/*

 * Copyright (c) 2009, 2013, 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.misc;

import java.nio.ByteBuffer;

import java.nio.ByteOrder;

import java.nio.LongBuffer;

import java.security.AccessController;

/**

 * Performance counter support for internal JRE classes.

 * This class defines a fixed list of counters for the platform

 * to use as an interim solution until RFE# 6209222 is implemented.

 * The perf counters will be created in the jvmstat perf buffer

 * that the HotSpot VM creates. The default size is 32K and thus

 * the number of counters is bounded.  You can alter the size

 * with {@code -XX:PerfDataMemorySize=<bytes>} option. If there is

 * insufficient memory in the jvmstat perf buffer, the C heap memory

 * will be used and thus the application will continue to run if

 * the counters added exceeds the buffer size but the counters

 * will be missing.

 *

 * See HotSpot jvmstat implementation for certain circumstances

 * that the jvmstat perf buffer is not supported.

 *

 */

public class PerfCounter {

    private static final Perf perf =

        AccessController.doPrivileged(new Perf.GetPerfAction());

    // Must match values defined in hotspot/src/share/vm/runtime/perfdata.hpp

    private final String name;

    private final LongBuffer lb;

    private PerfCounter(String name, int type) {

        this.name = name;

        ByteBuffer bb = perf.createLong(name, type, U_None, 0L);

        bb.order(ByteOrder.nativeOrder());

        this.lb = bb.asLongBuffer();

    }

    static PerfCounter newPerfCounter(String name) {

        return new PerfCounter(name, V_Variable);

    }

    static PerfCounter newConstantPerfCounter(String name) {

        PerfCounter c = new PerfCounter(name, V_Constant);

        return c;

    }

    /**

     * Returns the current value of the perf counter.

     */

    public synchronized long get() {

        return lb.get(0);

    }

    /**

     * Sets the value of the perf counter to the given newValue.

     */

    public synchronized void set(long newValue) {

        lb.put(0, newValue);

    }

    /**

     * Adds the given value to the perf counter.

     */

    public synchronized void add(long value) {

        long res = get() + value;

        lb.put(0, res);

    }

    /**

     * Increments the perf counter with 1.

     */

    public void increment() {

        add(1);

    }

    /**

     * Adds the given interval to the perf counter.

     */

    public void addTime(long interval) {

        add(interval);

    }

    /**

     * Adds the elapsed time from the given start time (ns) to the perf counter.

     */

    public void addElapsedTimeFrom(long startTime) {

        add(System.nanoTime() - startTime);

    }

    @Override

    public String toString() {

        return name + " = " + get();

    }

    static class CoreCounters {

        static final PerfCounter pdt   = newPerfCounter("sun.classloader.parentDelegationTime");

        static final PerfCounter lc    = newPerfCounter("sun.classloader.findClasses");

        static final PerfCounter lct   = newPerfCounter("sun.classloader.findClassTime");

        static final PerfCounter rcbt  = newPerfCounter("sun.urlClassLoader.readClassBytesTime");

        static final PerfCounter zfc   = newPerfCounter("sun.zip.zipFiles");

        static final PerfCounter zfot  = newPerfCounter("sun.zip.zipFile.openTime");

    }

    static class WindowsClientCounters {

        static final PerfCounter d3dAvailable = newConstantPerfCounter("sun.java2d.d3d.available");

    }

    /**

     * Number of findClass calls

     */

    public static PerfCounter getFindClasses() {

        return CoreCounters.lc;

    }

    /**

     * Time (ns) spent in finding classes that includes

     * lookup and read class bytes and defineClass

     */

    public static PerfCounter getFindClassTime() {

        return CoreCounters.lct;

    }

    /**

     * Time (ns) spent in finding classes

     */

    public static PerfCounter getReadClassBytesTime() {

        return CoreCounters.rcbt;

    }

    /**

     * Time (ns) spent in the parent delegation to

     * the parent of the defining class loader

     */

    public static PerfCounter getParentDelegationTime() {

        return CoreCounters.pdt;

    }

    /**

     * Number of zip files opened.

     */

    public static PerfCounter getZipFileCount() {

        return CoreCounters.zfc;

    }

    /**

     * Time (ns) spent in opening the zip files that

     * includes building the entries hash table

     */

    public static PerfCounter getZipFileOpenTime() {

        return CoreCounters.zfot;

    }

    /**

     * D3D graphic pipeline available

     */

    public static PerfCounter getD3DAvailable() {

        return WindowsClientCounters.d3dAvailable;

    }

}