The HL7 listener receives HL7 messages from the message routers located in each health system. The HL7 listener then passes the received HL7 message to the HL7 parser bean, an Enterprise JavaBean (EJB) in the RODS business logic tier. The HL7 parser bean uses regular expressions to parse the fields in an HL7 message. The HL7 parser bean then stores the parsed elements into a database through a managed database connection pool.