Character.isWhitespace alternative? (whitespace check)

[Ed]

What is the correct way to check for a white space character?

This is done by the method Character.isWhitespace(char) but not
supported by GWT. What is the alternative?

I know check for whiteSpaces through
someString.charAt(index) == ' ';

But I am not sure if that's good enough as I think I forget things
like \t....

[Dominik Steiner]

did you try to use the regex method

boolean matches = someString.matches("\\S");

HTH

Dominik

[Ed]

Yes I can, but don't want to, as it's way to heave for just checking
if a character is a white space... Especialy in my case where
performance is an issue.

[Dominik Steiner]

Hi Ed,

for performance reason I would definitely recommend you to actually
use regex instead of equals or equalsIgnoreCase methods of the String
class. Especially IE has really performance problems with former ones.
Concerning heavy, I would actually say that it is much cleaner to use
regex and more adaptable in case you would need in the future

HTH

Dominik

[Ed]

Hmmmm Interesting Dominik.
Thanks for the information.
It's sure is clean, but didn't know that performance of regexp is
"good" in this case..

What I want is: if a character at index X is a white space. That means
I always have to take first a substring of one character and then do a
match. So besides checking for a whitespace, I also take a substring,
does that still perform well ??...
Besides that: I always understood that object creation should be
reduces as much as possible. In this case it always creates more
objects...

Might it be a good idea to store the pattern in a static field, to
overcome unnecessary pattern compilation?
So do something like this:

private final static Pattern PATTERN_WHITE_SPACE = Pattern.compile("\
\S");
..
...
..
In a helper method:

public static boolean matchWhiteSpace(String input) {
return PATTERN_WHITE_SPACE.matcher(input).matches();
}

[mars1412]

if performance is really that critical you should test several
alternatives and check which one is really the best for your case (and
don't forget to test cross-browser; especially IE)