1 /*
2 * Copyright 2009 Red Hat, Inc.
3 *
4 * Red Hat licenses this file to you under the Apache License, version 2.0
5 * (the "License"); you may not use this file except in compliance with the
6 * 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 * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
28 * @author <a href="http://gleamynode.net/">Trustin Lee</a>
29 *
30 * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $
31 *
32 * @apiviz.landmark
33 * @apiviz.has org.jboss.netty.util.ThreadNameDeterminer oneway - -
34 *
35 */
36 public class ThreadRenamingRunnable implements Runnable {
37
38 private static final InternalLogger logger =
39 InternalLoggerFactory.getInstance(ThreadRenamingRunnable.class);
40
41 private static volatile ThreadNameDeterminer threadNameDeterminer =
42 ThreadNameDeterminer.PROPOSED;
43
44 /**
45 * Returns the {@link ThreadNameDeterminer} which overrides the proposed
46 * new thread name.
47 */
48 public static ThreadNameDeterminer getThreadNameDeterminer() {
49 return threadNameDeterminer;
50 }
51
52 /**
53 * Sets the {@link ThreadNameDeterminer} which overrides the proposed new
54 * thread name. Please note that the specified {@link ThreadNameDeterminer}
55 * affects only new {@link ThreadRenamingRunnable}s; the existing instances
56 * are not affected at all. Therefore, you should make sure to call this
57 * method at the earliest possible point (i.e. before any Netty worker
58 * thread starts) for consistent thread naming. Otherwise, you might see
59 * the default thread names and the new names appear at the same time in
60 * the full thread dump.
61 */
62 public static void setThreadNameDeterminer(ThreadNameDeterminer threadNameDeterminer) {
63 if (threadNameDeterminer == null) {
64 throw new NullPointerException("threadNameDeterminer");
65 }
66 ThreadRenamingRunnable.threadNameDeterminer = threadNameDeterminer;
67 }
68
69 private final Runnable runnable;
70 private final String proposedThreadName;
71
72 /**
73 * Creates a new instance which wraps the specified {@code runnable}
74 * and changes the thread name to the specified thread name when the
75 * specified {@code runnable} is running.
76 */
77 public ThreadRenamingRunnable(Runnable runnable, String proposedThreadName) {
78 if (runnable == null) {
79 throw new NullPointerException("runnable");
80 }
81 if (proposedThreadName == null) {
82 throw new NullPointerException("proposedThreadName");
83 }
84 this.runnable = runnable;
85 this.proposedThreadName = proposedThreadName;
86 }
87
88 public void run() {
89 final Thread currentThread = Thread.currentThread();
90 final String oldThreadName = currentThread.getName();
91 final String newThreadName = getNewThreadName(oldThreadName);
92
93 // Change the thread name before starting the actual runnable.
94 boolean renamed = false;
95 if (!oldThreadName.equals(newThreadName)) {
96 try {
97 currentThread.setName(newThreadName);
98 renamed = true;
99 } catch (SecurityException e) {
100 logger.debug(
101 "Failed to rename a thread " +
102 "due to security restriction.", e);
103 }
104 }
105
106 // Run the actual runnable and revert the name back when it ends.
107 try {
108 runnable.run();
109 } finally {
110 if (renamed) {
111 // Revert the name back if the current thread was renamed.
112 // We do not check the exception here because we know it works.
113 currentThread.setName(oldThreadName);
114 }
115 }
116 }
117
118 private String getNewThreadName(String currentThreadName) {
119 String newThreadName = null;
120
121 try {
122 newThreadName =
123 getThreadNameDeterminer().determineThreadName(
124 currentThreadName, proposedThreadName);
125 } catch (Throwable t) {
126 logger.warn("Failed to determine the thread name", t);
127 }
128
129 return newThreadName == null? currentThreadName : newThreadName;
130 }
131 }