code: public IRenderingElement generateDiagram(T object) {
          ElementGroup diagram = new ElementGroup();
          for (IGenerator<T> generator : this.generators) {
              diagram.add(generator.generate(object, this.rendererModel));
          }
          return diagram;
      }
docs: The main method of the renderer, that uses each of the generators
  to create a different set of {@link IRenderingElement}s grouped
  together into a tree.
  
  @param object the object of type T to draw
  @return the diagram as a tree of {@link IRenderingElement}s