Question

I am trying to match a character e.g. ‘ if it doesn’t have the character \ before it.

Valid État de l\'impression

Invalid État de l'impression

Valid Saisir l\'utilisateur et le domaine pour la connexion

I believe what I am after is sort of assertion such as a negative lookbehind?

e.g. (?<!\\)' which works fine when I am testing in RegexBuilder

However the problem is when I am trying to make this work in Java

Code

String[] inputs = new String[] { "Recherche d'imprimantes en cours…", "Recherche  d\\'imprimantes en cours…" } ;

for(String input : inputs)
{
    Pattern p = Pattern.compile("(?<!\\\\)'");
    System.out.println(input);
    System.out.println(p.matcher(input).matches());
}

Output

Recherche d'imprimantes en cours…
false
Recherche  d\'imprimantes en cours…
false

Which should match true, false

Answer 1

p.matcher(input).matches() validates the entire input. Try p.matcher(input).find() instead.