01 /*
02 * Copyright 2003-2004 Sun Microsystems, Inc. All Rights Reserved.
03 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
04 *
05 * This code is free software; you can redistribute it and/or modify it
06 * under the terms of the GNU General Public License version 2 only, as
07 * published by the Free Software Foundation. Sun designates this
08 * particular file as subject to the "Classpath" exception as provided
09 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.lang.management;
27
28 /**
29 * The management interface for the garbage collection of
30 * the Java virtual machine. Garbage collection is the process
31 * that the Java virtual machine uses to find and reclaim unreachable
32 * objects to free up memory space. A garbage collector is one type of
33 * {@link MemoryManagerMXBean memory manager}.
34 *
35 * <p> A Java virtual machine may have one or more instances of
36 * the implementation class of this interface.
37 * An instance implementing this interface is
38 * an <a href="ManagementFactory.html#MXBean">MXBean</a>
39 * that can be obtained by calling
40 * the {@link ManagementFactory#getGarbageCollectorMXBeans} method or
41 * from the {@link ManagementFactory#getPlatformMBeanServer
42 * platform <tt>MBeanServer</tt>} method.
43 *
44 * <p>The <tt>ObjectName</tt> for uniquely identifying the MXBean for
45 * a garbage collector within an MBeanServer is:
46 * <blockquote>
47 * {@link ManagementFactory#GARBAGE_COLLECTOR_MXBEAN_DOMAIN_TYPE
48 * <tt>java.lang:type=GarbageCollector</tt>}<tt>,name=</tt><i>collector's name</i>
49 * </blockquote>
50 *
51 * A platform usually includes additional platform-dependent information
52 * specific to a garbage collection algorithm for monitoring.
53 *
54 * @see MemoryMXBean
55 *
56 * @see <a href="../../../javax/management/package-summary.html">
57 * JMX Specification.</a>
58 * @see <a href="package-summary.html#examples">
59 * Ways to Access MXBeans</a>
60 *
61 * @author Mandy Chung
62 * @version 1.16, 05/05/07
63 * @since 1.5
64 */
65 public interface GarbageCollectorMXBean extends MemoryManagerMXBean {
66 /**
67 * Returns the total number of collections that have occurred.
68 * This method returns <tt>-1</tt> if the collection count is undefined for
69 * this collector.
70 *
71 * @return the total number of collections that have occurred.
72 */
73 public long getCollectionCount();
74
75 /**
76 * Returns the approximate accumulated collection elapsed time
77 * in milliseconds. This method returns <tt>-1</tt> if the collection
78 * elapsed time is undefined for this collector.
79 * <p>
80 * The Java virtual machine implementation may use a high resolution
81 * timer to measure the elapsed time. This method may return the
82 * same value even if the collection count has been incremented
83 * if the collection elapsed time is very short.
84 *
85 * @return the approximate accumulated collection elapsed time
86 * in milliseconds.
87 */
88 public long getCollectionTime();
89
90 }
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