/*

 * Copyright (c) 2003, 2008, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package java.lang.management;

/**

 * The management interface for the garbage collection of

 * the Java virtual machine.  Garbage collection is the process

 * that the Java virtual machine uses to find and reclaim unreachable

 * objects to free up memory space.  A garbage collector is one type of

 * {@link MemoryManagerMXBean memory manager}.

 *

 * <p> A Java virtual machine may have one or more instances of

 * the implementation class of this interface.

 * An instance implementing this interface is

 * an <a href="ManagementFactory.html#MXBean">MXBean</a>

 * that can be obtained by calling

 * the {@link ManagementFactory#getGarbageCollectorMXBeans} method or

 * from the {@link ManagementFactory#getPlatformMBeanServer

 * platform <tt>MBeanServer</tt>} method.

 *

 * <p>The <tt>ObjectName</tt> for uniquely identifying the MXBean for

 * a garbage collector within an MBeanServer is:

 * <blockquote>

 *   {@link ManagementFactory#GARBAGE_COLLECTOR_MXBEAN_DOMAIN_TYPE

 *    <tt>java.lang:type=GarbageCollector</tt>}<tt>,name=</tt><i>collector's name</i>

 * </blockquote>

 *

 * It can be obtained by calling the

 * {@link PlatformManagedObject#getObjectName} method.

 *

 * A platform usually includes additional platform-dependent information

 * specific to a garbage collection algorithm for monitoring.

 *

 * @see ManagementFactory#getPlatformMXBeans(Class)

 * @see MemoryMXBean

 *

 * @see <a href="../../../javax/management/package-summary.html">

 *      JMX Specification.</a>

 * @see <a href="package-summary.html#examples">

 *      Ways to Access MXBeans</a>

 *

 * @author  Mandy Chung

 * @since   1.5

 */

public interface GarbageCollectorMXBean extends MemoryManagerMXBean {

    /**

     * Returns the total number of collections that have occurred.

     * This method returns <tt>-1</tt> if the collection count is undefined for

     * this collector.

     *

     * @return the total number of collections that have occurred.

     */

    public long getCollectionCount();

    /**

     * Returns the approximate accumulated collection elapsed time

     * in milliseconds.  This method returns <tt>-1</tt> if the collection

     * elapsed time is undefined for this collector.

     * <p>

     * The Java virtual machine implementation may use a high resolution

     * timer to measure the elapsed time.  This method may return the

     * same value even if the collection count has been incremented

     * if the collection elapsed time is very short.

     *

     * @return the approximate accumulated collection elapsed time

     * in milliseconds.

     */

    public long getCollectionTime();

}