[Micronaut] Improving micronaut-model and micronaut-client generation

[DmitryKubahov]

These improvements are related only to the java-micronaut generator.

Model generating change:

• Adding a new parameter serializationLibrary. Right now it contains only 2 values: jackson and micronaut_serde_jackson. Jackson is the default one and does not change anything. micronaut_serde_jackson - Micronaut Serialization with support of jackson annotation. This library supports not all jackson annotations feature - limitation.

Client generating change:

• new additionalClientTypeAnnotations parameter. As micronaut-client generator will declarative http client and it is really nice to have the opportunity to add custom/additional annotations to it.

@andriy-dmytruk please, take a look.

[andriy-dmytruk]

Hi @DmitryKubahov. Thank you for the PR. Implementation looks good.

Could you also take a look at these annotations unsupported by micronaut serialization: micronaut-projects/micronaut-serialization#286. These seem to have pretty simple fixes related to your PR:

• The @JsonTypeInfo annotation is created in the common/model/typeInfoAnnotation.mustache and needs the removal of , visible=true.
• The @JsonDeserialize is added in the AbstractJavaCodegen with the x-setter-extra-annotation parameter:

  if ("set".equals(property.containerType)) {
                model.imports.add("LinkedHashSet");
                boolean canNotBeWrappedToNullable = !openApiNullable || !property.isNullable;
                if (canNotBeWrappedToNullable) {
                    model.imports.add("JsonDeserialize");
                    property.vendorExtensions.put("x-setter-extra-annotation", "@JsonDeserialize(as = LinkedHashSet.class)");
                }
            }
  

  We could fix this in the common/model/pojo.mustache file by putting this block

  {{#vendorExtensions.x-setter-extra-annotation}}
      {{{vendorExtensions.x-setter-extra-annotation}}}  
  {{/vendorExtensions.x-setter-extra-annotation}}
  

  inside the {{#jackson}} block above.

[andriy-dmytruk]

It would also be beneficial to change the build.gradle and pom.xml mustache files to include the serialization-jackson feature as dependency similar to how micronaut launcher does it.

Changes would need to include the following:

• DIFF with micronaut serialization, gradle
• DIFF with micronaut serialization, maven

@DmitryKubahov Could you take a look at that? Use the OpenAPI generator slack if you need to discuss anything with me.

[DmitryKubahov]

@andriy-dmytruk I made all the changes according to your comments, please, check them.

[andriy-dmytruk]

Thanks @DmitryKubahov. LGTM
@wing328 Could you please merge?