1 /* 2 * Copyright (c) 2007, 2011, 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 a buffer pool, for example a pool of 30 * {@link java.nio.ByteBuffer#allocateDirect direct} or {@link 31 * java.nio.MappedByteBuffer mapped} buffers. 32 * 33 * <p> A class implementing this interface is an 34 * {@link javax.management.MXBean}. A Java 35 * virtual machine has one or more implementations of this interface. The {@link 36 * java.lang.management.ManagementFactory#getPlatformMXBeans getPlatformMXBeans} 37 * method can be used to obtain the list of {@code BufferPoolMXBean} objects 38 * representing the management interfaces for pools of buffers as follows: 39 * <pre> 40 * List<BufferPoolMXBean> pools = ManagementFactory.getPlatformMXBeans(BufferPoolMXBean.class); 41 * </pre> 42 * 43 * <p> The management interfaces are also registered with the platform {@link 44 * javax.management.MBeanServer MBeanServer}. The {@link 45 * javax.management.ObjectName ObjectName} that uniquely identifies the 46 * management interface within the {@code MBeanServer} takes the form: 47 * <pre> 48 * java.nio:type=BufferPool,name=<i>pool name</i> 49 * </pre> 50 * where <em>pool name</em> is the {@link #getName name} of the buffer pool. 51 * 52 * @since 1.7 53 */ 54 public interface BufferPoolMXBean extends PlatformManagedObject { 55 56 /** 57 * Returns the name representing this buffer pool. 58 * 59 * @return The name of this buffer pool. 60 */ getName()61 String getName(); 62 63 /** 64 * Returns an estimate of the number of buffers in the pool. 65 * 66 * @return An estimate of the number of buffers in this pool 67 */ getCount()68 long getCount(); 69 70 /** 71 * Returns an estimate of the total capacity of the buffers in this pool. 72 * A buffer's capacity is the number of elements it contains and the value 73 * returned by this method is an estimate of the total capacity of buffers 74 * in the pool in bytes. 75 * 76 * @return An estimate of the total capacity of the buffers in this pool 77 * in bytes 78 */ getTotalCapacity()79 long getTotalCapacity(); 80 81 /** 82 * Returns an estimate of the memory that the Java virtual machine is using 83 * for this buffer pool. The value returned by this method may differ 84 * from the estimate of the total {@link #getTotalCapacity capacity} of 85 * the buffers in this pool. This difference is explained by alignment, 86 * memory allocator, and other implementation specific reasons. 87 * 88 * @return An estimate of the memory that the Java virtual machine is using 89 * for this buffer pool in bytes, or {@code -1L} if an estimate of 90 * the memory usage is not available 91 */ getMemoryUsed()92 long getMemoryUsed(); 93 } 94