| /* |
| * Copyright (c) 2000, 2012, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #ifndef SHARE_VM_MEMORY_REFERENCEPOLICY_HPP |
| #define SHARE_VM_MEMORY_REFERENCEPOLICY_HPP |
| |
| // referencePolicy is used to determine when soft reference objects |
| // should be cleared. |
| |
| |
| class ReferencePolicy : public CHeapObj<mtGC> { |
| public: |
| virtual bool should_clear_reference(oop p, jlong timestamp_clock) { |
| ShouldNotReachHere(); |
| return true; |
| } |
| |
| // Capture state (of-the-VM) information needed to evaluate the policy |
| virtual void setup() { /* do nothing */ } |
| }; |
| |
| class NeverClearPolicy : public ReferencePolicy { |
| public: |
| virtual bool should_clear_reference(oop p, jlong timestamp_clock) { |
| return false; |
| } |
| }; |
| |
| class AlwaysClearPolicy : public ReferencePolicy { |
| public: |
| virtual bool should_clear_reference(oop p, jlong timestamp_clock) { |
| return true; |
| } |
| }; |
| |
| class LRUCurrentHeapPolicy : public ReferencePolicy { |
| private: |
| jlong _max_interval; |
| |
| public: |
| LRUCurrentHeapPolicy(); |
| |
| // Capture state (of-the-VM) information needed to evaluate the policy |
| void setup(); |
| virtual bool should_clear_reference(oop p, jlong timestamp_clock); |
| }; |
| |
| class LRUMaxHeapPolicy : public ReferencePolicy { |
| private: |
| jlong _max_interval; |
| |
| public: |
| LRUMaxHeapPolicy(); |
| |
| // Capture state (of-the-VM) information needed to evaluate the policy |
| void setup(); |
| virtual bool should_clear_reference(oop p, jlong timestamp_clock); |
| }; |
| |
| #endif // SHARE_VM_MEMORY_REFERENCEPOLICY_HPP |