How can I configure Gson to skip serialization of enum values if they are null?

[Yeikel Santana]

I am using open api to generate my model files , running the following snippet : 

java -jar -Dmodels \
-DmodelDocs=false
-DmodelTests=false openapi-generator-cli-4.3.0.jar \
generate -i swagger.yaml -g java --model-package=c
models --additional-properties dateLibrary=java8-localdatetime,useBeanValidation=true,hideGenerationTimestamp=true \
--output=../../../

When I use open api generator, it generates the following TypeAdapter for my enum.

public static class Adapter extends TypeAdapter<CodesEnum> {
      @Override
      public void write(final JsonWriter jsonWriter, final CodesEnum enumeration) throws IOException {
        jsonWriter.value(enumeration.getValue());
      }

My CodesEnum are optional in my schema, so they can be

null

. Issue is that we I try to serialize the object using toJson, for cases when enumeration is null , it generates a null pointer exception.

String json = GSON.toJson(request);


java.lang.NullPointerException
    models.Type$CodesEnum$Adapter.write(Type.java:222)

How can I configure Gson to that it skips the call to

.write

all together?

Thanks