How to override custom Jackson deserializer in child project? - spring

Question

In our company library (say lib-a) we have an interface:
public interface MyInterface {
...
}
and its default implementation:
public enum DefaultMyImpl implements MyInterface {
...
}
a serializer for it:
public class DefaultMyInterfaceSerializer extends JsonDeserializer<MyInterface> {
#Override
public MyInterface deserialize(JsonParser parser, DeserializationContext context) throws IOException {
return parser.readValuesAs(DefaultMyImpl.class).next();
}
}
and for Jackson we have:
#Bean
public Jackson2ObjectMapperBuilderCustomizer defaultObjectMapperBuilderCustomizer() {
return builder -> builder
.deserializerByType(MyInterface.class, new DefaultMyInterfaceSerializer());
}
and in a child project that has a dependency on lib-a, we might have another implementation:
public enum ChildMyImpl implements MyInterface {
...
}
and a serializer for it:
public class ChildMyInterfaceSerializer extends JsonDeserializer<MyInterface> {
#Override
public MyInterface deserialize(JsonParser parser, DeserializationContext context) throws IOException {
return parser.readValuesAs(ChildMyImpl.class).next();
}
}
and it's related Jackson configuration:
#Bean
public Jackson2ObjectMapperBuilderCustomizer childObjectMapperBuilderCustomizer() {
return builder -> builder
.deserializerByType(MyInterface.class, new ChildMyInterfaceDeserializer());
}
However, I don't seem to be able to override Jackson2ObjectMapperBuilder deserializer for MyInterface. I'm getting this Http 400 error on deserialization:
Bad Request: JSON parse error: Cannot deserialize value of type `com.company.library.domain.DefaultMyImpl` from String "SOME_STRING": not one of the values accepted for Enum class: [DEFAUL_ENUM_VAL]
at [Source: (PushbackInputStream); line: 1, column: 30]; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Cannot deserialize value of type `com.company.library.domain.DefaultMyImpl` from String "SOME_STRING": not one of the values accepted for Enum class: [DEFAUL_ENUM_VAL]
at [Source: (PushbackInputStream); line: 1, column: 30] (through reference chain: com.company.library.domain.MyInterface["..."])
Thinking it is because the customizer in the library overrides the child project's I've tried putting:
#DependsOn(value = "defaultObjectMapperBuilderCustomizer")
or
#Order(value = Ordered.HIGHEST_PRECEDENCE)
on top of child customizer #Bean to no avail. How do I order them in the way that child project overrides the one in the dependency (lib-a)?

Answer 1

I had to implement BeanPostProcessor and override it there:
#Configuration
public class FinalJacksonConfiguration implements BeanPostProcessor {
#Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
if (bean instanceof Jackson2ObjectMapperBuilder) {
final Jackson2ObjectMapperBuilder builder = (Jackson2ObjectMapperBuilder) bean;
builder.serializerByType(MyInterface.class, new ChildMyInterfaceDeserializer());
}
return bean;
}
}