1 /*

     2  * Copyright (c) 2012, 2013, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 #include "precompiled.hpp"

    26 #include "runtime/atomic.inline.hpp"

    27 #include "services/memPtr.hpp"

    28 #include "services/memTracker.hpp"

    29 

    30 volatile jint SequenceGenerator::_seq_number = 1;

    31 volatile unsigned long SequenceGenerator::_generation = 1;

    32 NOT_PRODUCT(jint SequenceGenerator::_max_seq_number = 1;)

    33 

    34 jint SequenceGenerator::next() {

    35   jint seq = Atomic::add(1, &_seq_number);

    36   if (seq < 0) {

    37     MemTracker::shutdown(MemTracker::NMT_sequence_overflow);

    38   } else {

    39     NOT_PRODUCT(_max_seq_number = (seq > _max_seq_number) ? seq : _max_seq_number;)

    40   }

    41   return seq;

    42 }

    43