Conformance Class Generator

HAPI 1.1 introduced a new conformance class generator, which takes a conformance profile and generates a HAPI message definition. This is useful both to constrain/remove unwanted elements from a message type, as well as to extend a message type by adding custom segments.

This feature was developed by University Health Network, and is currently being used quite heavily in a production ESB/interface engine to create message structures for translating messages between arbitrary formats. Applications that can produce message with custom Z-segments, out of order segments, and other nuances are no longer an issue.

For a complete reference on how the plugin works, check out the Maven Plugin Documentation

Important: Note that this functionality is still a work in progress, and has the following limitations:

• Fields which are marked as "not used" are not yet constrained away. As such, this plugin is really currently only useful for extending existing message types, not constraining them. Constraining is the next planned use-case for implementation. Get in touch if you would like to help.
• The new generator is only provided as a Maven plugin. Converting it to work with Ant or as a standalone application would be fairly easy, please get in touch if you would like to contribute.

  src/main/conf/conf.xml

<plugins>
  <plugin>
    <groupId>ca.uhn.hapi</groupId>
    <artifactId>hapi-sourcegen</artifactId>
    <version>${hapi.version}</version>
    <executions>
      <execution>
        <phase>generate-sources</phase>
        <goals>
          <goal>confgen</goal>
        </goals>
        <configuration>

          <!-- This is the conformance profile file to use -->
          <profile>${basedir}/src/main/resources/example_ack.xml</profile>

          <!-- Place generated Java source here -->
          <targetDirectory>${basedir}/target/generated-sources/confgen</targetDirectory>

          <!-- Generated classes will be placed here -->
          <packageName>com.foo</packageName>

       </configuration>
      </execution>
    </executions>
  </plugin>
</plugins>  

target/generated-sources/confgen

Runtime Message Validator

The Default Validator accepts a conformance profile and validates a message against it at runtime. Example usage:

// Load the profile from the classpath
ProfileParser parser = new ProfileParser(false);
RuntimeProfile profile = parser.parseClasspath("ca/uhn/hl7v2/conf/parser/example_ack.xml");

// Create a message to validate
String message = "MSH|^~\\&|||||||ACK^A01|1|D|2.4|||||CAN|wrong|F^^HL70001^x^^HL78888|\r"; //note HL7888 doesn't exist
ACK msg = (ACK) (new PipeParser()).parse(message);

// Validate
HL7Exception[] errors = new DefaultValidator().validate(msg, profile.getMessage());

// Each exception is a validation error
System.out.println("Validation errors: " + Arrays.asList(errors));