CODEWITHSUNDEEP
java
midrigs
midrigs

Reputation: 65

Password requirements program

I am trying to create a program that will take input from user as a password and compare to see if the password meets the requirements. If it doesn't meet requirements, re-prompt user for password again until it meets the requirements. Here is what I have and I don't understand why it doesn't work...

import javax.swing.*;

public class Password {

public static void main(String[] args) {
    //
    String pInput = "";

    do {
        pInput = JOptionPane.showInputDialog(null, "Please enter your password.\n"
                                                    + "Your password must have 6-10 characters\n"
                                                    + "Your password must contain at least one letter and one digit");
    }
    while (authenticate(pInput) == false);

    JOptionPane.showMessageDialog(null, "Your password was successfully entered.");
}   

private static boolean authenticate(String password)
{
    // The password should be at least six characters long.
    // The password should contain at least one letter.
    // The password should have at least one digit.
     if ((password.length() > 6) &&
        (password.length() < 10) &&
        (password.matches("[a-z]")) &&
        (password.matches("[0-9]")))
         return true;
     else
         return false;
    }
}

Upvotes: 2

Views: 4445

Answers (5)

kamlesh
kamlesh

Reputation: 154

I think problem is in function's if block, use following code

if ((password.length() >= 6) &&
        (password.length() <= 10) &&
        (password.matches(".*[a-z]+.*")) &&
        (password.matches(".*[0-9]+.*")))
         return true;

Upvotes: 0

Elliott Frisch
Elliott Frisch

Reputation: 201447

If I understand your question, I would rename your authenticate() method (it's really validate()),

// validate that a password adheres to the "rules".
private static boolean validate(String password) {
  // Check for null, then a length less then 6 (and I really don't like the length()
  // > 10 check, that's a BAD requirement).
  if (password == null || password.length() < 6 || password.length() > 10) {
    return false;
  }
  boolean containsChar = false;
  boolean containsDigit = false;
  for (char c : password.toCharArray()) {
    if (Character.isLetter(c)) {
      containsChar = true;
    } else if (Character.isDigit(c)) {
      containsDigit = true;
    }
    if (containsChar && containsDigit) {
      return true;
    }
  }
  return false;
}

Personally, I would prefer to avoid a regex because they are often confusing. If it's a requirement, then the one added as a comment to the question by @MadProgrammer might be used,

private static final Pattern pattern = Pattern
    .compile("^(?=.*\\d)(?=.*[a-zA-Z]).{6,10}$"); // <-- note "\\d"

private static boolean validate(String password) {
  return pattern.matcher(password).matches();
}

Upvotes: 3

Nir Alfasi
Nir Alfasi

Reputation: 53535

Change the regex in the authentication method:

private static boolean authenticate(String password)
{
    // The password should be at least six characters long.
    // The password should contain at least one letter.
    // The password should have at least one digit.
    if ((password.length() >= 6) &&
            (password.length() <= 10) &&
            (password.matches("^(?:.*[a-z].*)(?:.*[0-9].*)$")))
        return true;
    else
        return false;
}

Using non-capturing lookahead patterns will enable the validation you want. The original version did not work because it was trying to match the password to: "[a-z]" and "[0-9]" simultaneously - a condition that will always return false!

Upvotes: 1

zelda
zelda

Reputation: 33

you should change :

  • password.length() >6 into password.length() >= 6

  • password.length() <10 into password.length() <=10

    because you want at least six characters long. and most ten characters long.

  • password.matches("[a-z]") into password.matches(".[a-z]+.") because .matches("[a-z]") is used for check a character not for string

this one is edited version

private static boolean authenticate(String password)
{
    // The password should be at least six characters long.
    // The password should contain at least one letter.
    // The password should have at least one digit.
     if ((password.length() >= 6) &&
        (password.length() <= 10)&&
        (password.matches(".*[a-z]+.*")) &&
        (password.matches(".*[0-9]+.*")) )
         return true;
     else
         return false;
    }
}

Upvotes: 2

ethanfar
ethanfar

Reputation: 3778

You need to change:

  • password.length() > 6 into: password.length() >= 6
  • password.length() < 10 into: password.length() <= 10
  • (password.matches("[a-z]")) && (password.matches("[0-9]")) into: password.matches(".*[a-z]+.*") && password.matches(".*[0-9]+.*")

The first two are because you want the 6-10 range to be inclusive (so it sounds from your requirements).
The third change is because you need the regular pattern to match the entire password, not just a single character.

Upvotes: 0

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