1/*
2 * Copyright (c) 2003, 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.  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
26package com.sun.management.internal;
27
28import java.util.*;
29import com.sun.management.VMOption;
30import com.sun.management.VMOption.Origin;
31import 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 */
39class 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}
130