public static boolean isUSPhoneMainNumber ( String s ) { if ( isEmpty ( s ) ) return defaultEmptyOK ; String normalizedPhone = stripCharsInBag ( s , phoneNumberDelimiters ) ; return ( isInteger ( normalizedPhone ) && normalizedPhone . length ( ) == digitsInUSPhoneMainNumber ) ; }
isUSPhoneMainNumber returns true if string s is a valid U . S . Phone Main Number . Must be 7 digits .