/*
* Copyright (c) 2007, 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
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.lang.management;
/**
* The management interface for a buffer pool, for example a pool of
* {@link java.nio.ByteBuffer#allocateDirect direct} or {@link
* java.nio.MappedByteBuffer mapped} buffers.
*
* <p> A class implementing this interface is an
* {@link javax.management.MXBean}. A Java
* virtual machine has one or more implementations of this interface. The {@link
* java.lang.management.ManagementFactory#getPlatformMXBeans getPlatformMXBeans}
* method can be used to obtain the list of {@code BufferPoolMXBean} objects
* representing the management interfaces for pools of buffers as follows:
* <pre>
* List<BufferPoolMXBean> pools = ManagementFactory.getPlatformMXBeans(BufferPoolMXBean.class);
* </pre>
*
* <p> The management interfaces are also registered with the platform {@link
* javax.management.MBeanServer MBeanServer}. The {@link
* javax.management.ObjectName ObjectName} that uniquely identifies the
* management interface within the {@code MBeanServer} takes the form:
* <pre>
* java.nio:type=BufferPool,name=<i>pool name</i>
* </pre>
* where <em>pool name</em> is the {@link #getName name} of the buffer pool.
*
* @since 1.7
*/
public interface BufferPoolMXBean extends PlatformManagedObject {
/**
* Returns the name representing this buffer pool.
*
* @return The name of this buffer pool.
*/
String getName();
/**
* Returns an estimate of the number of buffers in the pool.
*
* @return An estimate of the number of buffers in this pool
*/
long getCount();
/**
* Returns an estimate of the total capacity of the buffers in this pool.
* A buffer's capacity is the number of elements it contains and the value
* returned by this method is an estimate of the total capacity of buffers
* in the pool in bytes.
*
* @return An estimate of the total capacity of the buffers in this pool
* in bytes
*/
long getTotalCapacity();
/**
* Returns an estimate of the memory that the Java virtual machine is using
* for this buffer pool. The value returned by this method may differ
* from the estimate of the total {@link #getTotalCapacity capacity} of
* the buffers in this pool. This difference is explained by alignment,
* memory allocator, and other implementation specific reasons.
*
* @return An estimate of the memory that the Java virtual machine is using
* for this buffer pool in bytes, or {@code -1L} if an estimate of
* the memory usage is not available
*/
long getMemoryUsed();
}