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	/*
	* 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
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	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 -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 static int V_Constant = 1;
	private final static int V_Monotonic = 2;
	private final static int V_Variable = 3;
	private final static int U_None = 1;

	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;
	}
	}

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