code: @Override
  	public List<T> getForIdentifiers(Collection<X> ids) {
  		if(AssertUtils.isEmpty(ids)) {
  			return null;
  		}
  		
  		if(this.idKey == null) {
  			fetchMappingContextAndConversionService();
  		}
  		
  		Query query = new Query(Criteria.where(this.idKey).in(ids));
  		return this.mongoTemplate.find(query, this.entityClass);
  	}
docs: Get all records for the given {@link Collection} of primary keys.
  
  @param ids
  the {@link Collection} of keys
  
  @return a {@link List} of available records