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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.channel.group;
    17
    18  import java.net.SocketAddress;
    19  import java.util.Set;
    20
    21  import org.jboss.netty.bootstrap.ServerBootstrap;
    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.ChannelHandlerContext;
    26  import org.jboss.netty.channel.ChannelStateEvent;
    27  import org.jboss.netty.channel.ServerChannel;
    28  import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
    29  import org.jboss.netty.util.CharsetUtil;
    30
    31  /**
    32   * A thread-safe {@link Set} that contains open {@link Channel}s and provides
    33   * various bulk operations on them.  Using {@link ChannelGroup}, you can
    34   * categorize {@link Channel}s into a meaningful group (e.g. on a per-service
    35   * or per-state basis.)  A closed {@link Channel} is automatically removed from
    36   * the collection, so that you don't need to worry about the life cycle of the
    37   * added {@link Channel}.  A {@link Channel} can belong to more than one
    38   * {@link ChannelGroup}.
    39   *
    40   * <h3>Broadcast a message to multiple {@link Channel}s</h3>
    41   * <p>
    42   * If you need to broadcast a message to more than one {@link Channel}, you can
    43   * add the {@link Channel}s associated with the recipients and call {@link ChannelGroup#write(Object)}:
    44   * <pre>
    45   * <strong>{@link ChannelGroup} recipients = new {@link DefaultChannelGroup}();</strong>
    46   * recipients.add(channelA);
    47   * recipients.add(channelB);
    48   * ..
    49   * <strong>recipients.write({@link ChannelBuffers}.copiedBuffer(
    50   *         "Service will shut down for maintenance in 5 minutes.",
    51   *         {@link CharsetUtil}.UTF_8));</strong>
    52   * </pre>
    53   *
    54   * <h3>Simplify shutdown process with {@link ChannelGroup}</h3>
    55   * <p>
    56   * If both {@link ServerChannel}s and non-{@link ServerChannel}s exist in the
    57   * same {@link ChannelGroup}, any requested I/O operations on the group are
    58   * performed for the {@link ServerChannel}s first and then for the others.
    59   * <p>
    60   * This rule is very useful when you shut down a server in one shot:
    61   *
    62   * <pre>
    63   * <strong>{@link ChannelGroup} allChannels = new {@link DefaultChannelGroup}();</strong>
    64   *
    65   * public static void main(String[] args) throws Exception {
    66   *     {@link ServerBootstrap} b = new {@link ServerBootstrap}(..);
    67   *     ...
    68   *
    69   *     // Start the server
    70   *     b.getPipeline().addLast("handler", new MyHandler());
    71   *     {@link Channel} serverChannel = b.bind(..);
    72   *     <strong>allChannels.add(serverChannel);</strong>
    73   *
    74   *     ... Wait until the shutdown signal reception ...
    75   *
    76   *     // Close the serverChannel and then all accepted connections.
    77   *     <strong>allChannels.close().awaitUninterruptibly();</strong>
    78   *     b.releaseExternalResources();
    79   * }
    80   *
    81   * public class MyHandler extends {@link SimpleChannelUpstreamHandler} {
    82   *     {@code @Override}
    83   *     public void channelOpen({@link ChannelHandlerContext} ctx, {@link ChannelStateEvent} e) {
    84   *         // Add all open channels to the global group so that they are
    85   *         // closed on shutdown.
    86   *         <strong>allChannels.add(e.getChannel());</strong>
    87   *     }
    88   * }
    89   * </pre>
    90   *
    91   * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
    92   * @author <a href="http://gleamynode.net/">Trustin Lee</a>
    93   * @version $Rev: 2122 $, $Date: 2010-02-02 11:00:04 +0900 (Tue, 02 Feb 2010) $
    94   *
    95   * @apiviz.landmark
    96   * @apiviz.has org.jboss.netty.channel.group.ChannelGroupFuture oneway - - returns
    97   */
    98  public interface ChannelGroup extends Set<Channel>, Comparable<ChannelGroup> {
    99
    100     /**
    101      * Returns the name of this group.  A group name is purely for helping
    102      * you to distinguish one group from others.
    103      */
    104     String getName();
    105
    106     /**
    107      * Returns the {@link Channel} whose ID matches the specified integer.
    108      *
    109      * @return the matching {@link Channel} if found. {@code null} otherwise.
    110      */
    111     Channel find(Integer id);
    112
    113     /**
    114      * Calls {@link Channel#setInterestOps(int)} for all {@link Channel}s in
    115      * this group with the specified {@code interestOps}. Please note that
    116      * this operation is asynchronous as {@link Channel#setInterestOps(int)} is.
    117      *
    118      * @return the {@link ChannelGroupFuture} instance that notifies when
    119      *         the operation is done for all channels
    120      */
    121     ChannelGroupFuture setInterestOps(int interestOps);
    122
    123     /**
    124      * Calls {@link Channel#setReadable(boolean)} for all {@link Channel}s in
    125      * this group with the specified boolean flag. Please note that this
    126      * operation is asynchronous as {@link Channel#setReadable(boolean)} is.
    127      *
    128      * @return the {@link ChannelGroupFuture} instance that notifies when
    129      *         the operation is done for all channels
    130      */
    131     ChannelGroupFuture setReadable(boolean readable);
    132
    133     /**
    134      * Writes the specified {@code message} to all {@link Channel}s in this
    135      * group. If the specified {@code message} is an instance of
    136      * {@link ChannelBuffer}, it is automatically
    137      * {@linkplain ChannelBuffer#duplicate() duplicated} to avoid a race
    138      * condition. Please note that this operation is asynchronous as
    139      * {@link Channel#write(Object)} is.
    140      *
    141      * @return the {@link ChannelGroupFuture} instance that notifies when
    142      *         the operation is done for all channels
    143      */
    144     ChannelGroupFuture write(Object message);
    145
    146     /**
    147      * Writes the specified {@code message} with the specified
    148      * {@code remoteAddress} to all {@link Channel}s in this group.  If the
    149      * specified {@code message} is an instance of {@link ChannelBuffer}, it is
    150      * automatically {@linkplain ChannelBuffer#duplicate() duplicated} to avoid
    151      * a race condition. Please note that this operation is asynchronous as
    152      * {@link Channel#write(Object, SocketAddress)} is.
    153      *
    154      * @return the {@link ChannelGroupFuture} instance that notifies when
    155      *         the operation is done for all channels
    156      */
    157     ChannelGroupFuture write(Object message, SocketAddress remoteAddress);
    158
    159     /**
    160      * Disconnects all {@link Channel}s in this group from their remote peers.
    161      *
    162      * @return the {@link ChannelGroupFuture} instance that notifies when
    163      *         the operation is done for all channels
    164      */
    165     ChannelGroupFuture disconnect();
    166
    167     /**
    168      * Unbinds all {@link Channel}s in this group from their local address.
    169      *
    170      * @return the {@link ChannelGroupFuture} instance that notifies when
    171      *         the operation is done for all channels
    172      */
    173     ChannelGroupFuture unbind();
    174
    175     /**
    176      * Closes all {@link Channel}s in this group.  If the {@link Channel} is
    177      * connected to a remote peer or bound to a local address, it is
    178      * automatically disconnected and unbound.
    179      *
    180      * @return the {@link ChannelGroupFuture} instance that notifies when
    181      *         the operation is done for all channels
    182      */
    183     ChannelGroupFuture close();
    184 }