On Fri, 2003-03-14 at 19:00, Alex Chaffee / Purple Technology wrote:
> On Fri, Mar 14, 2003 at 12:34:56PM +0000, Henning P. Schmiedehausen wrote:
> > Henri Yandell <[EMAIL PROTECTED]> writes:
> >
> > >Is there any reason why split/join are special?
> >
> > I need them. :-) And splitting at a single char / joining with a
> > single char as delimiter is needed very often and using '.' is more
> > efficient than "."
>
> I believe you, but I prefer clean interfaces to performance
> optimizations. If you run a quick performance test -- compare
> splitting and joining, say, a 10-item and a 10000-item list both by
> char and by String -- and post the results (or add them to the bug
> report) it might help make your case.
Without my patch:
What 10 items 10.000 item 100.000 item
Iterations 10000 100 100
join(Object[], String sep) 91 millis 478 millis 13939 millis
join(Iterator, String sep) 87 millis 977 millis 27737 millis
join(Object[], null) 44 millis 518 millis 13628 millis
join(Iterator, null) 74 millis 935 millis 22989 millis
With my patch:
What 10 items 10.000 item 100.000 item
Iterations 10000 100 100
join(Object[], String sep) 92 millis 480 millis 13801 millis
join(Iterator, String sep) 87 millis 981 millis 27774 millis
join(Object[], char sep) 40 millis 387 millis 13070 millis
join(Iterator, char sep) 71 millis 931 millis 27114 millis
join(Object[], null) 33 millis 337 millis 12498 millis
join(Iterator, null) 61 millis 800 millis 21756 millis
So the "char" operations are quite a bit faster especially with short array
lengths. The join operation with null separator has been speeded up quite a
bit (and concatenate() does map now on this).
So please, apply the patch. :-)
Test suite attached.
Regards
Henning
--
Dipl.-Inf. (Univ.) Henning P. Schmiedehausen INTERMETA GmbH
[EMAIL PROTECTED] +49 9131 50 654 0 http://www.intermeta.de/
Java, perl, Solaris, Linux, xSP Consulting, Web Services
freelance consultant -- Jakarta Turbine Development -- hero for hire
import java.util.ArrayList;
import java.util.Iterator;
import org.apache.commons.lang.StringUtils;
public class SpeedTest
{
public static void main(String [] args)
{
if (args.length < 2)
System.exit(1);
SpeedTest st = new SpeedTest(args[0], args[1]);
st.run();
}
private int splitsize = 0;
private int loops = 0;
private long startTime, endTime;
private String [] foo;
private ArrayList al;
public SpeedTest(String splitSize, String loops)
{
this.splitsize = Integer.parseInt(splitSize);
this.loops = Integer.parseInt(loops);
}
public void run()
{
System.out.println("Starting up...");
foo = new String[splitsize];
al = new ArrayList();
for (int i = 0 ; i < splitsize; i++)
{
foo[i] = "demostring";
al.add("demostring");
}
runObjStr();
System.gc();
runIterStr();
System.gc();
runObjChar();
System.gc();
runIterChar();
System.gc();
runObj();
System.gc();
runIter();
}
private void runObjStr()
{
System.out.println("Running " + loops + " iterations of join(Object[], String separator)");
startTime = System.currentTimeMillis();
for (int i = 0 ; i < loops; i++)
{
String newString = null;
newString = StringUtils.join(foo, ".");
}
endTime = System.currentTimeMillis();
System.out.println("Took " + (endTime - startTime) + " Millisec.");
}
private void runIterStr()
{
System.out.println("Running " + loops + " iterations of join(Iterator, String separator)");
startTime = System.currentTimeMillis();
for (int i = 0 ; i < loops; i++)
{
String newString = null;
newString = StringUtils.join(al.iterator(), ".");
}
endTime = System.currentTimeMillis();
System.out.println("Took " + (endTime - startTime) + " Millisec.");
}
private void runObj()
{
System.out.println("Running " + loops + " iterations of join(Object[], null)");
startTime = System.currentTimeMillis();
for (int i = 0 ; i < loops; i++)
{
String newString = null;
newString = StringUtils.join(foo, null);
}
endTime = System.currentTimeMillis();
System.out.println("Took " + (endTime - startTime) + " Millisec.");
}
private void runIter()
{
System.out.println("Running " + loops + " iterations of join(Iterator, null)");
startTime = System.currentTimeMillis();
for (int i = 0 ; i < loops; i++)
{
String newString = null;
newString = StringUtils.join(al.iterator(), null);
}
endTime = System.currentTimeMillis();
System.out.println("Took " + (endTime - startTime) + " Millisec.");
}
private void runObjChar()
{
System.out.println("Running " + loops + " iterations of join(Object[], char separator)");
startTime = System.currentTimeMillis();
for (int i = 0 ; i < loops; i++)
{
String newString = null;
newString = StringUtils.join(foo, '.');
}
endTime = System.currentTimeMillis();
System.out.println("Took " + (endTime - startTime) + " Millisec.");
}
private void runIterChar()
{
System.out.println("Running " + loops + " iterations of join(Iterator, char separator)");
startTime = System.currentTimeMillis();
for (int i = 0 ; i < loops; i++)
{
String newString = null;
newString = StringUtils.join(al.iterator(), '.');
}
endTime = System.currentTimeMillis();
System.out.println("Took " + (endTime - startTime) + " Millisec.");
}
}
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