code: public void addEntity(String alias, String entityName) {
      EntityType entityType = Model.getType(entityName);
      if (null == entityType) { throw new RuntimeException("cannot find entity type for " + entityName); }
      entityTypes.put(alias, entityType);
    }
docs: <p>
  addEntity.
  </p>
  
  @param alias a {@link java.lang.String} object.
  @param entityName a {@link java.lang.String} object.