/*

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

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

 *

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

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

 * published by the Free Software Foundation.

 *

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

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

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

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

 * accompanied this code).

 *

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

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

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

 *

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

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

 * have any questions.

 */

/*

 *

 *

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

 * TestThreadId.java

 */

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

// EG members and JUC list subscribers

import java.util.concurrent.atomic.AtomicInteger;

public class ThreadId {

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

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

    // Thread local variable containing each thread's ID

    private static final ThreadLocal<Integer> threadId =

        new ThreadLocal<Integer>() {

            @Override protected Integer initialValue() {

                return nextId.getAndIncrement();

        }

    };

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

    public static int get() {

        return threadId.get();

    }

}