code: public IGeneratorSet getGenerators() {
      if( generatorSet_ == null && generatorSetRef_ != null)
        {
        try( GeneratorSetResource resource = GeneratorSetResource.at( urlFor( generatorSetRef_)))
          {
          generatorSet_ = resource.getGeneratorSet();
          }
        catch( Exception e)
          {
          throw new GeneratorSetException( String.format( "Can't read resource at %s", generatorSetRef_), e);
          }
        }
      return generatorSet_;
      }
docs: Returns the generator set for this project.