;
    28  import org.jboss.netty.channel.ExceptionEvent;
    29  import org.jboss.netty.channel.MessageEvent;
    30  import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
    31  import org.jboss.netty.channel.WriteCompletionEvent;
    32
    33  /**
    34   * Handles a client-side channel.
    35   */
    36  public class DiscardClientHandler extends SimpleChannelUpstreamHandler {
    37
    38      private static final Logger logger = Logger.getLogger(
    39              DiscardClientHandler.class.getName());
    40
    41      private long transferredBytes;
    42      private final byte[] content;
    43
    44      public DiscardClientHandler(int messageSize) {
    45          if (messageSize <= 0) {
    46              throw new IllegalArgumentException(
    47                      "messageSize: " + messageSize);
    48          }
    49          content = new byte[messageSize];
    50      }
    51
    52      public long getTransferredBytes() {
    53          return transferredBytes;
    54      }
    55
    56      @Override
    57      public void handleUpstream(ChannelHandlerContext ctx, ChannelEvent e) throws Exception {
    58          if (e instanceof ChannelStateEvent) {
    59              if (((ChannelStateEvent) e).getState() != ChannelState.INTEREST_OPS) {
    60                  logger.info(e.toString());
    61              }
    62          }
    63
    64          // Let SimpleChannelHandler call actual event handler methods below.
    65          super.handleUpstream(ctx, e);
    66      }
    67
    68      @Override
    69      public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) {
    70          // Send the initial messages.
    71          generateTraffic(e);
    72      }
    73
    74      @Override
    75      public void channelInterestChanged(ChannelHandlerContext ctx, ChannelStateEvent e) {
    76          // Keep sending messages whenever the current socket buffer has room.
    77          generateTraffic(e);
    78      }
    79
    80      @Override
    81      public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) {
    82          // Server is supposed to send nothing.  Therefore, do nothing.
    83      }
    84
    85      @Override
    86      public void writeComplete(ChannelHandlerContext ctx, WriteCompletionEvent e) {
    87          transferredBytes += e.getWrittenAmount();
    88      }
    89
    90      @Override
    91      public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) {
    92          // Close the connection when an exception is raised.
    93          logger.log(
    94                  Level.WARNING,
    95                  "Unexpected exception from downstream.",
    96                  e.getCause());
    97          e.getChannel().close();
    98      }
    99
    100     private void generateTraffic(ChannelStateEvent e) {
    101         // Keep generating traffic until the channel is unwritable.
    102         // A channel becomes unwritable when its internal buffer is full.
    103         // If you keep writing messages ignoring this property,
    104         // you will end up with an OutOfMemoryError.
    105         Channel channel = e.getChannel();
    106         while (channel.isWritable()) {
    107             ChannelBuffer m = nextMessage();
    108             if (m == null) {
    109                 break;
    110             }
    111             channel.write(m);
    112         }
    113     }
    114
    115     private ChannelBuffer nextMessage() {
    116         return ChannelBuffers.wrappedBuffer(content);
    117     }
    118 }