code: void updateGalleryData(final boolean viewChanged, final Runnable nextAction) {
  
          CmsRpcAction<CmsContainerPageGalleryData> dataAction = new CmsRpcAction<CmsContainerPageGalleryData>() {
  
              @Override
              public void execute() {
  
                  getContainerpageService().getGalleryDataForPage(
                      getEditableContainers(),
                      getElementView().getElementViewId(),
                      CmsCoreProvider.get().getUri(),
                      getData().getLocale(),
                      this);
              }
  
              @Override
              protected void onResponse(CmsContainerPageGalleryData result) {
  
                  m_handler.m_editor.getAdd().updateGalleryData(result, viewChanged);
                  if (nextAction != null) {
                      nextAction.run();
                  }
              }
          };
          dataAction.execute();
      }
docs: Updates the gallery data according to the current element view and the editable containers.<p>
  This method should only be called from the gallery update timer to avoid unnecessary requests.<p>
  
  @param viewChanged <code>true</code> in case the element view changed
  @param nextAction the action to execute after updating the gallery data