start

startDesign.java

public class EntityServiceImp implements EntityService {

    private EntityRepository repository;
    private ImageService imageService;

    @Override
    public void update(String id, UpdateData updateData) {
        Entity entity = repository.find(id);
        entity.setDescription(updateData.getDescription());
        entity.setTitle(updateData.getTitle());
        imageService.updateImage(entity, updateData);
        repository.save(entity);
    }

}

public class ImageServiceImpl implements ImageService {

    private ImageStoreGateway imageStoreGateway;

    @Override
    public void updateImage(Entity entity, UpdateData updateData) {
        if (updateData.getImageUrl() != null) {
            ImageEntity imageEntity = new ImageEntity();
            imageEntity.setImageUrl(updateData.getImageUrl());
            imageStoreGateway.postImage(imageEntity);
            ImageEntity previous = entity.getImage();
            imageStoreGateway.deleteImage(previous);
            entity.setImage(imageEntity);
        }
    }
}