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The template is built of a series of sub-templates
A sub template is responsible for creating each of the main message segments (MSH, PID, PV1, ORC, OBR and OBX)
Each sub template may be in turn composed of several other sub templates.
The MSH segment is made up of all constants, and hence may not need to be composed of other segments.
The OBR segment is used to represent an OpenMRS obs group
Converting the xml version of the hl7 message into the pipe delimited format.
1. Convert the xml object into string
2. Convert the string into the HAPI object
3. Use HAPI to convert the hl7 message into the pipe delimited format
Converting an hl7 String into the HAPI object
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public Message processMessage(String hl7, String enterpriseId) throws HL7Exception {
log.debug("Register handler applications for R01 and A28");
// TODO draw registered applications from database or configuration file
router = new MessageTypeRouter();
router.registerApplication("ORU", "R01", new RHEA_ORU_R01Handler(enterpriseId));
// First, try and parse the message
Message message;
try {
message = parser.parse(hl7);
}
catch (EncodingNotSupportedException e) {
throw new HL7Exception("HL7 encoding not supported", e);
}
catch (HL7Exception e) {
throw new HL7Exception("Error parsing message", e);
}
return response;
}
}
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Converting the HAPI object into the pipe delimited format is done using a HAPI PipeParser
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PipeParser parser = new PipeParser();
String msg = null;
try {
msg = parser.encode(r01String);
}
catch (HL7Exception e) {
log.error("Exception parsing constructed message.");
}
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pseudo-template for a R01 message (contributed by Darius)
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public class Hl7MessageGeneratorTest {
Map<String, Object> defaultBindings;
@Before
public void beforeEachTest() throws Exception {
// build a Patient and an Encounter in-memory
}
/**
* Each template that we're going to write should be developed based on a test like this.
* Basically you can build and debug the whole thing without ever even having to fully build the
* module.
*/
public void testPatientIdentifierToCxTemplate() throws Exception {
Hl7MessageGenerator mock = Mockito.mock(Hl7MessageGenerator.class);
when(mock.getTemplate("PatientIdentifier-to-CX")).thenReturn(patientIdentifierToCxTemplate());
Map<String, Object> bindings = new HashMap<String, Object>();
bindings.put("patientIdentifier", buildPatientIdentifier());
String output = mock.applyTemplate("PatientIdentifier-to-CX", bindings);
Assert.assertEquals("<CX>what it should look like</CX>", output);
}
/**
* I've put this in its own method because we know that higher-level templates (e.g. Patient-to-PID)
* will also need to include this same template.
*/
private String patientIdentifierToCxTemplate() {
return "Template goes here, maybe you want to actually load it from an XML file";
}
private PatientIdentifier buildPatientIdentifier() {
// TODO
}
}
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Converting the xml version of the hl7 message into the pipe delimited format.
1. Convert the xml object into string
2. Convert the string into the HAPI object
3. Use HAPI to convert the hl7 message into the pipe delimited format
Converting an hl7 String into the HAPI object
| Code Block |
|---|
public Message processMessage(String hl7, String enterpriseId) throws HL7Exception { log.debug("Register handler applications for R01 and A28"); // TODO draw registered applications from database or configuration file router = new MessageTypeRouter(); router.registerApplication("ORU", "R01", new RHEA_ORU_R01Handler(enterpriseId)); router.registerApplication("ADT", "A28", new ADTA28Handler()); // TODO: any pre-parsing for HL7 messages would go here // First, try and parse the message Message message; try { message = parser.parse(hl7); } catch (EncodingNotSupportedException e) { throw new HL7Exception("HL7 encoding not supported", e); } catch (HL7Exception e) { throw new HL7Exception("Error parsing message", e); } // TODO: any post-parsing (pre-routing) processing would go here // If parsing succeeded, then try to route the message Message response; try { if (!router.canProcess(message)) throw new HL7Exception("No route for message"); response = router.processMessage(message); } catch (ApplicationException e) { throw new HL7Exception("Error routing HL7 message", e); } return response; } } |