Mercurial > hg > graal-compiler
view test/testlibrary/com/oracle/java/testlibrary/DynamicVMOption.java @ 22232:4a500b3783fb
Merge
author | Tom Rodriguez <tom.rodriguez@oracle.com> |
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date | Wed, 15 Jul 2015 10:16:28 -0700 |
parents | e2976043eac3 |
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/* * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.oracle.java.testlibrary; import com.sun.management.HotSpotDiagnosticMXBean; import java.lang.management.ManagementFactory; /** * A utility class to work with VM options which could be altered during * execution. * * This class is a wrapper around {@code com.sun.management.VMOption}. * It provides more convenient interface to read/write the values. * */ public class DynamicVMOption { private final HotSpotDiagnosticMXBean mxBean; /** * VM option name, like "MinHeapFreeRatio". */ public final String name; /** * Creates an instance of DynamicVMOption. * * @param name the VM option name */ public DynamicVMOption(String name) { this.name = name; mxBean = ManagementFactory.getPlatformMXBean(HotSpotDiagnosticMXBean.class); } /** * Sets a new value for the option. * Trying to set not applicable value will cause IllegalArgumentException. * Behavior with null is undefined, most likely NPE will be thrown. * * @param newValue the value to be set * @see #getValue() * @throws IllegalArgumentException if newValue is not applicable to the option */ public final void setValue(String newValue) { mxBean.setVMOption(name, newValue); } /** * Returns the value of option. * * @return the current option value * @see #setValue(java.lang.String) */ public final String getValue() { return mxBean.getVMOption(name).getValue(); } /** * Returns true, if option is writable, false otherwise. * * @return true, if option is writable, false otherwise */ public final boolean isWriteable() { return mxBean.getVMOption(name).isWriteable(); } /** * Checks if the given value is applicable for the option. * * This method tries to set the option to the new value. If no exception * has been thrown the value is treated as valid. * * Calling this method will not change the option value. After an attempt * to set a new value, the option will be restored to its previous value. * * @param value the value to verify * @return true if option could be set to the given value */ public boolean isValidValue(String value) { boolean isValid = true; String oldValue = getValue(); try { setValue(value); } catch (NullPointerException e) { if (value == null) { isValid = false; } } catch (IllegalArgumentException e) { isValid = false; } finally { setValue(oldValue); } return isValid; } /** * Returns the value of the given VM option as String. * * This is a simple shortcut for {@code new DynamicVMOption(name).getValue()} * * @param name the name of VM option * @return value as a string * @see #getValue() */ public static String getString(String name) { return new DynamicVMOption(name).getValue(); } /** * Returns the value of the given option as int. * * @param name the name of VM option * @return value parsed as integer * @see #getString(java.lang.String) * */ public static int getInt(String name) { return Integer.parseInt(getString(name)); } /** * Sets the VM option to a new value. * * This is a simple shortcut for {@code new DynamicVMOption(name).setValue(value)} * * @param name the name of VM option * @param value the value to be set * @see #setValue(java.lang.String) */ public static void setString(String name, String value) { new DynamicVMOption(name).setValue(value); } /** * Sets the VM option value to a new integer value. * * @param name the name of VM option * @param value the integer value to be set * @see #setString(java.lang.String, java.lang.String) */ public static void setInt(String name, int value) { new DynamicVMOption(name).setValue(Integer.toString(value)); } }