counter/perf/PerfStringCounter.java

/*
 * Copyright (c) 2003, 2006, 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.management.counter.perf;

import sun.management.counter.*;
import java.nio.ByteBuffer;
import java.nio.ReadOnlyBufferException;
import java.nio.charset.Charset;

public class PerfStringCounter extends PerfByteArrayCounter
    implements StringCounter {

    private static Charset defaultCharset = Charset.defaultCharset();
    PerfStringCounter(String name, Variability v,
                      int flags, ByteBuffer bb) {
        this(name, v, flags, bb.limit(), bb);
    }

    PerfStringCounter(String name, Variability v, int flags,
                      int maxLength, ByteBuffer bb) {

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

    // override isVector and getVectorLength in ByteArrayCounter
    public boolean isVector() {
        return false;
    }

    public int getVectorLength() {
        return 0;
    }

    public Object getValue() {
        return stringValue();
    }

    public String stringValue() {

        String str = "";
        byte[] b = byteArrayValue();

        if (b == null || b.length <= 1) {
            return str;
        }

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

        // convert byte array to string, using all bytes up to, but
        // not including the first null byte.
        return new String(b , 0, i, defaultCharset);
    }

    /**
     * Serialize as a snapshot object.
     */
    protected Object writeReplace() throws java.io.ObjectStreamException {
        return new StringCounterSnapshot(getName(),
                                         getUnits(),
                                         getVariability(),
                                         getFlags(),
                                         stringValue());
    }

    private static final long serialVersionUID = 6802913433363692452L;
}