1 /*

     2  * Copyright 2007 Sun Microsystems, Inc.  All Rights Reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  */

    23 

    24 /*

    25  *

    26  *

    27  * Example class from java.lang.ThreadLocal class doc. Used by

    28  * TestThreadId.java

    29  */

    30 

    31 // Josh Bloch suggested this latest version after many inputs from other

    32 // EG members and JUC list subscribers

    33 

    34 import java.util.concurrent.atomic.AtomicInteger;

    35 

    36 public class ThreadId {

    37     // Atomic integer containing the next thread ID to be assigned

    38     private static final AtomicInteger nextId = new AtomicInteger(0);

    39 

    40     // Thread local variable containing each thread's ID

    41     private static final ThreadLocal<Integer> threadId =

    42         new ThreadLocal<Integer>() {

    43             @Override protected Integer initialValue() {

    44                 return nextId.getAndIncrement();

    45         }

    46     };

    47 

    48     // Returns the current thread's unique ID, assigning it if necessary

    49     public static int get() {

    50         return threadId.get();

    51     }

    52 }