The HL7 Transport ( New in Carbon 4.0 ) is available as an installable feature in WSO2 products. The user can simply plug it in if necessity, through the installation of the relevant feature. For instructions to install HL7 transport and adding a proxy service, refer to
The HL7 transport configuration is as follows
<transportConfig> <transportReceiver name="hl7" class="org.wso2.carbon.business.messaging.hl7.transport.HL7TransportListener"> <parameter name="port">9292</parameter> </transportReceiver> <transportSender name="hl7" class="org.wso2.carbon.business.messaging.hl7.transport.HL7TransportSender"> <!--parameter name="non-blocking">true</parameter--> </transportSender> </transportConfig>
The "Axis2 Transport HL7" feature supports the following improvements from version 4.0.0 onwards.
HL7 Conformance Profile Support
The service-level parameter "transport.hl7.ConformanceProfilePath" points to a URL where the conformance profile XML can be found.
HL7 Message Pre-Processing
An implementation of the interface "org.wso2.carbon.business.messaging.hl7.common.HL7MessagePreprocessor" can be used to process raw HL7 messages before parsing them, so that potential errors in the messages can be rectified using it. The service-level parameter used to mention the implementation class is "transport.hl7.MessagePreprocessorClass".
Capability to Enable/Disable Automatic ACK/NACK at Suitable Times
Supports disabling or enabling automatic message acknowledgement and validation.
- When automatic message acknowledgement is enabled, an ACK is immediately sent back to the client after receiving a message.
- When automatic message acknowledgement is disabled, user is given control to send back an ACK/NACK message from an ESB sequence after any message validations or related tasks. Different types of message validations done at the message builder are removed for behavioral consistency of the message builder with the transport.
Some example usage scenarios are given below:
1. When using a transport such as HTTP, to create an ACK/NACK message from an HL7 message in the flow, specify an axis2 scope message context property "HL7_GENERATE_ACK", and set its value to true. It ensures that an ACK/NACK message is created automatically when a message is sent out (using the HL7 formatter). By default, an ACK message is created. If a NACK message is required to be generated, the message context properties "HL7_RESULT_MODE" and "HL7_NACK_MESSAGE" have to be used.
2. Adding two new service-level parameters to be used by a proxy service.
<proxy>... <parameter name="transport.hl7.AutoAck">true|false</parameter> <!-- default is true --> <parameter name="transport.hl7.ValidateMessage">true|false</parameter> <!-- default is true --> </proxy>
3. When ‘AutoAck’ is false, the following properties can be set inside an ESB sequence.
<property name="HL7_RESULT_MODE" value="ACK|NACK" scope="axis2" /> <!-- notice the properties should be in axis2 scope -->
4. When the result mode is ‘NACK’, following property can be used to give a custom description of the error message.
<property name="HL7_NACK_MESSAGE" value="<ERROR MESSAGE>" scope="axis2" />
5. The property "HL7_RAW_MESSAGE" in the axis2 scope can be used to retrieve the original raw EDI format HL7 message in an ESB sequence. As the user doesn't have to again convert from XML to EDI, this usage may be particularly helpful inside a custom mediator.
Synchronization with Builder/Formatter
The transport listener/sender, message builder/formatter uses a common implementation of parsing/validation logic of HL7 messages. Set the Java system property "ca.uhn.hl7v2.llp.charset" to control the encoding type of incoming messages. More information about this configuration will be coming up soon.