/*+
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* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.+
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.+
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*+
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* This code is free software; you can redistribute it and/or modify it+
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* under the terms of the GNU General Public License version 2 only, as+
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* published by the Free Software Foundation.+
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*+
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* This code is distributed in the hope that it will be useful, but WITHOUT+
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or+
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* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License+
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* version 2 for more details (a copy is included in the LICENSE file that+
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* accompanied this code).+
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*+
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* You should have received a copy of the GNU General Public License version+
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* 2 along with this work; if not, write to the Free Software Foundation,+
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.+
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*+
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA+
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* or visit www.oracle.com if you need additional information or have any+
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* questions.+
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*/+
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+
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import java.lang.management.GarbageCollectorMXBean;+
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import java.lang.management.ManagementFactory;+
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import java.util.Arrays;+
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import java.util.Objects;+
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+
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/**+
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 * Helper class with enum representation of GC types.+
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 */+
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public final class GCTypes {+
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+
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    private static <T extends GCType> T getCurrentGCType(Class<T> type) {+
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        return ManagementFactory.getGarbageCollectorMXBeans().stream()+
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                .map(bean -> getGCTypeByName(type, bean.getName()))+
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                .filter(Objects::nonNull)+
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                .findFirst()+
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                .orElse(null);+
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    }+
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+
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    private static <T extends GCType> T getGCTypeByName(Class<T> type, String name) {+
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        return Arrays.stream(type.getEnumConstants())+
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                .filter(e -> e.getGCName().equals(name))+
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                .findFirst()+
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                .orElse(null);+
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    }+
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+
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    private static <T extends GCType> GarbageCollectorMXBean getGCBeanByType(Class<T> type) {+
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        return ManagementFactory.getGarbageCollectorMXBeans().stream()+
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                .filter(bean -> Arrays.stream(type.getEnumConstants())+
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                        .filter(enumName -> enumName.getGCName().equals(bean.getName()))+
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                        .findFirst()+
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                        .isPresent()+
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                )+
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                .findFirst()+
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                .orElse(null);+
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    }+
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+
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    /**+
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     * Helper interface used by GCTypes static methods+
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     * to get gcTypeName field of *GCType classes.+
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     */+
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    private interface GCType {+
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+
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        String getGCName();+
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    }+
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+
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    public static enum YoungGCType implements GCType {+
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        DefNew("Copy"),+
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        ParNew("ParNew"),+
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        PSNew("PS Scavenge"),+
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        G1("G1 Young Generation");+
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+
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        @Override+
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        public String getGCName() {+
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            return gcTypeName;+
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        }+
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        private final String gcTypeName;+
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+
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        private YoungGCType(String name) {+
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            gcTypeName = name;+
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        }+
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+
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        public static YoungGCType getYoungGCType() {+
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            return GCTypes.getCurrentGCType(YoungGCType.class);+
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        }+
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+
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        public static GarbageCollectorMXBean getYoungGCBean() {+
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            return GCTypes.getGCBeanByType(YoungGCType.class);+
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        }+
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    }+
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+
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    public static enum OldGCType implements GCType {+
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        Serial("MarkSweepCompact"),+
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        CMS("ConcurrentMarkSweep"),+
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        PSOld("PS MarkSweep"),+
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        G1("G1 Old Generation");+
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+
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        private final String gcTypeName;+
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+
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        private OldGCType(String name) {+
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            gcTypeName = name;+
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        }+
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+
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        public static OldGCType getOldGCType() {+
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            return GCTypes.getCurrentGCType(OldGCType.class);+
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        }+
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+
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        @Override+
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        public String getGCName() {+
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            return gcTypeName;+
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        }+
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    }+
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}+
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