Regex : Digits followed by only one character

Question

I'm trying to create a regex that will allow only digits followed by only one character after every digit within a Textfield

Regex that needs to match - \\d*\\+{1}

Regex in case it does not match - [^\\d*\\+){1}] will replace with "" (removes everything else)

final String regexFinalInteger = "\\d*\\+{1}";

    numberElements.textProperty().addListener((observable, oldValueE, newValueE) -> {
        if (!newValueE.matches(regexFinalInteger)) {
            numberElements.setText(newValueE.replaceAll("[^\\d*\\+){1}]", ""));
        }
    });

I will expect an output of 122+1+3 but the actual output can be 1++2+++4+123 (multiple +)

Answer 1

If I understood correctly, you want to replace multiple + s with only one.

I believe this would enable what you're looking for:

String regex = "[+](?=[+])";

String text = "122+1+3";
assertEquals("122+1+3", text.replaceAll(regex, ""));

text = "1++2+++4+123";
assertEquals("1+2+4+123", text.replaceAll(regex, ""));

That is my first Java program, I'm sorry if it offends someone.