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1   /*
2    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3    *
4    * This code is free software; you can redistribute it and/or modify it
5    * under the terms of the GNU General Public License version 2 only, as
6    * published by the Free Software Foundation.  Oracle designates this
7    * particular file as subject to the "Classpath" exception as provided
8    * by Oracle in the LICENSE file that accompanied this code.
9    *
10   * This code is distributed in the hope that it will be useful, but WITHOUT
11   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
13   * version 2 for more details (a copy is included in the LICENSE file that
14   * accompanied this code).
15   *
16   * You should have received a copy of the GNU General Public License version
17   * 2 along with this work; if not, write to the Free Software Foundation,
18   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19   *
20   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21   * or visit www.oracle.com if you need additional information or have any
22   * questions.
23   */
24  
25  /*
26   * This file is available under and governed by the GNU General Public
27   * License version 2 only, as published by the Free Software Foundation.
28   * However, the following notice accompanied the original version of this
29   * file:
30   *
31   * Written by Doug Lea with assistance from members of JCP JSR-166
32   * Expert Group and released to the public domain, as explained at
33   * http://creativecommons.org/publicdomain/zero/1.0/
34   */
35  
36  package java.util.concurrent;
37  
38  /**
39   * An object that creates new threads on demand.  Using thread factories
40   * removes hardwiring of calls to {@link Thread#Thread(Runnable) new Thread},
41   * enabling applications to use special thread subclasses, priorities, etc.
42   *
43   * <p>
44   * The simplest implementation of this interface is just:
45   *  <pre> {@code
46   * class SimpleThreadFactory implements ThreadFactory {
47   *   public Thread newThread(Runnable r) {
48   *     return new Thread(r);
49   *   }
50   * }}</pre>
51   *
52   * The {@link Executors#defaultThreadFactory} method provides a more
53   * useful simple implementation, that sets the created thread context
54   * to known values before returning it.
55   * @since 1.5
56   * @author Doug Lea
57   */
58  public interface ThreadFactory {
59  
60      /**
61       * Constructs a new {@code Thread}.  Implementations may also initialize
62       * priority, name, daemon status, {@code ThreadGroup}, etc.
63       *
64       * @param r a runnable to be executed by new thread instance
65       * @return constructed thread, or {@code null} if the request to
66       *         create a thread is rejected
67       */
68      Thread newThread(Runnable r);
69  }