/**
* Helios, OpenSource Monitoring
* Brought to you by the Helios Development Group
*
* Copyright 2007, Helios Development Group and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*
*/
package org.helios.apmrouter.util;
import org.helios.apmrouter.collections.ILongStack;
import org.helios.apmrouter.collections.UnsafeLongStack;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;
/**
* <p>Title: NestedSystemClock</p>
* <p>Description: SystemClock timing collector that supports nested calls and detects skipped pops.</p>
* <p>Company: Helios Development Group LLC</p>
* @author Whitehead (nwhitehead AT heliosdev DOT org)
* <p><code>org.helios.apmrouter.util.NestedSystemClock</code></p>
*/
public class NestedSystemClock {
/** Holds the start timestamp of an elapsed time measurement */
private static final ThreadLocal<ILongStack> timerStart = new ThreadLocal<ILongStack>() {
@Override
protected ILongStack initialValue() {
return new UnsafeLongStack();
}
@Override
public void remove() {
ILongStack stack = this.get();
if(stack!=null) stack.destroy();
super.remove();
};
};
/**
* Starts a timer, returning the key that should be passed to retrieve the elapsed time
* for this specific start instance.
* @return the elapsed time retrieval key
*/
public static int startTimer() {
final ILongStack stack = timerStart.get();
stack.push(SystemClock.time());
return stack.size();
}
/**
* Ends the current timer and returns an ElapedTime instance
* @param key The clock key provided when this timer was started
* @return an ElapsedTime instance
*/
public static ElapsedTime endTimer(int key) {
if(key<1) throw new IllegalArgumentException("The passed value [" + key + "] is an invalid clock key", new Throwable());
final long currentTime = SystemClock.time();
final ILongStack stack = timerStart.get();
final int currentSize = stack.size();
if(currentSize!=key) {
if(key>currentSize) {
timerStart.remove();
throw new IllegalStateException("Provided key [" + key + "] was greater than the size of the timestamp stack [" + currentSize + "]. Stack has been destroyed.", new Throwable());
}
while(stack.size() > key) {
stack.pop();
}
}
final long startTime = stack.pop();
if(stack.size()<1) timerStart.remove();
return new ElapsedTime(startTime, currentTime);
}
/**
* Returns the elapsed lap time based off the top start time in the start time stack
* @return a lap ElapsedTime instance
*/
public static ElapsedTime lapTimer() {
final long currentTime = SystemClock.time();
final ILongStack stack = timerStart.get();
final int currentSize = stack.size();
if(currentSize<1) {
throw new IllegalStateException("lapTimer called, but there is no start time in the stack.", new Throwable());
}
return new ElapsedTime(stack.peek(), currentTime);
}
/**
* Returns an elapsed lap time based on the indexed start time.
* Note that this is not the same value as the time key since it references the stack directly.
* To use a provided key, subtract 1 from that value.
* @param index The index to get the start time with
* @return a lap ElapsedTime instance
*/
public static ElapsedTime lapTimer(int index) {
final long currentTime = SystemClock.time();
final ILongStack stack = timerStart.get();
final int currentSize = stack.size();
if(index>currentSize) {
throw new IllegalStateException("Invalid lap time request. Provided index [" + index + "] was greater than the size of the timestamp stack [" + currentSize + "].", new Throwable());
}
return new ElapsedTime(stack.get(index), currentTime);
}
/**
* Returns the size of the elapsed time sack
* @return the size of the elapsed time sack
*/
public static int getCurrentStackSize() {
final ILongStack stack = timerStart.get();
if(stack.size()==0) {
timerStart.remove();
return 0;
}
return stack.size();
}
/**
* <p>Title: ElapsedTime</p>
* <p>Description: Encapsulates various values associated to a timer's elapsed time.</p>
*/
public static class ElapsedTime {
/** The start timestamp in ns. */
public final long startNs;
/** The end timestamp in ns. */
public final long endNs;
/** The elapsed time in ns. */
public final long elapsedNs;
/** The elapsed time in ms. */
public final long elapsedMs;
/** Some extended time unit entries */
public static final Map<TimeUnit, String> UNITS;
static {
Map<TimeUnit, String> tmp = new HashMap<TimeUnit, String>();
tmp.put(TimeUnit.DAYS, "days");
tmp.put(TimeUnit.HOURS, "hrs.");
tmp.put(TimeUnit.MICROSECONDS, "us.");
tmp.put(TimeUnit.MILLISECONDS, "ms.");
tmp.put(TimeUnit.MINUTES, "min.");
tmp.put(TimeUnit.NANOSECONDS, "ns.");
tmp.put(TimeUnit.SECONDS, "s.");
UNITS = Collections.unmodifiableMap(tmp);
}
private ElapsedTime(long startTime, long endTime) {
endNs = endTime;
startNs = startTime;
elapsedNs = endNs - startNs;
elapsedMs = TimeUnit.MILLISECONDS.convert(elapsedNs, TimeUnit.NANOSECONDS);
}
/**
* Returns the average elapsed time in ms. for the passed number of events
* @param cnt The number of events
* @return The average elapsed time in ms.
*/
public long avgMs(double cnt) {
return _avg(elapsedMs, cnt);
}
/**
* Returns the average elapsed time in ns. for the passed number of events
* @param cnt The number of events
* @return The average elapsed time in ns.
*/
public long avgNs(double cnt) {
return _avg(elapsedNs, cnt);
}
private long _avg(double time, double cnt) {
if(time==0 || cnt==0 ) return 0L;
double d = time/cnt;
return Math.round(d);
}
public String toString() {
StringBuilder b = new StringBuilder("[");
b.append(elapsedNs).append("] ns.");
b.append(" / [").append(elapsedMs).append("] ms.");
return b.toString();
}
public long elapsed() {
return elapsed(TimeUnit.NANOSECONDS);
}
public long elapsed(TimeUnit unit) {
if(unit==null) unit = TimeUnit.NANOSECONDS;
return unit.convert(elapsedNs, TimeUnit.NANOSECONDS);
}
public String elapsedStr(TimeUnit unit) {
if(unit==null) unit = TimeUnit.NANOSECONDS;
return new StringBuilder("[").append(unit.convert(elapsedNs, TimeUnit.NANOSECONDS)).append("] ").append(UNITS.get(unit)).toString();
}
public String elapsedStr() {
return elapsedStr(TimeUnit.NANOSECONDS);
}
}
}