1 /*
2 * Copyright (c) 2003, 2008, 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 java.lang.management;
27
28 /**
29 * The management interface for the operating system on which
30 * the Java virtual machine is running.
31 *
32 * <p> A Java virtual machine has a single instance of the implementation
33 * class of this interface. This instance implementing this interface is
34 * an <a href="ManagementFactory.html#MXBean">MXBean</a>
35 * that can be obtained by calling
36 * the {@link ManagementFactory#getOperatingSystemMXBean} method or
37 * from the {@link ManagementFactory#getPlatformMBeanServer
38 * platform MBeanServer} method.
39 *
40 * <p>The {@code ObjectName} for uniquely identifying the MXBean for
41 * the operating system within an MBeanServer is:
42 * <blockquote>
43 * {@link ManagementFactory#OPERATING_SYSTEM_MXBEAN_NAME
44 * java.lang:type=OperatingSystem}
45 * </blockquote>
46 *
47 * It can be obtained by calling the
48 * {@link PlatformManagedObject#getObjectName} method.
49 *
50 * <p> This interface defines several convenient methods for accessing
51 * system properties about the operating system on which the Java
52 * virtual machine is running.
53 *
54 * @see ManagementFactory#getPlatformMXBeans(Class)
55 * @see <a href="../../../javax/management/package-summary.html">
56 * JMX Specification.</a>
57 * @see <a href="package-summary.html#examples">
58 * Ways to Access MXBeans</a>
59 *
60 * @author Mandy Chung
61 * @since 1.5
62 */
63 public interface OperatingSystemMXBean extends PlatformManagedObject {
64 /**
65 * Returns the operating system name.
66 * This method is equivalent to {@code System.getProperty("os.name")}.
67 *
68 * @return the operating system name.
69 *
70 * @throws java.lang.SecurityException
71 * if a security manager exists and its
72 * <code>checkPropertiesAccess</code> method doesn't allow access
73 * to this system property.
74 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
75 * @see java.lang.System#getProperty
76 */
77 public String getName();
78
79 /**
80 * Returns the operating system architecture.
81 * This method is equivalent to {@code System.getProperty("os.arch")}.
82 *
83 * @return the operating system architecture.
84 *
85 * @throws java.lang.SecurityException
86 * if a security manager exists and its
87 * <code>checkPropertiesAccess</code> method doesn't allow access
88 * to this system property.
89 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
90 * @see java.lang.System#getProperty
91 */
92 public String getArch();
93
94 /**
95 * Returns the operating system version.
96 * This method is equivalent to {@code System.getProperty("os.version")}.
97 *
98 * @return the operating system version.
99 *
100 * @throws java.lang.SecurityException
101 * if a security manager exists and its
102 * <code>checkPropertiesAccess</code> method doesn't allow access
103 * to this system property.
104 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
105 * @see java.lang.System#getProperty
106 */
107 public String getVersion();
108
109 /**
110 * Returns the number of processors available to the Java virtual machine.
111 * This method is equivalent to the {@link Runtime#availableProcessors()}
112 * method.
113 * <p> This value may change during a particular invocation of
114 * the virtual machine.
115 *
116 * @return the number of processors available to the virtual
117 * machine; never smaller than one.
118 */
119 public int getAvailableProcessors();
120
121 /**
122 * Returns the system load average for the last minute.
123 * The system load average is the sum of the number of runnable entities
124 * queued to the {@linkplain #getAvailableProcessors available processors}
125 * and the number of runnable entities running on the available processors
126 * averaged over a period of time.
127 * The way in which the load average is calculated is operating system
128 * specific but is typically a damped time-dependent average.
129 * <p>
130 * If the load average is not available, a negative value is returned.
131 * <p>
132 * This method is designed to provide a hint about the system load
133 * and may be queried frequently.
134 * The load average may be unavailable on some platform where it is
135 * expensive to implement this method.
136 *
137 * @return the system load average; or a negative value if not available.
138 *
139 * @since 1.6
140 */
141 public double getSystemLoadAverage();
142 }