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1   /*
2    * Copyright 2021 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    *   https://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 io.netty5.channel;
17  
18  import io.netty5.util.concurrent.Future;
19  import io.netty5.util.concurrent.FutureContextListener;
20  
21  /**
22   * {@link FutureContextListener} listeners that take a context, and listens to the result of a {@link Future}.
23   * The result of the asynchronous {@link ChannelOutboundInvoker} I/O operation is notified once this listener is added
24   * by calling {@link Future#addListener(Object, FutureContextListener)} with the {@link ChannelOutboundInvoker} /
25   * {@link Channel} as context.
26   */
27  public final class ChannelFutureListeners {
28  
29      /**
30       * A {@link FutureContextListener} that closes the {@link ChannelOutboundInvoker} which is associated with
31       * the specified {@link Future}.
32       */
33      public static final FutureContextListener<ChannelOutboundInvoker, Object> CLOSE = new Close();
34  
35      /**
36       * A {@link FutureContextListener} that closes the {@link ChannelOutboundInvoker} when the operation ended up with
37       * a failure or cancellation rather than a success.
38       */
39      public static final FutureContextListener<ChannelOutboundInvoker, Object> CLOSE_ON_FAILURE = new CloseOnFailure();
40  
41      /**
42       * A {@link FutureContextListener} that forwards the {@link Throwable} of the {@link Future} into the
43       * {@link ChannelPipeline}. This mimics the old behavior of Netty 3.
44       */
45      public static final FutureContextListener<Channel, Object> FIRE_EXCEPTION_ON_FAILURE = new FireExceptionOnFailure();
46  
47      private ChannelFutureListeners() {
48      }
49  
50      private static final class Close implements FutureContextListener<ChannelOutboundInvoker, Object> {
51          @Override
52          public void operationComplete(ChannelOutboundInvoker context, Future<?> future) throws Exception {
53              context.close();
54          }
55      }
56  
57      private static final class CloseOnFailure implements FutureContextListener<ChannelOutboundInvoker, Object> {
58          @Override
59          public void operationComplete(ChannelOutboundInvoker context, Future<?> future) throws Exception {
60              if (future.isFailed()) {
61                  context.close();
62              }
63          }
64      }
65  
66      private static final class FireExceptionOnFailure implements FutureContextListener<Channel, Object> {
67          @Override
68          public void operationComplete(Channel context, Future<?> future) throws Exception {
69              if (future.isFailed()) {
70                  context.pipeline().fireChannelExceptionCaught(future.cause());
71              }
72          }
73      }
74  }