104 lines
2.9 KiB
Java
104 lines
2.9 KiB
Java
/*
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* Copyright (c) 2016, 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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package sun.hotspot.gc;
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import java.util.ArrayList;
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import java.util.List;
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import sun.hotspot.WhiteBox;
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/**
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* API to obtain information about selected and supported Garbage Collectors
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* retrieved from the VM with the WhiteBox API.
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*/
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public enum GC {
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Serial(1),
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Parallel(2),
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ConcMarkSweep(4),
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G1(8);
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private static final GC CURRENT_GC;
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private static final int ALL_GC_CODES;
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private static final boolean IS_BY_ERGO;
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static {
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WhiteBox WB = WhiteBox.getWhiteBox();
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ALL_GC_CODES = WB.allSupportedGC();
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IS_BY_ERGO = WB.gcSelectedByErgo();
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int currentCode = WB.currentGC();
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GC tmp = null;
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for (GC gc: GC.values()) {
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if (gc.code == currentCode) {
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tmp = gc;
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break;
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}
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}
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if (tmp == null) {
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throw new Error("Unknown current GC code " + currentCode);
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}
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CURRENT_GC = tmp;
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}
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private final int code;
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private GC(int code) {
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this.code = code;
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}
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/**
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* @return true if the collector is supported by the VM, false otherwise.
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*/
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public boolean isSupported() {
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return (ALL_GC_CODES & code) != 0;
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}
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/**
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* @return the current collector used by VM.
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*/
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public static GC current() {
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return CURRENT_GC;
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}
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/**
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* @return true if GC was selected by ergonomic, false if specified
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* explicitly by the command line flag.
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*/
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public static boolean currentSetByErgo() {
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return IS_BY_ERGO;
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}
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/**
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* @return List of collectors supported by the VM.
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*/
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public static List<GC> allSupported() {
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List<GC> list = new ArrayList<>();
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for (GC gc: GC.values()) {
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if (gc.isSupported()) {
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list.add(gc);
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}
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}
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return list;
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}
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}
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