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 * Copyright (c) 2004, 2010, 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.

 *

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package sun.jvmstat.perfdata.monitor;

import sun.jvmstat.monitor.*;

import java.nio.ByteBuffer;

/**

 * Class for monitoring a PerfData Byte Array instrumentation object.

 *

 * This class is provided to support the PerfStringMonitor classes.

 * Instrumentation objects of this direct type currently cannot be

 * created or monitored.

 *

 * @author Brian Doherty

 * @since 1.5

 * @see sun.jvmstat.instrument.ByteArrayInstrument

 */

public class PerfByteArrayMonitor extends AbstractMonitor

       implements ByteArrayMonitor {

    /**

     * The buffer containing the data for the byte array instrument.

     */

    ByteBuffer bb;

    /**

     * Constructor to create a ByteArrayMonitor for the byte array instrument

     * represented by the data in the given buffer.

     *

     * @param name the name of the instrumentation object

     * @param u the units of measure attribute

     * @param v the variability attribute

     * @param supported support level indicator

     * @param bb the buffer containing the byte array instrument data

     * @param vectorLength the length of the vector.

     */

    public PerfByteArrayMonitor(String name, Units u, Variability v,

                                boolean supported, ByteBuffer bb,

                                int vectorLength) {

        super(name, u, v, supported, vectorLength);

        this.bb = bb;

    }

    /**

     * {@inheritDoc}

     * The object returned contains a byte[] with a copy of the current

     * elements of the ByteArrayInstrument.

     *

     * @return Object - a copy of the current value of the elements of the

     *                  byte array instrument. The return type is guaranteed

     *                  to be of type byte[].

     */

    public Object getValue() {

        return byteArrayValue();

    }

    /**

     * Get a copy of the elements of the byte array instrument.

     *

     * @return byte[] - a copy of the current value of the elements of the

     *                  byte array instrument.

     */

    public byte[] byteArrayValue() {

        bb.position(0);

        byte[] b = new byte[bb.limit()];

        // copy the bytes

        bb.get(b);

        return b;

    }

    /**

     * Get the current value of an element of the byte array instrument.

     *

     * @return byte - a copy of the current value of the element at index

     *                <tt>index</tt> of the byte array instrument.

     */

    public byte byteAt(int index) {

        bb.position(index);

        return bb.get();

    }

    /**

     * Get the maximum length of the byte array for this byte array instrument.

     *

     * @return int - the maximum length of the byte array.

     */

    public int getMaximumLength() {

        return bb.limit();

    }

}