Many to One Assistance

[Stefan du Preez]

Hi,

I am quite new to Spring and Mapstruct, I am not sure if this is the correct place to ask this, but I have the following use case I really need assistance with:

It is the typical Many-To-One use case, with added fields. 

Json_object and json_attribute are both mapped by using MapStruct. 

I am using @EmbeddedId on the JsonMapping entity.

If I write the JsonMappingMapper manually I can get it to work, but nowhere can I find anything about mapping Composite Keys in MapStruct.

 I need to figure out how to get MapStruct to generate the following to be able to save changes on the json_mapping table:

public JsonMapping dtoToEntity(JsonObject jsonObject, JsonMappingDto dto) {
 JsonMappingId id = new JsonMappingId(jsonObject.getJsonObjectId(), dto.getJsonAttribute().getJsonAttrId());
 JsonMapping entity = jsonMappingRepository.findOne(id);
 if (entity == null) {
   entity = new JsonMapping();
 }
 entity.setId(new JsonMappingId(jsonObject.getJsonObjectId(), dto.getJsonAttribute().getJsonAttrId()));
 entity.setJsonAttribute(jsonAttributeMapper.dtoToEntity(dto.getJsonAttribute()));
 entity.setJsonObject(jsonObject);
 return entity;
 }

Any help would be greatly appreciated :)

Regards

Stefan du Preez

[Sjaak Derksen]

For my understanding:

Is this a one-time-problem -> don't bother. Use the manual mapping method above.

Is this a recurring-problem -> you might want to look into @BeforeMapping. This way you can delegate fetching the entity (http://mapstruct.org/documentation/stable/reference/html/#customizing-mappings-with-before-and-after) and setting the id to a specific method. If you have control over the `JsonMapping`  and the `JsonObject` you can probably generalise this into an interface.

[Sjaak Derksen]

On Saturday, March 17, 2018 at 11:26:36 AM UTC+1, Sjaak Derksen wrote:

For my understanding:

Is this a one-time-problem -> don't bother. Use the manual mapping method above.

Is this a recurring-problem -> you might want to look into @BeforeMapping. This way you can delegate fetching the entity (http://mapstruct.org/documentation/stable/reference/html/#customizing-mappings-with-before-and-after) and setting the id to a specific method. If you have control over the `JsonMapping`  and the `JsonObject` you can probably generalise this into an interface.

@ObjectFactory is a better option.. I added an example: https://github.com/mapstruct/mapstruct-examples/pull/39

[Sjaak Derksen]

PR merged: https://github.com/mapstruct/mapstruct-examples/tree/master/mapstruct-lookup-entity-with-id