code: public Collection<JavaClassSource> allResources()
     {
        Set<JavaClassSource> result = new HashSet<>();
        for (DTOPair pair : dtos.values())
        {
           if (pair.rootDTO != null)
           {
              result.add(pair.rootDTO);
           }
           if (pair.nestedDTO != null)
           {
              result.add(pair.nestedDTO);
           }
        }
        return result;
     }
docs: Retrieves all the DTOs present in this instance.
  
  @return A {@link Collection} of all the DTOs present in this {@link DTOCollection} instance.