Map lists

[hypercube-software]

It seems that mapping lists is not really possible, the generated code is not able to understand the type of the list:

public List<MyTarget> mapListToList(final List<MySource> source) {
       return conversionService.convert(source,List.class)
}

I have also the same generated method 2 times if I have the conversion in the both directions. the compiler end up saying "name clash: mapListToList.... and mapListToList have the same type erasure"

For lists, another method should be used in the interface ConversionService (see this stackoverflow):

Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType)

It would be nice if the documentation could say something about this

[Chessray]

This is a funny one. The linked solution using TypeDescriptors relies on another Spring-internal mechanism.

Looking at this a bit closer: What is your actual use case? Are you trying to define a Converter<List<A>, List<B>>?

[hypercube-software]

indeed, I just want to convert a List to a List

[coding-guo]

I have the same problem,I want to achieve such a requirement，I defined two mapper

First:
@Mapper(componentModel = "spring") public interface AreaMapperStruct extends Converter<List<Area>, List<AreaSimpleOutDTO>> { @Override List<AreaSimpleOutDTO> convert(List<Area> areaList); }

The second：
@Mapper(componentModel = "spring") public interface PartTypeMapperStruct extends Converter<List<PartType>, List<PartTypeOut>> { @Override List<PartTypeOut> convert(List<PartType> partTypes); }
Compile Error：
`public class ConfigurationServiceAdapter {
private final ConversionService conversionService;

public ConfigurationServiceAdapter(
@qualifier("partTypeConversionService") @lazy final ConversionService conversionService) {
this.conversionService = conversionService;
}

public List mapListToList(final List source) {
return conversionService.convert(source, List.class);
}

public DeviceBrand mapDeviceBrandOptDTOToDeviceBrand(final DeviceBrandOptDTO source) {
return conversionService.convert(source, DeviceBrand.class);
}

public AlarmCode mapAlarmCodeOptDTOToAlarmCode(final AlarmCodeOptDTO source) {
return conversionService.convert(source, AlarmCode.class);
}

public List mapListToList(final List source) {
return conversionService.convert(source, List.class);
}
}`

have two "mapListToList" method，how can i solve this problem

[Chessray]

Will have to look into this a bit. Until we can provide a full solution, the best thing I can suggest is not implementing the List Mapper as a Spring Converter and following standard MapStruct instead.

[coding-guo]

Thank you and look forward to a better solution！！

Will have to look into this a bit. Until we can provide a full solution, the best thing I can suggest is not implementing the List Mapper as a Spring Converter and following standard MapStruct instead.

[Chessray]

Some notes:

• The method TypeDescriptor.collection explicitly states that it's only applicable to anything extending the Collection interface. We should be able to check that.
• Cater for nested Generics, e.g. List<Set<Object>>.
• If we do this, we want to do it right.