Java Regular Expression - allow only certain characters and digits

Question

I need to write regular expression that allows only digits, characters like & | . ( ) and spaces.

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
    public static void main (String[] args) throws java.lang.Exception
    {

        List<String> input = new ArrayList<String>();
        input.add("(0.4545 && 0.567) || 456"); // should PASS
        input.add("9876-5-4321");
        input.add("987-65-4321 (attack)");
        input.add("(0.4545 && 0.567) || 456 && (me)");
        input.add("0.456 && 0.567"); // should PASS
        for (String ssn : input) {
            boolean f = ssn.matches("^[\\d\\s()&|.]$");
            if (f) {
                System.out.println("Found good SSN: " + ssn);
            }else {
                System.out.println("Nope: " + ssn);
            }
        }
    }
}

None above passed, why?

Answer 1

You forgot to add + after character class. Without it your regex will only accept one-character strings with characters from your character class. Try with

boolean f = ssn.matches("^[\\d\\s()&|.]+$");

Answer 2

Because your regular expression accepts single input only (either digits or characters or symbols you specified)

Use ^[\\\\d\\\\s()&|.]*$ for getting multiple times

'+ 1 or more'

? 0 or one

'* 0 or more'