Sorry... I attached the wrong file. This one actually shows what I am
referring to when I write Test 1, Test 2, Test 3 and Test 4.
On Wed, 2007-01-10 at 16:41 -0500, Tania Bento wrote:
> Hey,
>
> On Tue, 2007-01-09 at 18:01 -0800, David Daney wrote:
> > Roman Kennke wrote:
> > > Hi,
> > >
> > >
> > >> This fixes a minor bug in Permission's toString method. I also changed
> > >> it to use a StringBuffer instead.
> > >>
> > >
> > > Why not use StringBuilder? Seems slightly more efficient.
> > >
> > > /Roman
> > >
> > >
> > Why not leave it much as it was using the string concatenation operator
> > '+'? The compiler converts this to String[Buffer|Builder] when it
> > generates the byte code. IMO this patch makes the code much more
> > difficult to understand with *no* improvement in efficiency.
> >
>
> I've written a quick benchmark that shows the difference between using
> string concatenation, StringBuffer and StringBuilder. The test I used
> is attached. Here are the results (in milliseconds) I got (more or
> less):
>
> Implementation Test 1 Test 2 Test 3 Test 4
> string concatenation 9 120 950 8000
> StringBuffer 8 130 750 7000
> StringBuilder 7 130 740 7500
>
>
> Here is the code for the different implementations I used:
>
> String Concatenation:
>
> String actions = "";
> if (!getActions().equals(""))
> actions = ' ' + getActions() + ' ';
>
> String string = '(' + getClass().getName() + ' '
> + actions + getName() + ')';
>
> return string;
>
> StringBuffer:
>
> String actions = "";
> if (! getActions().equals(""))
> actions = ' ' + getActions() + ' ';
>
> StringBuffer string = new StringBuffer();
> string.append('(').append(getClass().getName()).append(' ').
> append(actions).append(getName()).append(')');
>
> return string.toString();
>
> StringBuilder:
>
> String actions = "";
> if (! getActions().equals(""))
> actions = ' ' + getActions() + ' ';
>
> StringBuilder string = new StringBuilder();
> string.append('(').append(getClass().getName()).append(' ').
> append(actions).append(getName()).append(')');
>
> return string.toString();
>
>
> Let me know your opinions/thoughts on this.
>
> Cheers,
> Tania
>
import java.awt.AWTPermission;
public class Test {
public static void main(String[]args)
{
AWTPermission permission = new AWTPermission("String");
// Test 1
long start = System.currentTimeMillis();
for (int i = 1; i <= 1000; i++)
permission.toString();
long end = System.currentTimeMillis();
long total = end - start;
System.out.println("Calling toString 1000 times: " + total);
// Test 2
start = System.currentTimeMillis();
for (int i = 1; i <= 10000; i++)
permission.toString();
end = System.currentTimeMillis();
total = end - start;
System.out.println("Calling toString 10000 times: " + total);
// Test 3
start = System.currentTimeMillis();
for (int i = 1; i <= 100000; i++)
permission.toString();
end = System.currentTimeMillis();
total = end - start;
System.out.println("Calling toString 100000 times: " + total);
// Test 4
start = System.currentTimeMillis();
for (int i = 1; i <= 1000000; i++)
permission.toString();
end = System.currentTimeMillis();
total = end - start;
System.out.println("Calling toString 1000000 times: " + total);
}
}
