1 /*

     2  * Copyright (c) 2003, 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.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package sun.management;

    27 

    28 import java.util.*;

    29 import com.sun.management.VMOption;

    30 import com.sun.management.VMOption.Origin;

    31 import java.security.AccessController;

    32 

    33 /**

    34  * Flag class is a helper class for constructing a VMOption.

    35  * It has the static methods for getting the Flag objects, each

    36  * corresponds to one VMOption.

    37  *

    38  */

    39 class Flag {

    40     private String name;

    41     private Object value;

    42     private Origin origin;

    43     private boolean writeable;

    44     private boolean external;

    45 

    46     Flag(String name, Object value, boolean writeable,

    47          boolean external, Origin origin) {

    48         this.name = name;

    49         this.value = value == null ? "" : value ;

    50         this.origin = origin;

    51         this.writeable = writeable;

    52         this.external = external;

    53     }

    54 

    55     Object getValue() {

    56         return value;

    57     }

    58 

    59     boolean isWriteable() {

    60         return writeable;

    61     }

    62 

    63     boolean isExternal() {

    64         return external;

    65     }

    66 

    67     VMOption getVMOption() {

    68         return new VMOption(name, value.toString(), writeable, origin);

    69     }

    70 

    71     static Flag getFlag(String name) {

    72         String[] names = new String[1];

    73         names[0] = name;

    74 

    75         List<Flag> flags = getFlags(names, 1);

    76         if (flags.isEmpty()) {

    77             return null;

    78         } else {

    79             // flags should have only one element

    80             return flags.get(0);

    81         }

    82     }

    83 

    84     static List<Flag> getAllFlags() {

    85         int numFlags = getInternalFlagCount();

    86 

    87         // Get all internal flags with names = null

    88         return getFlags(null, numFlags);

    89     }

    90 

    91     private static List<Flag> getFlags(String[] names, int numFlags) {

    92         Flag[] flags = new Flag[numFlags];

    93         int count = getFlags(names, flags, numFlags);

    94 

    95         List<Flag> result = new ArrayList<>();

    96         for (Flag f : flags) {

    97             if (f != null) {

    98                 result.add(f);

    99             }

   100         }

   101         return result;

   102     }

   103 

   104     private static native String[] getAllFlagNames();

   105     // getFlags sets each element in the given flags array

   106     // with a Flag object only if the name is valid and the

   107     // type is supported. The flags array may contain null elements.

   108     private static native int getFlags(String[] names, Flag[] flags, int count);

   109     private static native int getInternalFlagCount();

   110 

   111     // These set* methods are synchronized on the class object

   112     // to avoid multiple threads updating the same flag at the same time.

   113     static synchronized native void setLongValue(String name, long value);

   114     static synchronized native void setDoubleValue(String name, double value);

   115     static synchronized native void setBooleanValue(String name, boolean value);

   116     static synchronized native void setStringValue(String name, String value);

   117 

   118     static {

   119         AccessController.doPrivileged(

   120             new java.security.PrivilegedAction<Void>() {

   121                 public Void run() {

   122                     System.loadLibrary("management");

   123                     return null;

   124                 }

   125             });

   126         initialize();

   127     }

   128     private static native void initialize();

   129 }