public static boolean isUSPhoneAreaCode ( String s ) { if ( isEmpty ( s ) ) return defaultEmptyOK ; String normalizedPhone = stripCharsInBag ( s , phoneNumberDelimiters ) ; return ( isInteger ( normalizedPhone ) && normalizedPhone . length ( ) == digitsInUSPhoneAreaCode ) ; }
isUSPhoneAreaCode returns true if string s is a valid U . S . Phone Area Code . Must be 3 digits .