001 /* ClassLoadingMXBean.java - Interface for a class loading bean
002 Copyright (C) 2006 Free Software Foundation
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038 package 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 */
049 public 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 }