code: public static List<Class<? extends WindupVertexFrame>> getMappings(GraphRewrite event, String pattern)
      {
          Map<String, List<Class<? extends WindupVertexFrame>>> mappings = getMappings(event);
          List<Class<? extends WindupVertexFrame>> result = mappings.get(pattern);
          if (result == null)
          {
              result = new ArrayList<>();
              mappings.put(pattern, result);
          }
          return result;
      }
docs: Get the list of {@link WindupVertexFrame} type mappings for the given pattern and {@link GraphRewrite} event.