not support AbstractAuditable(Optional<MyEntity> getter) [DATAREST-1490]

john-huang-onon opened DATAREST-1490 and commented

if my Entity associate with other Entity,
like extends org.springframework.data.jpa.domain.AbstractAuditable that contain createdBy(or lastModifiedBy) field,
and the getter of field is defined as "public Optional<OtherEntity> getCreatedBy()",
will occur "java.lang.IllegalArgumentException: Couldn't find PersistentEntity for type class java.util.Optional!"

 

then I check and try:

• org.springframework.data.rest.webmvc.config.RepositoryRestMvcConfiguration

mapper has registerModule(jdk8Module)

 

• config to registerModule SimpleModule(.addSerializer(Optional.class)), all invalid

implements org.springframework.data.rest.webmvc.config.RepositoryRestConfigurer
RepositoryRestConfigurerAdapter is deprecated
extends org.springframework.data.rest.webmvc.config.RepositoryRestMvcConfiguration

 

• at runtime, com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField() will invoke ser.serialize()

this ser is not assign as jdk8Module or configured-my-custom-serializer, is org.springframework.data.rest.webmvc.json.PersistentEntityJackson2Module.NestedEntitySerializer

 

• as stated before, I find out

org.springframework.data.rest.webmvc.json.PersistentEntityJackson2Module.AssociationOmittingSerializerModifier.changeProperties() will check .isEntity() then .assignSerializer(this.nestedEntitySerializer)
so Serializer always not use jdk8Module or configured-my-custom-serializer
so if the field is String, and getter is Optional<String> will work normally

 

• use @JsonSerialize(using = MyOptionalJsonSerializer.class) to specify at getter

will occur "java.lang.IllegalStateException: Cannot override _serializer: had a my.package.config.MyOptionalJsonSerializer, trying to set to org.springframework.data.rest.webmvc.json.PersistentEntityJackson2Module$NestedEntitySerializer"
cause the logic in "com.fasterxml.jackson.databind.ser.BeanPropertyWriter.assignSerializer()", is not allow change _serializer when _serializer is not null (_serializer allready assign as NestedEntitySerializer)

 

I suggest:

• adopt a unified, don't use Optional-return-getter on associate-entity in entity
• make Spring Data REST support
• tell me the right way to resolve it, please forgive me for being foolish

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