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 * 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.netty.util.concurrent;
17
18 import java.util.Iterator;
19 import java.util.List;
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, Iterable<EventExecutor> {
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 gracefully} 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 @Override
87 Iterator<EventExecutor> iterator();
88
89 @Override
90 Future<?> submit(Runnable task);
91
92 @Override
93 <T> Future<T> submit(Runnable task, T result);
94
95 @Override
96 <T> Future<T> submit(Callable<T> task);
97
98 /**
99 * The ticker for this executor. Usually the {@link #schedule} methods will follow the
100 * {@link Ticker#systemTicker() system ticker} (i.e. {@link System#nanoTime()}), but especially for testing it is
101 * sometimes useful to have more control over the ticker. In that case, this method will be overridden. Code that
102 * schedules tasks on this executor should use this ticker in order to stay consistent with the executor (e.g. not
103 * be surprised by scheduled tasks running "early").
104 *
105 * @return The ticker for this scheduler
106 */
107 default Ticker ticker() {
108 return Ticker.systemTicker();
109 }
110
111 @Override
112 ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit);
113
114 @Override
115 <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit);
116
117 @Override
118 ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit);
119
120 @Override
121 ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit);
122 }