001 /*
002 * Copyright 2003-2005 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package java.lang.management;
027
028 /**
029 * The management interface for the operating system on which
030 * the Java virtual machine is running.
031 *
032 * <p> A Java virtual machine has a single instance of the implementation
033 * class of this interface. This instance implementing this interface is
034 * an <a href="ManagementFactory.html#MXBean">MXBean</a>
035 * that can be obtained by calling
036 * the {@link ManagementFactory#getOperatingSystemMXBean} method or
037 * from the {@link ManagementFactory#getPlatformMBeanServer
038 * platform <tt>MBeanServer</tt>} method.
039 *
040 * <p>The <tt>ObjectName</tt> for uniquely identifying the MXBean for
041 * the operating system within an MBeanServer is:
042 * <blockquote>
043 * {@link ManagementFactory#OPERATING_SYSTEM_MXBEAN_NAME
044 * <tt>java.lang:type=OperatingSystem</tt>}
045 * </blockquote>
046 *
047 * <p> This interface defines several convenient methods for accessing
048 * system properties about the operating system on which the Java
049 * virtual machine is running.
050 *
051 * @see <a href="../../../javax/management/package-summary.html">
052 * JMX Specification.</a>
053 * @see <a href="package-summary.html#examples">
054 * Ways to Access MXBeans</a>
055 *
056 * @author Mandy Chung
057 * @version 1.17, 05/05/07
058 * @since 1.5
059 */
060 public interface OperatingSystemMXBean {
061 /**
062 * Returns the operating system name.
063 * This method is equivalent to <tt>System.getProperty("os.name")</tt>.
064 *
065 * @return the operating system name.
066 *
067 * @throws java.lang.SecurityException
068 * if a security manager exists and its
069 * <code>checkPropertiesAccess</code> method doesn't allow access
070 * to this system property.
071 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
072 * @see java.lang.System#getProperty
073 */
074 public String getName();
075
076 /**
077 * Returns the operating system architecture.
078 * This method is equivalent to <tt>System.getProperty("os.arch")</tt>.
079 *
080 * @return the operating system architecture.
081 *
082 * @throws java.lang.SecurityException
083 * if a security manager exists and its
084 * <code>checkPropertiesAccess</code> method doesn't allow access
085 * to this system property.
086 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
087 * @see java.lang.System#getProperty
088 */
089 public String getArch();
090
091 /**
092 * Returns the operating system version.
093 * This method is equivalent to <tt>System.getProperty("os.version")</tt>.
094 *
095 * @return the operating system version.
096 *
097 * @throws java.lang.SecurityException
098 * if a security manager exists and its
099 * <code>checkPropertiesAccess</code> method doesn't allow access
100 * to this system property.
101 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
102 * @see java.lang.System#getProperty
103 */
104 public String getVersion();
105
106 /**
107 * Returns the number of processors available to the Java virtual machine.
108 * This method is equivalent to the {@link Runtime#availableProcessors()}
109 * method.
110 * <p> This value may change during a particular invocation of
111 * the virtual machine.
112 *
113 * @return the number of processors available to the virtual
114 * machine; never smaller than one.
115 */
116 public int getAvailableProcessors();
117
118 /**
119 * Returns the system load average for the last minute.
120 * The system load average is the sum of the number of runnable entities
121 * queued to the {@linkplain #getAvailableProcessors available processors}
122 * and the number of runnable entities running on the available processors
123 * averaged over a period of time.
124 * The way in which the load average is calculated is operating system
125 * specific but is typically a damped time-dependent average.
126 * <p>
127 * If the load average is not available, a negative value is returned.
128 * <p>
129 * This method is designed to provide a hint about the system load
130 * and may be queried frequently.
131 * The load average may be unavailable on some platform where it is
132 * expensive to implement this method.
133 *
134 * @return the system load average; or a negative value if not available.
135 *
136 * @since 1.6
137 */
138 public double getSystemLoadAverage();
139 }
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