How to emulate SOQL LIKE matching in Apex?

Question

I have a need to replicate SOQL's LIKE behaviour in Apex:

• The % wildcard matches zero or more characters
• The _ wildcard matches exactly one character
• Case insensitive

including for cases where characters that have special meaning in regular expressions are used e.g. ( and ). What code do I need?

Answer 1

Couldn't find code for this anywhere - many examples ignore the possibility of characters that have special meaning in regular expressions being present.

This is what I ended up with as a solution, posted here in case it helps anyone else (and in case there is a better way to do it).

Updated per Derek F's feedback:

public static Boolean soqlLikeMatch(String candidate, String soqlLike) {

    // Escape regex special characters but keep the % and _ and space characters,
    // \w matches alphanumeric characters,
    // four backslashes translate to one escaped backslash i.e. \\
    String regex = soqlLike.replaceAll('([^\\w%_ ])', '\\\\$1');

    // Make case insensitive,
    // lock down start/end match,
    // convert SOQL wildcards to regex ones
    regex = '(?i)' + '^' + regex.replace('%', '.*?').replace('_', '.{1}?') + '$';

    return Pattern.matches(regex, candidate);
}

Answer 2

If you're looking for a solution to compare, then this could help :

String mainString='main string ';
String searchString='str';
Boolean check=mainString.toLowerCase().indexOf(searchString.toLowerCase())>0);