1 /* 2 * Copyright (c) 2013, 2015, 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.lang.management.RuntimeMXBean; 25 import java.lang.management.ManagementFactory; 26 import java.util.List; 27 28 /** 29 * This class provides access to the input arguments to the VM. 30 */ 31 public class InputArguments { 32 private static final List<String> args; 33 34 static { 35 RuntimeMXBean runtimeMxBean = ManagementFactory.getRuntimeMXBean(); 36 args = runtimeMxBean.getInputArguments(); 37 } 38 39 /** 40 * Returns true if {@code arg} is an input argument to the VM. 41 * 42 * This is useful for checking boolean flags such as -XX:+UseSerialGC or 43 * -XX:-UsePerfData. 44 * 45 * @param arg The name of the argument. 46 * @return {@code true} if the given argument is an input argument, 47 * otherwise {@code false}. 48 */ 49 public static boolean contains(String arg) { 50 return args.contains(arg); 51 } 52 53 /** 54 * Returns true if {@code prefix} is the start of an input argument to the 55 * VM. 56 * 57 * This is useful for checking if flags describing a quantity, such as 58 * -XX:+MaxMetaspaceSize=100m, is set without having to know the quantity. 59 * To check if the flag -XX:MaxMetaspaceSize is set, use 60 * {@code InputArguments.containsPrefix("-XX:MaxMetaspaceSize")}. 61 * 62 * @param prefix The start of the argument. 63 * @return {@code true} if the given argument is the start of an input 64 * argument, otherwise {@code false}. 65 */ 66 public static boolean containsPrefix(String prefix) { 67 for (String arg : args) { 68 if (arg.startsWith(prefix)) { 69 return true; 70 } 71 } 72 return false; 73 } 74 }