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1 /*
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2 * Copyright 2000 Sun Microsystems, Inc. All Rights Reserved.
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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4 *
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5 * This code is free software; you can redistribute it and/or modify it
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6 * under the terms of the GNU General Public License version 2 only, as
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7 * published by the Free Software Foundation.
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8 *
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9 * This code is distributed in the hope that it will be useful, but WITHOUT
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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12 * version 2 for more details (a copy is included in the LICENSE file that
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13 * accompanied this code).
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14 *
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15 * You should have received a copy of the GNU General Public License version
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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18 *
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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20 * CA 95054 USA or visit www.sun.com if you need additional information or
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21 * have any questions.
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22 *
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23 */
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24
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25 // referencePolicy is used to determine when soft reference objects
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26 // should be cleared.
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27
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28
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29 class ReferencePolicy : public ResourceObj {
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30 public:
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31 virtual bool should_clear_reference(oop p) { ShouldNotReachHere(); return true; }
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32 };
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33
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34 class NeverClearPolicy : public ReferencePolicy {
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35 public:
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36 bool should_clear_reference(oop p) { return false; }
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37 };
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38
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39 class AlwaysClearPolicy : public ReferencePolicy {
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40 public:
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41 bool should_clear_reference(oop p) { return true; }
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42 };
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43
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44 class LRUCurrentHeapPolicy : public ReferencePolicy {
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45 private:
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46 jlong _max_interval;
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47
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48 public:
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49 LRUCurrentHeapPolicy();
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50
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51 bool should_clear_reference(oop p);
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52 };
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53
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54 class LRUMaxHeapPolicy : public ReferencePolicy {
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55 private:
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56 jlong _max_interval;
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57
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58 public:
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59 LRUMaxHeapPolicy();
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60
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61 bool should_clear_reference(oop p);
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62 };
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