/*
* Copyright 2007 Sun Microsystems, Inc.
*
* This file is part of jVoiceBridge.
*
* jVoiceBridge is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation and distributed hereunder
* to you.
*
* jVoiceBridge 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Sun designates this particular file as subject to the "Classpath"
* exception as provided by Sun in the License file that accompanied this
* code.
*/
package com.sun.voip;
import java.lang.reflect.*;
public class CurrentTime {
private CurrentTime() {
}
/*
* Return System.nanoTime() if running java 1.5
* Otherwise return System.currentTimeMillis()
*/
private static Method currentTime = null;
private static Class systemClass = null;
private static int timeUnitsPerSecond = 0;
public static long getTime() {
if (currentTime == null) {
try {
systemClass = Class.forName("java.lang.System");
} catch (Exception e) {
return System.currentTimeMillis(); // something is wrong
}
Method[] methods = systemClass.getMethods();
Method currentTimeMillis = null;
for (int i = 0; i < methods.length; i++) {
Method m = methods[i];
if (m.getName().equals("currentTimeMillis")) {
currentTimeMillis = m;
timeUnitsPerSecond = 1000;
} else if (m.getName().equals("nanoTime")) {
timeUnitsPerSecond = 1000000000;
currentTime = m;
}
}
if (currentTime == null) {
currentTime = currentTimeMillis;
}
if (currentTime == null) {
return System.currentTimeMillis();
}
}
try {
Long now = (Long) currentTime.invoke(systemClass, (Object[]) null);
return now.longValue();
} catch (Exception e) {
return System.currentTimeMillis();
}
}
public static double getElapsedSeconds(long start) {
double elapsed = getTime() - start;
return elapsed / timeUnitsPerSecond;
}
public static int getTimeUnitsPerSecond() {
if (timeUnitsPerSecond == 0) {
getTime();
}
return timeUnitsPerSecond;
}
public static String getTimeUnits() {
long time = CurrentTime.getTime(); // get time units
String s = "milliseconds";
if (timeUnitsPerSecond != 1000) {
s = "nanoseconds";
}
return s;
}
public static void main(String[] args) {
long time = CurrentTime.getTime();
int n = 100000;
if (args.length > 0) {
try {
n = Integer.parseInt(args[0]);
} catch (NumberFormatException e) {
System.out.println(
"invalid count specified. defaulting to " + n);
}
}
long totalTime = 0;
long start = CurrentTime.getTime();
long s = System.currentTimeMillis();
for (int i = 0; i < n; i++) {
long begin = CurrentTime.getTime();
totalTime += (CurrentTime.getTime() - begin);
}
try {
Thread.sleep(20);
} catch (InterruptedException e) {
}
System.out.println("Time units: " + getTimeUnits());
System.out.println("Average time to getTime(): "
+ ((double)totalTime / n / getTimeUnitsPerSecond()));
System.out.println ("elapsed using getTime() "
+ CurrentTime.getElapsedSeconds(start));
System.out.println ("elapsed using currentTimeMillis() "
+ (System.currentTimeMillis() - s));
}
}