Java - Statically defined character lists

Question

In any of the standard libraries is there a definition for characters classes (alpha, numeric, alphanumeric)? I'm checking if a string contains only alphanumeric characters or a colon:

StringUtils.containsOnly(input, ALPHA_NUMERIC + ":");

I could define ALPHA_NUMERIC myself, but it seems common characters classes would be defined in a standard library, although I have been unable to find the definitions.

edit: I did consider regex, but for my particular use case execution time is important, and a simple scan is more efficient.

edit: Here are the test results, using Regex, CharMatcher, and a simple scan (using the same set of valid/invalid input strings for each test):

Valid Input Strings:

CharMatcher, Num Runs: 1000000, Valid Strings: true, Time (ms): 1200

Regex, Num Runs: 1000000, Valid Strings: true, Time (ms): 909

Scan, Num Runs: 1000000, Valid Strings: true, Time (ms): 96

Invalid input strings:

CharMatcher, Num Runs: 1000000, Valid Strings: false, Time (ms): 277

Regex, Num Runs: 1000000, Valid Strings: false, Time (ms): 253

Scan, Num Runs: 1000000, Valid Strings: false, Time (ms): 36

Here is the code that performed the scan:

public boolean matches(String input) {
    for(int i=0; i<input.length(); i++) {
        char c = input.charAt(i);
        if( !Character.isLetterOrDigit(c) && c != ':') {
            return false;
        }
    }
    return true;
}

edit: I recompiled as a standalone program (I was running through eclipse):

CharMatcherTester, Num Runs: 1000000, Valid Strings: true, Time (ms): 418

RegexTester, Num Runs: 1000000, Valid Strings: true, Time (ms): 812

ScanTester, Num Runs: 1000000, Valid Strings: true, Time (ms): 88

CharMatcherTester, Num Runs: 1000000, Valid Strings: false, Time (ms): 142

RegexTester, Num Runs: 1000000, Valid Strings: false, Time (ms): 223

ScanTester, Num Runs: 1000000, Valid Strings: false, Time (ms): 32

Source: https://bitbucket.org/jdeveloperw/testing (This is my first time posting test results to SO, so comments are appreciated.)

Answer 1

Your best bet is probably a regex Pattern.

It should match:

[\p{Alnum}:]*

• \p{Alnum} - ASCII alphanumeric
• [] - character class (any of the characters inside will match one character)
• : - literal :
• * - 0 or more

if it is all alphanumeric (or :).

You can use matches or pre-compile the regex.