001/* OperatingSystemMXBean.java - Interface for an operating system bean
002   Copyright (C) 2006 Free Software Foundation
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038package java.lang.management;
039
040/**
041 * Provides access to information about the underlying operating
042 * system.  An instance of this bean is obtained by calling
043 * {@link ManagementFactory#getOperatingSystemMXBean()}.
044 *
045 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
046 * @since 1.5
047 */
048public interface OperatingSystemMXBean
049{
050
051  /**
052   * Returns the name of the underlying system architecture.  This
053   * is equivalent to obtaining the <code>os.arch</code> property
054   * via {@link System#getProperty(String)}.
055   *
056   * @return the name of the underlying system architecture on which
057   *         the VM is running.
058   * @throws SecurityException if a security manager exists which
059   *                           prevents access to the name property.
060   * @see java.lang.System#getProperty(String)
061   * @see java.lang.SecurityManager#checkPropertyAccess(String)
062   */
063  String getArch();
064
065  /**
066   * Returns the number of processors currently available to the
067   * virtual machine.  This number is subject to change during
068   * execution of the virtual machine, and will always be >= 1.
069   * The call is equivalent to {@link Runtime#availableProcessors()}.
070   *
071   * @return the number of processors available to the VM.
072   */
073  int getAvailableProcessors();
074
075  /**
076   * Returns the name of the underlying operating system.  This
077   * is equivalent to obtaining the <code>os.name</code> property
078   * via {@link System#getProperty(String)}.
079   *
080   * @return the name of the operating system on which the VM
081   *         is running.
082   * @throws SecurityException if a security manager exists which
083   *                           prevents access to the name property.
084   * @see java.lang.System#getProperty(String)
085   * @see java.lang.SecurityManager#checkPropertyAccess(String)
086   */
087  String getName();
088
089  /**
090   * Returns the system load average for the last minute, or -1
091   * if this is unavailable.  The availability and calculation
092   * of the load average is system-dependent, but is usually
093   * a damped time-dependent average obtained by monitoring the
094   * number of queued and running processes.  It is expected
095   * that this method will be called frequently to monitor the
096   * average over time, so it may not be implemented on systems
097   * where such a call is expensive.
098   *
099   * @return the system load average for the last minute, or -1
100   *         if this is unavailable.
101   * @since 1.6
102   */
103  double getSystemLoadAverage();
104
105  /**
106   * Returns the version of the underlying operating system.  This
107   * is equivalent to obtaining the <code>os.version</code> property
108   * via {@link System#getProperty(String)}.
109   *
110   * @return the version of the operating system on which the VM
111   *         is running.
112   * @throws SecurityException if a security manager exists which
113   *                           prevents access to the name property.
114   * @see java.lang.System#getProperty(String)
115   * @see java.lang.SecurityManager#checkPropertyAccess(String)
116   */
117  String getVersion();
118
119}