code: private void initTopicTree() {
          try {
              Object data = view.getViewData();
              
              if (!(data instanceof TopicTree)) {
                  return;
              }
              
              TopicTree topicTree = (TopicTree) data;
              HelpTopicNode baseNode;
              
              if (helpViewType == HelpViewType.TOC) {
                  HelpTopic topic = new HelpTopic(null, hs.getName(), hs.getName());
                  baseNode = new HelpTopicNode(topic);
                  rootNode.addChild(baseNode);
              } else {
                  baseNode = rootNode;
              }
              
              initTopicTree(baseNode, topicTree.getRoot());
              
          } catch (IOException e) {
              return;
          }
          
      }
docs: Initialize the topic tree.