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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 io.netty.util.concurrent;
17  
18  import java.util.List;
19  import java.util.Set;
20  import java.util.concurrent.Callable;
21  import java.util.concurrent.ScheduledExecutorService;
22  import java.util.concurrent.TimeUnit;
23  
24  /**
25   * The {@link EventExecutorGroup} is responsible for providing the {@link EventExecutor}'s to use
26   * via its {@link #next()} method. Besides this, it is also responsible for handling their
27   * life-cycle and allows shutting them down in a global fashion.
28   *
29   */
30  public interface EventExecutorGroup extends ScheduledExecutorService, AutoCloseable {
31  
32      /**
33       * Returns {@code true} if and only if all {@link EventExecutor}s managed by this {@link EventExecutorGroup}
34       * are being {@linkplain #shutdownGracefully() shut down gracefuclly} or was {@linkplain #isShutdown() shut down}.
35       */
36      boolean isShuttingDown();
37  
38      /**
39       * Shortcut method for {@link #shutdownGracefully(long, long, TimeUnit)} with sensible default values.
40       *
41       * @return the {@link #terminationFuture()}
42       */
43      Future<?> shutdownGracefully();
44  
45      /**
46       * Signals this executor that the caller wants the executor to be shut down.  Once this method is called,
47       * {@link #isShuttingDown()} starts to return {@code true}, and the executor prepares to shut itself down.
48       * Unlike {@link #shutdown()}, graceful shutdown ensures that no tasks are submitted for <i>'the quiet period'</i>
49       * (usually a couple seconds) before it shuts itself down.  If a task is submitted during the quiet period,
50       * it is guaranteed to be accepted and the quiet period will start over.
51       *
52       * @param quietPeriod the quiet period as described in the documentation
53       * @param timeout     the maximum amount of time to wait until the executor is {@linkplain #shutdown()}
54       *                    regardless if a task was submitted during the quiet period
55       * @param unit        the unit of {@code quietPeriod} and {@code timeout}
56       *
57       * @return the {@link #terminationFuture()}
58       */
59      Future<?> shutdownGracefully(long quietPeriod, long timeout, TimeUnit unit);
60  
61      /**
62       * Returns the {@link Future} which is notified when all {@link EventExecutor}s managed by this
63       * {@link EventExecutorGroup} have been terminated.
64       */
65      Future<?> terminationFuture();
66  
67      /**
68       * @deprecated {@link #shutdownGracefully(long, long, TimeUnit)} or {@link #shutdownGracefully()} instead.
69       */
70      @Override
71      @Deprecated
72      void shutdown();
73  
74      /**
75       * @deprecated {@link #shutdownGracefully(long, long, TimeUnit)} or {@link #shutdownGracefully()} instead.
76       */
77      @Override
78      @Deprecated
79      List<Runnable> shutdownNow();
80  
81      /**
82       * Returns one of the {@link EventExecutor}s managed by this {@link EventExecutorGroup}.
83       */
84      EventExecutor next();
85  
86      /**
87       * Returns the unmodifiable set of {@link EventExecutor}s managed by this {@link EventExecutorGroup}.
88       */
89      <E extends EventExecutor> Set<E> children();
90  
91      @Override
92      Future<?> submit(Runnable task);
93  
94      @Override
95      <T> Future<T> submit(Runnable task, T result);
96  
97      @Override
98      <T> Future<T> submit(Callable<T> task);
99  
100     @Override
101     ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit);
102 
103     @Override
104     <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit);
105 
106     @Override
107     ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit);
108 
109     @Override
110     ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit);
111 }