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      * 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 }