docs: public void open(String location, String target, final Runnable onFailure) {
  
          String id = RandomStringUtils.randomAlphanumeric(16);
          m_callbackMap.put(id, new FutureCallback<Boolean>() {
  
              public void onFailure(Throwable t) {
                  //
              }
  
              public void onSuccess(Boolean result) {
  
                  if (!result.booleanValue()) {
                      onFailure.run();
                  }
              }
          });
          getRpcProxy(I_CmsWindowClientRpc.class).open(location, target, id);
      }