001/* ClassLoadingMXBean.java - Interface for a class loading 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 class loading
042 * behaviour of the current invocation of the virtual
043 * machine.  An instance of this bean is obtained by calling
044 * {@link ManagementFactory#getClassLoadingMXBean()}.
045 *
046 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
047 * @since 1.5
048 */
049public interface ClassLoadingMXBean
050{
051
052  /**
053   * Returns the number of classes currently loaded by
054   * the virtual machine.
055   *
056   * @return the number of loaded classes.
057   */
058  int getLoadedClassCount();
059
060  /**
061   * Returns the total number of classes loaded by the
062   * virtual machine since it was started.  This is the
063   * sum of the currently loaded classes and those that
064   * have been unloaded.
065   *
066   * @return the total number of classes that have been
067   *         loaded by the virtual machine since it started.
068   */
069  long getTotalLoadedClassCount();
070
071  /**
072   * Returns the number of classes that have been unloaded
073   * by the virtual machine since it was started.
074   *
075   * @return the number of unloaded classes.
076   */
077  long getUnloadedClassCount();
078
079  /**
080   * Returns true if the virtual machine will emit additional
081   * information when classes are loaded and unloaded.  The
082   * format of the output is left up to the virtual machine.
083   *
084   * @return true if verbose class loading output is on.
085   */
086  boolean isVerbose();
087
088  /**
089   * Turns on or off the emission of additional information
090   * when classes are loaded and unloaded.  The format of the
091   * output is left up to the virtual machine.  This method
092   * may be called by multiple threads concurrently, but there
093   * is only one global setting of verbosity that is affected.
094   *
095   * @param verbose the new setting for verbose class loading
096   *                output.
097   * @throws SecurityException if a security manager exists and
098   *                           denies ManagementPermission("control").
099   */
100  void setVerbose(boolean verbose);
101
102}