http://www.regular-expressions.info/lookaround.html
E.g. to remove all @Component annotations from non-"Default" classes:
search for (negative lookahead):
@Component\npublic class (?!Default)
replace with:
public class
negative lookahead: q(?!u) matches a "q" not followed by a "u"
positive lookahead: q(?=u) matches a q that is followed by a u, without making the u part of the match
If you want to store the match of the regex inside a backreference, you have to put capturing parentheses around the regex inside the lookahead, like this:(?=(regex)).
negative lookbehind: (?<!a)b matches a "b" that is not preceded by an "a", using negative lookbehind.
positive lookbehind: (?<=a)b matches the b (and only the b) in cab
