HL7DFDLOutput node

The HL7DFDLOutput node receives an HL7 message in the DFDL domain and opens connections to a destination application that is listening on a TCP/IP port. When the connection is established, the HL7 message is sent with an end of record that is set to the Trailing MLLP bytes property delimiter, which has a default value of 1C0D. If the data was not sent successfully within the time limit that is specified by the Timeout sending data record (seconds) property for the node, the message is passed to the Failure terminal.

After successfully sending the message, the HL7DFDLOutput node waits for an acknowledgment (ACK) from the destination application. An HL7 acknowledgment is stripped of MLLP bytes, parsed, and the return code is checked. If an error occurs in the HL7DFDLOutput node, the message is passed either to the Log Retry terminal or the Failure terminal.

If delivery succeeds and an AR code is returned in the acknowledgment, and if the retry limit was not exceeded, the message is passed to the Log Retry terminal.

If the message is delivered and an AE code is returned in the acknowledgment, or if no valid acknowledgment is received, the message is passed to the Failure terminal.

If the message is not delivered it is assumed that the destination is not available and, if the retry limit was not exceeded, the message is passed to the Log Retry terminal.

If the Log Retry terminal is not connected, or if the path ends in success, delivery is tried again. If the Log Retry terminal is connected and an exception is thrown downstream, there is no attempt to try sending the message again and the message is passed to the Failure terminal.

If the Failure terminal is not connected, an exception is thrown.

For information about HL7, see Health Level Seven International.

The HL7DFDLOutputnode is contained in the Healthcare drawer of the message flow node palette, and is represented in the IBM® Integration Toolkit by the following icon:

An example of how to use the HL7DFDLOutput node is shown in the Healthcare: HL7 to HL7 built-in pattern in the Healthcare category in the Patterns Explorer view.

When a HL7DFDLOutput node is used in a message flow, the node expects to find a message in the DFDL tree that has been parsed against the HL7 message in the DFDL message model. If you are not certain that messages passed to the HL7DFDLOutput node are correct, you can set the Validate property to force parsing before processing begins. If the message is successfully sent to the configured destination and an acknowledgment of successful processing is returned from the destination, the acknowledgment is passed to the Out terminal of the node.

If you want the node to try sending the message again after a failure, you must set the value of the Retry limit property to the number of times that you want the node to try to send the message. The node tries again every 10 seconds, but you can alter the interval by changing the Retry interval (seconds) property. If you also want to log every attempt, you must select the Log retry property. When the Log retry property is selected, the message is passed to the Log Retry terminal for each attempt. The Environment holds the values that you can use in your log message, see the following Environment table.

If you wire the Log Retry terminal, the message flow thread ends in success and there are further attempts to send the message. If uncaught exceptions are thrown on this thread, the retries do not continue.

If a message is passed to the Failure terminal, your message flow acts according to your error handling procedures. The Failure terminal must be connected so that the error is logged and the data is either saved, an exception is thrown, or both. If the Failure terminal is not connected, the error causes silent failure, no exception is thrown, and no events are recorded in the event log. For error codes and other information that you can use in your error handling, see the following Error table.

If a failure occurs in the HL7DFDLOutput node, the message is passed to the Failure terminal. LocalEnvironment.HL7 contains the fields that are shown in the following Environment table. These fields give information that is used to build a negative acknowledgment (NACK) or create an error message.

The following Error table indicates the error codes that can occur.

After you add an instance of a HL7DFDLOutput node into a message flow, you can configure it

All mandatory properties for which you must enter a value (properties that do not have a default value defined) are marked with an asterisk.

The following tables describe the node properties. The column headed M indicates whether the property is mandatory (marked with an asterisk if you must enter a value when no default is defined); the column headed C indicates whether the property is configurable (you can change the value when you add the message flow to the broker archive (BAR) file to deploy it).

The Basic properties for the HL7DFDLOutput node are described in the following table.

Property	M	C	Default	Description
Connection details	Yes	Yes	localhost:2222	The TCP/IP connection for the destination application in the form hostname:port
Timeout sending data record (seconds)	Yes	Yes	60	The time in seconds that the node waits when you attempt to send data or to receive an acknowledgment.
Leading MLLP byte	Yes	Yes	0B	The leading MLLP byte, which is added to outgoing HL7 records and removed from incoming acknowledgments.
Retry limit	Yes	Yes	5	The maximum number of times the node attempts to deliver an HL7 message to the destination application.
Retry interval (seconds)	Yes	Yes	10	The interval, in seconds, between each attempt to deliver an HL7 message to the destination application.
Log retry	No	Yes	Selected	Specifies whether each attempt to deliver a message is passed to the Log Retry terminal to allow logging.