docs: public void displayDialog() {
  
          if (DIALOG_CHANGEITEMTITLE.equals(getParamAction())) {
              // build the JSON object for the current item with changed title property
              changeItemTitle(getJsp().getRequest().getParameter(PARAM_ITEMPATH));
          } else if (DIALOG_CHANGEITEMLINKURL.equals(getParamAction())) {
              // build the JSON object for the current item with changed resource content (CmsResourcePointer)
              changeItemLinkUrl(getJsp().getRequest().getParameter(PARAM_ITEMPATH));
          } else if (DIALOG_GETCATEGORIES.equals(getParamAction())) {
              // get the available categories as JSON array
              buildJsonCategoryList();
          } else if (DIALOG_GETGALLERIES.equals(getParamAction())) {
              // get the available galleries as JSON array
              buildJsonGalleryList();
          } else if (DIALOG_GETGALLERY.equals(getParamAction())) {
              // get the desired gallery as JSON object
              buildJsonGalleryItem(getJsp().getRequest().getParameter(PARAM_GALLERYPATH));
          } else if (DIALOG_GETITEMS.equals(getParamAction())) {
              if (LISTMODE_CATEGORY.equals(getParamListMode())) {
                  // get the items of selected category
                  buildJsonResourceItems(getCategoryItems(), null);
              } else {
                  // get the items of a selected gallery
                  buildJsonResourceItems(getGalleryItems(), getParamGalleryPath());
              }
          } else if (DIALOG_GETACTIVEITEM.equals(getParamAction())) {
              // build the JSON object for the currently active item
              buildJsonActiveItem(getJsp().getRequest().getParameter(PARAM_ITEMPATH));
          }
      }