| /* |
| * Copyright (c) 2007, 2016, 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. |
| * |
| * 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. |
| */ |
| |
| /* @test |
| * @bug 6606598 7024172 |
| * @summary Unit test for java.lang.management.BufferPoolMXBean |
| * @modules jdk.management |
| * @run main/othervm Basic |
| * @key randomness |
| */ |
| |
| import java.nio.ByteBuffer; |
| import java.nio.MappedByteBuffer; |
| import java.nio.file.Path; |
| import java.nio.file.Files; |
| import static java.nio.file.StandardOpenOption.*; |
| import java.nio.channels.FileChannel; |
| import java.lang.management.BufferPoolMXBean; |
| import java.lang.management.ManagementFactory; |
| import javax.management.MBeanServer; |
| import javax.management.ObjectName; |
| import java.lang.ref.WeakReference; |
| import java.util.*; |
| |
| public class Basic { |
| |
| // static fields to ensure buffers aren't GC'ed |
| static List<ByteBuffer> buffers; |
| static MappedByteBuffer mbb; |
| |
| // check counters |
| static void check(List<BufferPoolMXBean> pools, |
| int minBufferCount, |
| long minTotalCapacity) |
| { |
| int bufferCount = 0; |
| long totalCap = 0; |
| long totalMem = 0; |
| for (BufferPoolMXBean pool: pools) { |
| bufferCount += pool.getCount(); |
| totalCap += pool.getTotalCapacity(); |
| totalMem += pool.getMemoryUsed(); |
| } |
| if (bufferCount < minBufferCount) |
| throw new RuntimeException("Count less than expected"); |
| if (totalMem < minTotalCapacity) |
| throw new RuntimeException("Memory usage less than expected"); |
| if (totalCap < minTotalCapacity) |
| throw new RuntimeException("Total capacity less than expected"); |
| } |
| |
| public static void main(String[] args) throws Exception { |
| Random rand = new Random(); |
| |
| // allocate a few direct buffers |
| int bufferCount = 5 + rand.nextInt(20); |
| buffers = new ArrayList<ByteBuffer>(bufferCount); |
| long totalCapacity = 0L; |
| for (int i=0; i<bufferCount; i++) { |
| int cap = 1024 + rand.nextInt(4096); |
| buffers.add( ByteBuffer.allocateDirect(cap) ); |
| totalCapacity += cap; |
| } |
| |
| // create a mapped buffer |
| Path tmpfile = Files.createTempFile("blah", null); |
| tmpfile.toFile().deleteOnExit(); |
| try (FileChannel fc = FileChannel.open(tmpfile, READ, WRITE)) { |
| mbb = fc.map(FileChannel.MapMode.READ_WRITE, 10, 100); |
| bufferCount++; |
| totalCapacity += mbb.capacity(); |
| } |
| |
| // use platform MXBeans directly |
| List<BufferPoolMXBean> pools = |
| ManagementFactory.getPlatformMXBeans(BufferPoolMXBean.class); |
| check(pools, bufferCount, totalCapacity); |
| |
| // use MBeanServer |
| MBeanServer server = ManagementFactory.getPlatformMBeanServer(); |
| Set<ObjectName> mbeans = server.queryNames( |
| new ObjectName("java.nio:type=BufferPool,*"), null); |
| pools = new ArrayList<BufferPoolMXBean>(); |
| for (ObjectName name: mbeans) { |
| BufferPoolMXBean pool = ManagementFactory |
| .newPlatformMXBeanProxy(server, name.toString(), BufferPoolMXBean.class); |
| pools.add(pool); |
| } |
| check(pools, bufferCount, totalCapacity); |
| |
| // attempt to unmap mapped buffer |
| WeakReference<MappedByteBuffer> ref = new WeakReference<>(mbb); |
| mbb = null; |
| do { |
| System.gc(); |
| Thread.sleep(250); |
| } while (ref.get() != null); |
| } |
| } |