/*

 * 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package sun.jvmstat.perfdata.monitor;

import sun.jvmstat.monitor.*;

import java.nio.ByteBuffer;

import java.nio.charset.Charset;

/**

 * Class for monitoring a PerfData String instrument.

 *

 * @author Brian Doherty

 * @since 1.5

 */

public class PerfStringMonitor extends PerfByteArrayMonitor

       implements StringMonitor {

    private static Charset defaultCharset = Charset.defaultCharset();

    /**

     * Constructor to create a StringMonitor object for the string instrument

     * represented by the data in the given buffer.

     *

     * @param name the name of the string instrument

     * @param v the variability attribute

     * @param supported support level indicator

     * @param bb the buffer containing the string instrument data.

     */

    public PerfStringMonitor(String name, Variability v, boolean supported,

                             ByteBuffer bb) {

        this(name, v, supported, bb, bb.limit());

    }

    /**

     * Constructor to create a StringMonitor object for the string instrument

     * represented by the data in the given buffer.

     *

     * @param name the name of the string instrument

     * @param v the variability attribute

     * @param supported support level indicator

     * @param bb the buffer containing the string instrument data.

     * @param maxLength the maximum length of the string data.

     */

    public PerfStringMonitor(String name, Variability v, boolean supported,

                             ByteBuffer bb, int maxLength) {

        super(name, Units.STRING, v, supported, bb, maxLength);

    }

    /**

     * {@inheritDoc}

     * The object returned contains a String with a copy of the current

     * value of the StringInstrument.

     *

     * @return Object - a copy of the current value of the StringInstrument.

     *                  The return value is guaranteed to be of type String.

     */

    public Object getValue() {

        return stringValue();

    }

    /**

     * Return the current value of the StringInstrument as a String.

     *

     * @return String - a copy of the current value of the StringInstrument.

     */

    public String stringValue() {

        String str = "";

        byte[] b = byteArrayValue();

        // catch null strings

        if ((b == null) || (b.length <= 1) || (b[0] == (byte)0)) {

            return str;

        }

        int i;

        for (i = 0; i < b.length && b[i] != (byte)0; i++);

        return new String(b, 0, i, defaultCharset);

    }

}