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 writeability, 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 * Checks that VM option is dynamically writable 51 * 52 * @param name 53 * @throws RuntimeException if option if not writable 54 * @return always true 55 */ 56 public static boolean checkIsWritable(String name) { 57 VMOption option = ManagementFactory. 58 getPlatformMXBean(HotSpotDiagnosticMXBean.class). 59 getVMOption(name); 60 61 if (!option.isWriteable()) { 62 throw new RuntimeException(name + " is not writable"); 63 } 64 65 return true; 66 } 67 68 /** 69 * Checks that value cannot be set 70 * 71 * @param name of flag 72 * @param value string representation of value to set 73 * @throws RuntimeException on error - when expected exception hasn't been thrown 74 */ 75 public static void checkInvalidValue(String name, String value) { 76 // should throw 77 try { 78 ManagementFactory. 79 getPlatformMXBean(HotSpotDiagnosticMXBean.class). 80 setVMOption(name, value); 81 82 } catch (IllegalArgumentException e) { 83 return; 84 } 85 86 throw new RuntimeException("Expected IllegalArgumentException was not thrown, " + name + "= " + value); 87 } 88 89 /** 90 * Checks that value can be set 91 * 92 * @param name of flag to set 93 * @param value string representation of value to set 94 * @throws RuntimeException on error - when value in VM is not equal to origin 95 */ 96 public static void checkValidValue(String name, String value) { 97 ManagementFactory. 98 getPlatformMXBean(HotSpotDiagnosticMXBean.class). 99 setVMOption(name, value); 100 101 VMOption option = ManagementFactory. 102 getPlatformMXBean(HotSpotDiagnosticMXBean.class). 103 getVMOption(name); 104 105 if (!option.getValue().equals(value)) { 106 throw new RuntimeException("Actual value of " + name + " \"" + option.getValue() 107 + "\" not equal origin \"" + value + "\""); 108 } 109 } 110 111 }