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 org.jboss.netty.util;
17
18 import org.jboss.netty.logging.InternalLogger;
19 import org.jboss.netty.logging.InternalLoggerFactory;
20
21
22 /**
23 * A {@link Runnable} that changes the current thread name and reverts it back
24 * when its execution ends. To change the default thread names set by Netty,
25 * use {@link #setThreadNameDeterminer(ThreadNameDeterminer)}.
26 *
27 * @apiviz.landmark
28 * @apiviz.has org.jboss.netty.util.ThreadNameDeterminer oneway - -
29 */
30 public class ThreadRenamingRunnable implements Runnable {
31
32 private static final InternalLogger logger =
33 InternalLoggerFactory.getInstance(ThreadRenamingRunnable.class);
34
35 private static volatile ThreadNameDeterminer threadNameDeterminer =
36 ThreadNameDeterminer.PROPOSED;
37
38 /**
39 * Returns the {@link ThreadNameDeterminer} which overrides the proposed
40 * new thread name.
41 */
42 public static ThreadNameDeterminer getThreadNameDeterminer() {
43 return threadNameDeterminer;
44 }
45
46 /**
47 * Sets the {@link ThreadNameDeterminer} which overrides the proposed new
48 * thread name. Please note that the specified {@link ThreadNameDeterminer}
49 * affects only new {@link ThreadRenamingRunnable}s; the existing instances
50 * are not affected at all. Therefore, you should make sure to call this
51 * method at the earliest possible point (i.e. before any Netty worker
52 * thread starts) for consistent thread naming. Otherwise, you might see
53 * the default thread names and the new names appear at the same time in
54 * the full thread dump.
55 */
56 public static void setThreadNameDeterminer(ThreadNameDeterminer threadNameDeterminer) {
57 if (threadNameDeterminer == null) {
58 throw new NullPointerException("threadNameDeterminer");
59 }
60 ThreadRenamingRunnable.threadNameDeterminer = threadNameDeterminer;
61 }
62
63 private final Runnable runnable;
64 private final String proposedThreadName;
65
66 /**
67 * Creates a new instance which wraps the specified {@code runnable}
68 * and changes the thread name to the specified thread name when the
69 * specified {@code runnable} is running.
70 */
71 public ThreadRenamingRunnable(Runnable runnable, String proposedThreadName) {
72 if (runnable == null) {
73 throw new NullPointerException("runnable");
74 }
75 if (proposedThreadName == null) {
76 throw new NullPointerException("proposedThreadName");
77 }
78 this.runnable = runnable;
79 this.proposedThreadName = proposedThreadName;
80 }
81
82 public void run() {
83 final Thread currentThread = Thread.currentThread();
84 final String oldThreadName = currentThread.getName();
85 final String newThreadName = getNewThreadName(oldThreadName);
86
87 // Change the thread name before starting the actual runnable.
88 boolean renamed = false;
89 if (!oldThreadName.equals(newThreadName)) {
90 try {
91 currentThread.setName(newThreadName);
92 renamed = true;
93 } catch (SecurityException e) {
94 logger.debug(
95 "Failed to rename a thread " +
96 "due to security restriction.", e);
97 }
98 }
99
100 // Run the actual runnable and revert the name back when it ends.
101 try {
102 runnable.run();
103 } finally {
104 if (renamed) {
105 // Revert the name back if the current thread was renamed.
106 // We do not check the exception here because we know it works.
107 currentThread.setName(oldThreadName);
108 }
109 }
110 }
111
112 private String getNewThreadName(String currentThreadName) {
113 String newThreadName = null;
114
115 try {
116 newThreadName =
117 getThreadNameDeterminer().determineThreadName(
118 currentThreadName, proposedThreadName);
119 } catch (Throwable t) {
120 logger.warn("Failed to determine the thread name", t);
121 }
122
123 return newThreadName == null? currentThreadName : newThreadName;
124 }
125 }