public class ValidatePhoneNumberUsingLocalClass {
  
  static String regularExpression = "[^0-9]";
  
  public static void validatePhoneNumber(String number) {
    
    final int numberLength = 10;
     
    class PhoneNumber {
      
      private String formattedPhoneNumber = null;

      PhoneNumber(String phoneNumber){        
        regularExpression = "[^0-9]";
        String currentNumber = phoneNumber.replaceAll(
          regularExpression, "");
        if (currentNumber.length() == numberLength)
          formattedPhoneNumber = currentNumber;
        else
          formattedPhoneNumber = null;
      }

      public String getNumber() {
        return formattedPhoneNumber;
      }
      
      public String toString() {
        if(formattedPhoneNumber == null)
          return "Invalid number\n";
        else
          return formattedPhoneNumber;
      }
      
      //    public void printOriginalNumbers() {
      //      System.out.println("Original numbers are " + phoneNumber1 +
      //          " and " + phoneNumber2);
      //    }
    }

    //  myNumber1.printOriginalNumbers();
    System.out.println(number + ": " + new PhoneNumber(number));
  }

  public static void main(String... args) {
    ValidatePhoneNumberUsingLocalClass.validatePhoneNumber("123-456-7890");
    ValidatePhoneNumberUsingLocalClass.validatePhoneNumber("456-7890");
  }
}