/*+
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 * Copyright (c) 2000, 2012, 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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+
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#ifndef SHARE_VM_MEMORY_REFERENCEPOLICY_HPP+
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#define SHARE_VM_MEMORY_REFERENCEPOLICY_HPP+
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+
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// referencePolicy is used to determine when soft reference objects+
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// should be cleared.+
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+
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+
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class ReferencePolicy : public CHeapObj<mtGC> {+
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 public:+
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  virtual bool should_clear_reference(oop p, jlong timestamp_clock) {+
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    ShouldNotReachHere();+
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    return true;+
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  }+
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+
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  // Capture state (of-the-VM) information needed to evaluate the policy+
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  virtual void setup() { /* do nothing */ }+
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};+
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+
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class NeverClearPolicy : public ReferencePolicy {+
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 public:+
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  virtual bool should_clear_reference(oop p, jlong timestamp_clock) {+
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    return false;+
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  }+
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};+
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+
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class AlwaysClearPolicy : public ReferencePolicy {+
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 public:+
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  virtual bool should_clear_reference(oop p, jlong timestamp_clock) {+
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    return true;+
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  }+
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};+
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+
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class LRUCurrentHeapPolicy : public ReferencePolicy {+
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 private:+
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  jlong _max_interval;+
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+
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 public:+
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  LRUCurrentHeapPolicy();+
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+
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  // Capture state (of-the-VM) information needed to evaluate the policy+
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  void setup();+
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  virtual bool should_clear_reference(oop p, jlong timestamp_clock);+
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};+
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+
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class LRUMaxHeapPolicy : public ReferencePolicy {+
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 private:+
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  jlong _max_interval;+
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+
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 public:+
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  LRUMaxHeapPolicy();+
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+
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  // Capture state (of-the-VM) information needed to evaluate the policy+
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  void setup();+
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  virtual bool should_clear_reference(oop p, jlong timestamp_clock);+
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};+
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+
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#endif // SHARE_VM_MEMORY_REFERENCEPOLICY_HPP+
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