Micronaut Codegen

OpenAPI code generator for Micronaut 4. Micronaut 3 is supported by version 3.x

Include in your pom.xml:

<plugin>
 <groupId>org.openapitools</groupId>
 <artifactId>openapi-generator-maven-plugin</artifactId>
 <version>${version.org.openapitools.generator}</version>
 <executions>
  <execution>
   <goals>
    <goal>generate</goal>
   </goals>
  </execution>
 </executions>
 <configuration>
  <generatorName>micronaut</generatorName>
  <output>${project.build.directory}</output>
  <inputSpec>src/resources//openapi/spec.yaml</inputSpec>
  <packageName>changeMe</packageName>
 </configuration>
 <dependencies>
  <dependency>
   <groupId>io.kokuwa.micronaut</groupId>
   <artifactId>micronaut-openapi-codegen</artifactId>
   <version>${version.io.kokuwa.micronaut.codegen}</version>
  </dependency>
 </dependencies>
</plugin>

Features

• generate api interfaces (see declarative client)
• generate model objects with fluent and property accessors
• generate interfaces for api tests based on method name and return code
• generate client interfaces with micronaut clientId
• add validation annotations
• support for One-Of interfaces
• support for additional properties with composed schemas
• generate example instances of the model-objects

Config options

• clientId: id for generated clients (if no client id is provided no interface will be generated)
• serdeable: add @io.micronaut.serde.annotation.Serdeable to models (default true)
• dateTimeRelaxed: add type registrar for relaxed time converter (default true)
• useBeanValidation: generate validation annotations (default true)
• useGenericResponse: return generic container or specific model, e.g. Model vs. HttpResponse<Model> (default true)
• useOptional: optional parameters are generated as java.util.Optional (default true)
• openApiNullable: add container JsonNullable to model objects that are nullable (default true)
• supportAsync: use reactivex return types, see Reactive HTTP Request Processing
• pagable: generate provider for pagable (default false)
• generateExamples: generate example objects for the model, based on example and default values (default false)
• generateConstants: generate constants for model names and api paths (default false)
• generateAuthentication: generate Àuthentication into controller interfaces if response code 401 is present (default false)
• sealed: generate sealed interfaces (default true)
• record: generate records instead of pojos (default false)

For examples see integration tests.

Null handling and default values

Jackson Inclusions:

• required=true & nullable=false: JsonInclude.ALWAYS
• required=true & nullable=true: JsonInclude.ALWAYS
• required=false & nullable=false: JsonInclude.NON_ABSENT
• required=false & nullable=true: JsonInclude.NON_NULL

Container (array/map):

• required=true & nullable=false: empty containers are set as default value
• required=true & nullable=true: containers have no default value
• required=false & nullable=false: containers have no default value
• required=false & nullable=true: containers have no default value

If jacksonDatabindNullable=true is configured always JsonNullable.undefined() is set.

Do not forget to add the dependency to pom.xml:

<dependency>
 <groupId>org.openapitools</groupId>
 <artifactId>jackson-databind-nullable</artifactId>
 <version>0.2.6</version>
</dependency>

And register Jackson Module:

@Factory
public class ApplicationFactory {

 @Singleton
 JsonNullableModule jsonNullableModule() {
  return new JsonNullableModule();
 }
}

Not supported

• no project (e.g. pom.xml) is generated, only interfaces to implement
• no support for java <17