Pl/sql to Validate email

Oracle delivers an API in EBS that can validate Email Address Format.However it does not capture the invalidity if Email String were to be say xxx@hostYou may use the below pl/sql function for Email Address Validation.

CREATE OR REPLACE FUNCTION xx_check_email(l_user_name IN VARCHAR2)
RETURN VARCHAR2 IS
l_dot_pos NUMBER;
l_at_pos NUMBER;
l_str_length NUMBER;
BEGIN
l_dot_pos := instr(l_user_name,'.');
l_at_pos := instr(l_user_name,'@');
l_str_length := length(l_user_name);
IF ((l_dot_pos = 0) OR (l_at_pos = 0) OR (l_dot_pos = l_at_pos + 1) OR (l_at_pos = 1) OR (l_at_pos = l_str_length) OR (l_dot_pos = l_str_length)) THEN RETURN 'FAILURE';
END IF;
IF instr(substr(l_user_name,l_at_pos),'.') = 0 THEN RETURN 'FAILURE';
END IF;
RETURN 'SUCCESS';
END xx_check_email;