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 package com.oracle.java.testlibrary; 24 25 import com.sun.management.HotSpotDiagnosticMXBean; 26 import com.sun.management.VMOption; 27 import java.lang.management.ManagementFactory; 28 29 /** 30 * Simple class to check writability, invalid and valid values for VMOption 31 */ 32 public class DynamicVMOptionChecker { 33 34 /** 35 * Reads VM option from PlatformMXBean and parse it to integer value 36 * 37 * @param name of option 38 * @return parsed value 39 */ 40 public static int getIntValue(String name) { 41 42 VMOption option = ManagementFactory. 43 getPlatformMXBean(HotSpotDiagnosticMXBean.class). 44 getVMOption(name); 45 46 return Integer.parseInt(option.getValue()); 47 } 48 49 /** 50 * Sets VM option value 51 * 52 * @param name of option 53 * @param value to set 54 */ 55 public static void setIntValue(String name, int value) { 56 ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class).setVMOption(name, Integer.toString(value)); 57 } 58 59 /** 60 * Checks that VM option is dynamically writable 61 * 62 * @param name 63 * @throws RuntimeException if option if not writable 64 * @return always true 65 */ 66 public static boolean checkIsWritable(String name) { 67 VMOption option = ManagementFactory. 68 getPlatformMXBean(HotSpotDiagnosticMXBean.class). 69 getVMOption(name); 70 71 if (!option.isWriteable()) { 72 throw new RuntimeException(name + " is not writable"); 73 } 74 75 return true; 76 } 77 78 /** 79 * Checks that value cannot be set 80 * 81 * @param name of flag 82 * @param value string representation of value to set 83 * @throws RuntimeException on error - when expected exception hasn't been thrown 84 */ 85 public static void checkInvalidValue(String name, String value) { 86 // should throw 87 try { 88 ManagementFactory. 89 getPlatformMXBean(HotSpotDiagnosticMXBean.class). 90 setVMOption(name, value); 91 92 } catch (IllegalArgumentException e) { 93 return; 94 } 95 96 throw new RuntimeException("Expected IllegalArgumentException was not thrown, " + name + "= " + value); 97 } 98 99 /** 100 * Checks that value can be set 101 * 102 * @param name of flag to set 103 * @param value string representation of value to set 104 * @throws RuntimeException on error - when value in VM is not equal to origin 105 */ 106 public static void checkValidValue(String name, String value) { 107 ManagementFactory. 108 getPlatformMXBean(HotSpotDiagnosticMXBean.class). 109 setVMOption(name, value); 110 111 VMOption option = ManagementFactory. 112 getPlatformMXBean(HotSpotDiagnosticMXBean.class). 113 getVMOption(name); 114 115 if (!option.getValue().equals(value)) { 116 throw new RuntimeException("Actual value of " + name + " \"" + option.getValue() 117 + "\" not equal origin \"" + value + "\""); 118 } 119 } 120 121 }