The hl7 component is used for working with the HL7 MLLP protocol and the HL7 model using the HAPI library.
This component supports the following:
HL7 MLLP codec for Mina.
Agnostic data format using either plain String objects or HAPI HL7 model objects.
Type Converter from/to HAPI and String.
HL7 DataFormat using HAPI library.
Even more easy-of-use as it is integrated well with the camel-mina component.
Maven users will need to add the following dependency to their pom.xml
for this component:
<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-hl7</artifactId> <version>x.x.x</version> <!-- use the same version as your Camel core version --> </dependency>
HL7 is often used with the HL7 MLLP protocol that is a text based TCP socket based protocol. This component ships with a Mina Codec that conforms to the MLLP protocol so you can easily expose a HL7 listener that accepts HL7 requests over the TCP transport.
To expose a HL7 listener service we reuse the existing camel-mina component where we just use the HL7MLLPCodec
as
codec.
The HL7 MLLP codec has the following options:
Name | Default Value | Description |
---|---|---|
startByte
|
0x0b
|
The start byte spanning the HL7 payload. Is the HL7 default value of
0x0b (11 decimal). |
endByte1
|
0x1c
|
The first end byte spanning the HL7 payload. Is the HL7 default value of
0x1c (28 decimal). |
endByte2
|
0x0d
|
The 2nd end byte spanning the HL7 payload. Is the HL7 default value of
0x0d (13 decimal). |
charset
|
JVM Default | The encoding (is a charset name) to use for the codec. If not provided, Fuse Mediation Router will use the JVM default Charset. |
convertLFtoCR
|
true
|
Will convert \n to \r (0x0d ,
13 decimal) as HL7 usually uses \r as segment terminators. The HAPI
library requires the use of \r . |
validate
|
true
|
Fuse Mediation Router 2.0: Whether HAPI Parser should validate or not. |
In our Spring XML file, we configure an endpoint to listen for HL7 requests using TCP:
<endpoint id="hl7listener" uri="mina:tcp://localhost:8888?sync=true&codec=#hl7codec"/>
Notice we configure it to use camel-mina with TCP on
the localhost
on port 8888
. We use sync=true to indicate that this listener is synchronous and therefore will
return a HL7 response to the caller. Then we set up mina to use our HL7 codec with codec=#hl7codec. Notice that hl7codec
is just a
Spring bean ID, so we could have named it mygreatcodecforhl7
or whatever.
The codec can also be set up in the Spring XML file:
<bean id="hl7codec" class="org.apache.camel.component.hl7.HL7MLLPCodec"> <property name="charset" value="iso-8859-1"/> </bean>
And here we configure the charset encoding to use, and iso-8859-1
is
commonly used.
The endpoint hl7listener can then be used in a route as a consumer, as this java DSL example illustrates:
from("hl7listener").to("patientLookupService");
This is a very simple route that will listen for HL7 and route it to a service named patientLookupService that is also a Spring bean ID we have configured in the Spring XML as:
<bean id="patientLookupService" class="com.mycompany.healtcare.service.PatientLookupService"/>
And another powerful feature of Fuse Mediation Router is that we can have our busines logic in POJO classes that are not at all tied to Fuse Mediation Router as shown here:
public class PatientLookupService { public Message lookupPatient(Message input) throws HL7Exception { QRD qrd = (QRD)input.get("QRD"); String patientId = qrd.getWhoSubjectFilter(0).getIDNumber().getValue(); // find patient data based on the patient id and create a HL7 model object with the response Message response = ... create and set response data return response }
Notice that this class is just using imports from the HAPI library and none from Fuse Mediation Router.
The HL7MLLP codec uses plain String
as data format. And Fuse Mediation Router uses
Type Converter to convert from/to strings to the HAPI
HL7 model objects. However, you can use the plain String
objects if you
prefer, for instance if you need to parse the data yourself.
See samples for such an example.
The HL7 model is Java objects from the HAPI library. Using this library, we can encode and decode from the EDI format (ER7) that is mostly used with HL7. With this model you can code with Java objects instead of the EDI based HL7 format that can be hard for humans to read and understand.
The ER7 sample below is a request to lookup a patient with the patient ID,
0101701234
.
MSH|^~\\&|MYSENDER|MYRECEIVER|MYAPPLICATION||200612211200||QRY^A19|1234|P|2.4 QRD|200612211200|R|I|GetPatient|||1^RD|0101701234|DEM||
Using the HL7 model we can work with the data as a
ca.uhn.hl7v2.model.Message.Message
object. To retrieve the patient ID for
the patient in the ER7 above, you can do this in java code:
Message msg = exchange.getIn().getBody(Message.class); QRD qrd = (QRD)msg.get("QRD"); String patientId = qrd.getWhoSubjectFilter(0).getIDNumber().getValue();
Fuse Mediation Router has built-in type converters, so when this operation is invoked:
Message msg = exchange.getIn().getBody(Message.class);
Fuse Mediation Router will convert the received HL7 data from String
to
Message
. This is powerful when combined with the HL7 listener, then you
as the end-user don't have to work with byte[]
, String
or any other simple object formats. You can just use the HAPI HL7 model objects.
Key | MSH field | Example |
---|---|---|
hl7.msh.sendingApplication
|
MSH-3
|
MYSERVER
|
hl7.msh.sendingFacility
|
MSH-4
|
MYSERVERAPP
|
hl7.msh.receivingApplication
|
MSH-5
|
MYCLIENT
|
hl7.msh.receivingFacility
|
MSH-6
|
MYCLIENTAPP
|
hl7.msh.timestamp
|
MSH-7
|
20071231235900
|
hl7.msh.security
|
MSH-8
|
null
|
hl7.msh.messageType
|
MSH-9-1
|
ADT
|
hl7.msh.triggerEvent
|
MSH-9-2
|
A01
|
hl7.msh.messageControl
|
MSH-10
|
1234
|
hl7.msh.processingId
|
MSH-11
|
P
|
hl7.msh.versionId
|
MSH-12
|
2.4
|
Key | MSH field | Example |
---|---|---|
CamelHL7SendingApplication
|
MSH-3
|
MYSERVER
|
CamelHL7SendingFacility
|
MSH-4
|
MYSERVERAPP
|
CamelHL7ReceivingApplication
|
MSH-5
|
MYCLIENT
|
CamelHL7ReceivingFacility
|
MSH-6
|
MYCLIENTAPP
|
CamelHL7Timestamp
|
MSH-7
|
20071231235900
|
CamelHL7Security
|
MSH-8
|
null
|
CamelHL7MessageType
|
MSH-9-1
|
ADT
|
CamelHL7TriggerEvent
|
MSH-9-2
|
A01
|
CamelHL7MessageControl
|
MSH-10
|
1234
|
CamelHL7ProcessingId
|
MSH-11
|
P
|
CamelHL7VersionId
|
MSH-12
|
2.4
|
All headers are String
types. If a header value is missing, its value
is null
.
The HL7 Data Format supports the following options:
Option | Default | Description |
---|---|---|
validate | true | Camel 2.0: Whether the HAPI Parser should validate. |
To use HL7 in your camel routes you need to add a dependency on camel-hl7, which implements this data format.
If you use Maven, you could just add the following to your pom.xml
,
substituting the version number for the latest & greatest release (see the download page for the latest versions).
<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-hl7</artifactId> <version>2.2.0</version> </dependency>
Since HAPI 0.6, the library has been split into a base library and several structures libraries, one for each HL7v2 message version:
By default camel-hl7
only references the HAPI base library.
Applications are responsible for including structures libraries themselves. For example, if a
application works with HL7v2 message versions 2.4 and 2.5 then the following dependencies must
be added:
<dependency> <groupId>ca.uhn.hapi</groupId> <artifactId>hapi-structures-v24</artifactId> <version>1.0</version> </dependency> <dependency> <groupId>ca.uhn.hapi</groupId> <artifactId>hapi-structures-v25</artifactId> <version>1.0</version> </dependency>
An OSGi bundle containing the base library, all structures libraries and required dependencies (on the bundle classpath) can be downloaded from the HAPI Maven repository as well.
<dependency> <groupId>ca.uhn.hapi</groupId> <artifactId>hapi-osgi-base</artifactId> <version>1.0.1</version> </dependency>
In the following example we send a HL7 request to a HL7 listener and retrieves a response.
We use plain String
types in this example:
String line1 = "MSH|^~\\&|MYSENDER|MYRECEIVER|MYAPPLICATION||200612211200||QRY^A19|1234|P|2.4"; String line2 = "QRD|200612211200|R|I|GetPatient|||1^RD|0101701234|DEM||"; StringBuilder in = new StringBuilder(); in.append(line1); in.append("\n"); in.append(line2); String out = (String)template.requestBody("mina:tcp://127.0.0.1:8888?sync=true&codec=#hl7codec", in.toString());
In the next sample, we want to route HL7 requests from our HL7 listener to our business
logic. We have our business logic in a plain POJO that we have registered in the registry as
hl7service
= for instance using Spring and letting the bean id =
hl7service
.
Our business logic is a plain POJO only using the HAPI library so we have these operations defined:
public class MyHL7BusinessLogic { // This is a plain POJO that has NO imports whatsoever on Fuse Mediation Router. // its a plain POJO only importing the HAPI library so we can much easier work with the HL7 format. public Message handleA19(Message msg) throws Exception { // here you can have your business logic for A19 messages assertTrue(msg instanceof QRY_A19); // just return the same dummy response return createADR19Message(); } public Message handleA01(Message msg) throws Exception { // here you can have your business logic for A01 messages assertTrue(msg instanceof ADT_A01); // just return the same dummy response return createADT01Message(); } }
Then we set up the Fuse Mediation Router routes using the RouteBuilder
as
follows:
DataFormat hl7 = new HL7DataFormat(); // we setup or HL7 listener on port 8888 (using the hl7codec) and in sync mode so we can return a response from("mina:tcp://127.0.0.1:8888?sync=true&codec=#hl7codec") // we use the HL7 data format to unmarshal from HL7 stream to the HAPI Message model // this ensures that the camel message has been enriched with hl7 specific headers to // make the routing much easier (see below) .unmarshal(hl7) // using choice as the content base router .choice() // where we choose that A19 queries invoke the handleA19 method on our hl7service bean .when(header("CamelHL7TriggerEvent").isEqualTo("A19")) .beanRef("hl7service", "handleA19") .to("mock:a19") // and A01 should invoke the handleA01 method on our hl7service bean .when(header("CamelHL7TriggerEvent").isEqualTo("A01")).to("mock:a01") .beanRef("hl7service", "handleA01") .to("mock:a19") // other types should go to mock:unknown .otherwise() .to("mock:unknown") // end choice block .end() // marhsal response back .marshal(hl7);
Notice that we use the HL7 DataFormat to enrich our Camel Message with the MSH fields preconfigued on the Camel Message. This lets us much more easily define our routes using the fluent builders. If we do not use the HL7 DataFormat, then we do not gains these headers and we must resort to a different technique for computing the MSH trigger event (= what kind of HL7 message it is). This is a big advantage of the HL7 DataFormat over the plain HL7 type converters.
In this sample we use plain String
objects as the data format, that we
send, process and receive. As the sample is part of a unit test, there is some code for
assertions, but you should be able to understand what happens. First we send the plain string,
Hello World
, to the HL7MLLPCodec
and receive the
response as a plain string, Bye World
.
MockEndpoint mock = getMockEndpoint("mock:result"); mock.expectedBodiesReceived("Bye World"); // send plain hello world as String Object out = template.requestBody("mina:tcp://127.0.0.1:8888?sync=true&codec=#hl7codec", "Hello World"); assertMockEndpointsSatisfied(); // and the response is also just plain String assertEquals("Bye World", out);
Here we process the incoming data as plain String and send the response also as plain String:
from("mina:tcp://127.0.0.1:8888?sync=true&codec=#hl7codec") .process(new Processor() { public void process(Exchange exchange) throws Exception { // use plain String as message format String body = exchange.getIn().getBody(String.class); assertEquals("Hello World", body); // return the response as plain string exchange.getOut().setBody("Bye World"); } }) .to("mock:result");