public class RegexTester {
	
	public static void main ( String [ ] args ) {
		
		if ( args.length < 2 ) {
			usage();
			System.exit(2);
		}
		
		String email = args[ 0 ];
		String password = args[ 1 ];
		
		try {
			checkEmailAddress( email );
			checkPassword( password );
			System.out.println( "Email and password OK." );
		}
		catch ( Exception e ) {
			System.err.println( e.getMessage() );
			System.exit(1);
		}
		
		System.exit(0);
		
	}	
	
	public static void checkEmailAddress ( String email )
						throws Exception {
		
		if ( !email.matches("^[_a-z0-9-]+(\\.[_a-z0-9-]+)*@[a-z0-9-]+" +
								"(\\.[a-z0-9-]+)*(\\.[a-z]{2,4})$") ) {
			throw new Exception( "Error, invalid email address" );
		}
		
	}
	
	public static void checkPassword ( String password )
						throws Exception {
		
		if ( !password.matches("^\\w*(?=\\w*\\d)(?=\\w*[a-z])(?=\\w*[A-Z])\\w*$") ||
				password.length() < 8 ) {
			throw new Exception( "Error, bad password or password not complex enough." );
		}
		
	}	
	
	public static void usage ( ) {
		System.err.println( "Usage: java RegexTester username password" );
	}	

} /* RegexTester */