code: protected DefaultArtefactInfo getArtefactInfo(String artefactType, boolean create) {
          DefaultArtefactInfo cache = (DefaultArtefactInfo) artefactInfo.get(artefactType);
          if (cache == null && create) {
              cache = new DefaultArtefactInfo();
              artefactInfo.put(artefactType, cache);
              cache.updateComplete();
          }
          return cache;
      }
docs: Get or create the cache of classes for the specified artefact type.
  
  @param artefactType The name of an artefact type
  @param create       Set to true if you want non-existent caches to be created
  @return The cache of classes for the type, or null if no cache exists and create is false