code: public GrailsClass getArtefact(String artefactType, String name) {
          ArtefactInfo info = getArtefactInfo(artefactType);
          return info == null ? null : info.getGrailsClass(name);
      }
docs: Retrieves an artefact for the given type and name.
  
  @param artefactType The artefact type as defined by a registered ArtefactHandler
  @param name         The name of the class
  @return A GrailsClass instance or null if none could be found for the given artefactType and name