1 /*
2 * Copyright 2019 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.internal;
17
18 import io.netty.util.concurrent.EventExecutor;
19 import io.netty.util.concurrent.FastThreadLocal;
20
21 import java.util.concurrent.Executor;
22 import java.util.concurrent.ThreadFactory;
23
24 /**
25 * Allow to retrieve the {@link EventExecutor} for the calling {@link Thread}.
26 */
27 public final class ThreadExecutorMap {
28
29 private static final FastThreadLocal<EventExecutor> mappings = new FastThreadLocal<EventExecutor>();
30
31 private ThreadExecutorMap() { }
32
33 /**
34 * Returns the current {@link EventExecutor} that uses the {@link Thread}, or {@code null} if none / unknown.
35 */
36 public static EventExecutor currentExecutor() {
37 return mappings.get();
38 }
39
40 /**
41 * Set the current {@link EventExecutor} that is used by the {@link Thread}.
42 */
43 private static void setCurrentEventExecutor(EventExecutor executor) {
44 mappings.set(executor);
45 }
46
47 /**
48 * Decorate the given {@link Executor} and ensure {@link #currentExecutor()} will return {@code eventExecutor}
49 * when called from within the {@link Runnable} during execution.
50 */
51 public static Executor apply(final Executor executor, final EventExecutor eventExecutor) {
52 ObjectUtil.checkNotNull(executor, "executor");
53 ObjectUtil.checkNotNull(eventExecutor, "eventExecutor");
54 return new Executor() {
55 @Override
56 public void execute(final Runnable command) {
57 executor.execute(apply(command, eventExecutor));
58 }
59 };
60 }
61
62 /**
63 * Decorate the given {@link Runnable} and ensure {@link #currentExecutor()} will return {@code eventExecutor}
64 * when called from within the {@link Runnable} during execution.
65 */
66 public static Runnable apply(final Runnable command, final EventExecutor eventExecutor) {
67 ObjectUtil.checkNotNull(command, "command");
68 ObjectUtil.checkNotNull(eventExecutor, "eventExecutor");
69 return new Runnable() {
70 @Override
71 public void run() {
72 setCurrentEventExecutor(eventExecutor);
73 try {
74 command.run();
75 } finally {
76 setCurrentEventExecutor(null);
77 }
78 }
79 };
80 }
81
82 /**
83 * Decorate the given {@link ThreadFactory} and ensure {@link #currentExecutor()} will return {@code eventExecutor}
84 * when called from within the {@link Runnable} during execution.
85 */
86 public static ThreadFactory apply(final ThreadFactory threadFactory, final EventExecutor eventExecutor) {
87 ObjectUtil.checkNotNull(threadFactory, "threadFactory");
88 ObjectUtil.checkNotNull(eventExecutor, "eventExecutor");
89 return new ThreadFactory() {
90 @Override
91 public Thread newThread(Runnable r) {
92 return threadFactory.newThread(apply(r, eventExecutor));
93 }
94 };
95 }
96 }