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 class loading system of
  30  * the Java virtual machine.
  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#getClassLoadingMXBean} method or
  37  * from the {@link ManagementFactory#getPlatformMBeanServer
  38  * platform <tt>MBeanServer</tt>}.
  39  *
  40  * <p>The <tt>ObjectName</tt> for uniquely identifying the MXBean for
  41  * the class loading system within an <tt>MBeanServer</tt> is:
  42  * <blockquote>
  43  * {@link ManagementFactory#CLASS_LOADING_MXBEAN_NAME
  44  *        <tt>java.lang:type=ClassLoading</tt>}
  45  * </blockquote>
  46  *
  47  * It can be obtained by calling the
  48  * {@link PlatformManagedObject#getObjectName} method.
  49  *
  50  * @see ManagementFactory#getPlatformMXBeans(Class)
  51  * @see <a href="../../../javax/management/package-summary.html">
  52  *      JMX Specification.</a>
  53  * @see <a href="package-summary.html#examples">
  54  *      Ways to Access MXBeans</a>
  55  *
  56  * @author  Mandy Chung
  57  * @since   1.5
  58  */
  59 public interface ClassLoadingMXBean extends PlatformManagedObject {
  60 
  61     /**
  62      * Returns the total number of classes that have been loaded since
  63      * the Java virtual machine has started execution.
  64      *
  65      * @return the total number of classes loaded.
  66      *
  67      */
  68     public long getTotalLoadedClassCount();
  69 
  70     /**
  71      * Returns the number of classes that are currently loaded in the
  72      * Java virtual machine.
  73      *
  74      * @return the number of currently loaded classes.
  75      */
  76     public int getLoadedClassCount();
  77 
  78     /**
  79      * Returns the total number of classes unloaded since the Java virtual machine
  80      * has started execution.
  81      *
  82      * @return the total number of unloaded classes.
  83      */
  84     public long getUnloadedClassCount();
  85 
  86     /**
  87      * Tests if the verbose output for the class loading system is enabled.
  88      *
  89      * @return <tt>true</tt> if the verbose output for the class loading
  90      * system is enabled; <tt>false</tt> otherwise.
  91      */
  92     public boolean isVerbose();
  93 
  94     /**
  95      * Enables or disables the verbose output for the class loading
  96      * system.  The verbose output information and the output stream
  97      * to which the verbose information is emitted are implementation
  98      * dependent.  Typically, a Java virtual machine implementation
  99      * prints a message each time a class file is loaded.
 100      *
 101      * <p>This method can be called by multiple threads concurrently.
 102      * Each invocation of this method enables or disables the verbose
 103      * output globally.
 104      *
 105      * @param value <tt>true</tt> to enable the verbose output;
 106      *              <tt>false</tt> to disable.
 107      *
 108      * @exception  java.lang.SecurityException if a security manager
 109      *             exists and the caller does not have
 110      *             ManagementPermission("control").
 111      */
 112     public void setVerbose(boolean value);
 113 
 114 }