/*

 * Copyright (c) 2004, 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 sun.jvmstat.perfdata.monitor.protocol.local;

import sun.misc.Perf;

import sun.jvmstat.monitor.*;

import sun.jvmstat.perfdata.monitor.*;

import java.util.*;

import java.io.*;

import java.nio.ByteBuffer;

import java.nio.channels.FileChannel;

import java.lang.reflect.Constructor;

import java.security.AccessController;

/**

 * The concrete PerfDataBuffer implementation for the <em>local:</em>

 * protocol for the HotSpot PerfData monitoring implementation.

 * <p>

 * This class is responsible for acquiring access to the shared memory

 * instrumentation buffer for the target HotSpot Java Virtual Machine.

 *

 * @author Brian Doherty

 * @since 1.5

 */

// Suppreess unchecked conversion warning at line 34.

//@SuppressWarnings("unchecked")

public class PerfDataBuffer extends AbstractPerfDataBuffer {

    private static final Perf perf = AccessController.doPrivileged(new Perf.GetPerfAction());

    /**

     * Create a PerfDataBuffer instance for accessing the specified

     * instrumentation buffer.

     *

     * @param vmid the <em>local:</em> URI specifying the target JVM.

     *

     * @throws MonitorException

     */

    public PerfDataBuffer(VmIdentifier vmid) throws MonitorException {

        try {

            // Try 1.4.2 and later first

            ByteBuffer bb = perf.attach(vmid.getLocalVmId(), vmid.getMode());

            createPerfDataBuffer(bb, vmid.getLocalVmId());

        } catch (IllegalArgumentException e) {

            // now try 1.4.1 by attempting to directly map the files.

            try {

                String filename = PerfDataFile.getTempDirectory()

                                  + PerfDataFile.dirNamePrefix

                                  + Integer.toString(vmid.getLocalVmId());

                File f = new File(filename);

                FileChannel fc = new RandomAccessFile(f, "r").getChannel();

                ByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0L,

                                       (int)fc.size());

                fc.close();

                createPerfDataBuffer(bb, vmid.getLocalVmId());

            } catch (FileNotFoundException e2) {

                // re-throw the exception from the 1.4.2 attach method

                throw new MonitorException(vmid.getLocalVmId() + " not found",

                                           e);

            } catch (IOException e2) {

                throw new MonitorException("Could not map 1.4.1 file for "

                                           + vmid.getLocalVmId(), e2);

            }

        } catch (IOException e) {

            throw new MonitorException("Could not attach to "

                                       + vmid.getLocalVmId(), e);

        }

    }

}