1 /* 2 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 import java.util.Objects; 25 import java.util.function.BiConsumer; 26 import java.util.function.Function; 27 import jdk.testlib.WhiteBox; 28 import sun.management.*; 29 import com.sun.management.*; 30 import com.oracle.java.testlibrary.*; 31 32 public final class VmFlagTest<T> { 33 public static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox(); 34 35 private static final String NONEXISTENT_FLAG = "NonexistentFlag"; 36 private final String flagName; 37 private final BiConsumer<T, T> test; 38 private final BiConsumer<String, T> set; 39 private final Function<String, T> get; 40 private final boolean isPositive; 41 42 protected VmFlagTest(String flagName, BiConsumer<String, T> set, 43 Function<String, T> get, boolean isPositive) { 44 this.flagName = flagName; 45 this.set = set; 46 this.get = get; 47 this.isPositive = isPositive; 48 if (isPositive) { 49 test = this::testWritePositive; 50 } else { 51 test = this::testWriteNegative; 52 } 53 } 54 55 private void setNewValue(T value) { 56 set.accept(flagName, value); 57 } 58 59 private T getValue() { 60 return get.apply(flagName); 61 } 62 63 protected static <T> void runTest(String existentFlag, T[] tests, 64 BiConsumer<String, T> set, Function<String, T> get) { 65 runTest(existentFlag, tests, tests, set, get); 66 } 67 68 protected static <T> void runTest(String existentFlag, Function<String, T> get) { 69 runTest(existentFlag, null, null, null, get); 70 } 71 72 protected static <T> void runTest(String existentFlag, T[] tests, 73 T[] results, BiConsumer<String, T> set, Function<String, T> get) { 74 if (existentFlag != null) { 75 new VmFlagTest(existentFlag, set, get, true).test(tests, results); 76 } 77 new VmFlagTest(NONEXISTENT_FLAG, set, get, false).test(tests, results); 78 } 79 80 public final void test(T[] tests, T[] results) { 81 if (isPositive) { 82 testRead(); 83 } 84 if (tests != null) { 85 Asserts.assertEQ(tests.length, results.length, "[TESTBUG] tests.length != results.length"); 86 for (int i = 0, n = tests.length ; i < n; ++i) { 87 test.accept(tests[i], results[i]); 88 } 89 } 90 } 91 92 protected String getVMOptionAsString() { 93 if (WHITE_BOX.isConstantVMFlag(flagName) || WHITE_BOX.isLockedVMFlag(flagName)) { 94 // JMM cannot access debug flags in product builds or locked flags, 95 // use whitebox methods to get such flags value. 96 return asString(getValue()); 97 } 98 HotSpotDiagnosticMXBean diagnostic 99 = ManagementFactoryHelper.getDiagnosticMXBean(); 100 VMOption tmp; 101 try { 102 tmp = diagnostic.getVMOption(flagName); 103 } catch (IllegalArgumentException e) { 104 tmp = null; 105 } 106 return tmp == null ? null : tmp.getValue(); 107 } 108 109 private String testRead() { 110 String value = getVMOptionAsString(); 111 Asserts.assertNotNull(value); 112 Asserts.assertEQ(value, asString(getValue())); 113 Asserts.assertEQ(value, asString(WHITE_BOX.getVMFlag(flagName))); 114 return value; 115 } 116 117 private void testWritePositive(T value, T expected) { 118 setNewValue(value); 119 String newValue = testRead(); 120 Asserts.assertEQ(newValue, asString(expected)); 121 } 122 123 private void testWriteNegative(T value, T expected) { 124 // Should always return false for non-existing flags 125 Asserts.assertFalse(WHITE_BOX.isConstantVMFlag(flagName)); 126 Asserts.assertFalse(WHITE_BOX.isLockedVMFlag(flagName)); 127 String oldValue = getVMOptionAsString(); 128 Asserts.assertEQ(oldValue, asString(getValue())); 129 Asserts.assertEQ(oldValue, asString(WHITE_BOX.getVMFlag(flagName))); 130 setNewValue(value); 131 String newValue = getVMOptionAsString(); 132 Asserts.assertEQ(oldValue, newValue); 133 } 134 135 private String asString(Object value) { 136 return value == null ? null : "" + value; 137 } 138 }