/*

 * Copyright 2007-2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

/* @test

 * @bug 6606598

 * @summary Unit test for java.nio.BufferPoolMXBean

 */

import java.nio.ByteBuffer;

import java.nio.MappedByteBuffer;

import java.nio.BufferPoolMXBean;

import java.nio.channels.FileChannel;

import java.io.File;

import java.io.RandomAccessFile;

import java.lang.management.ManagementFactory;

import javax.management.MBeanServer;

import javax.management.ObjectName;

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;

        }

        // map a file

        File f = File.createTempFile("blah", null);

        f.deleteOnExit();

        RandomAccessFile raf = new RandomAccessFile(f, "rw");

        FileChannel fc = raf.getChannel();

        mbb = fc.map(FileChannel.MapMode.READ_WRITE, 10, 100);

        bufferCount++;

        totalCapacity += mbb.capacity();

        // direct

        List<BufferPoolMXBean> pools =

            ManagementFactory.getPlatformMXBeans(BufferPoolMXBean.class);

        check(pools, bufferCount, totalCapacity);

        // using 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);

    }

}