How to use

onAction

method

in

org.eclipse.che.ide.ui.menubutton.ActionHandler

 @Override
 public void actionPerformed(ActionEvent e) {
  itemsProvider
    .getDefaultItem()
    .ifPresent(
      defaultItem ->
        getActionHandler().ifPresent(handler -> handler.onAction(defaultItem)));
 }
}

 MainButton(SafeHtml content) {
  super(Document.get().createDivElement());
  getElement().setInnerSafeHtml(content);
  addStyleName(RESOURCES.css().button());
  addStyleName(RESOURCES.css().mainButton());
  addClickHandler(
    event -> {
     if (menu != null && menu.isShowing()) {
      return;
     }
     final Optional<MenuItem> defaultItem = itemsProvider.getDefaultItem();
     if (defaultItem.isPresent()) {
      getActionHandler()
        .ifPresent(actionHandler -> actionHandler.onAction(defaultItem.get()));
     } else {
      showMenu();
     }
    });
 }
}

private void attachEventHandlers() {
 addDomHandler(
   event -> {
    if (overItem != null) {
     overItem.removeStyleName(resources.css().popupItemOver());
    }
    overItem = ItemWidget.this;
    addStyleName(resources.css().popupItemOver());
    if (childList != null) {
     childList.hide();
    }
    if (dataProvider.isGroup(item)) {
     Pair<List<MenuItem>, String> children = dataProvider.getChildren(item);
     createChildPopup(children);
    }
   },
   MouseOverEvent.getType());
 addDomHandler(
   event -> {
    if (dataProvider.isGroup(item)) {
     return;
    }
    hide(true);
    getActionHandler().ifPresent(actionHandler -> actionHandler.onAction(item));
   },
   ClickEvent.getType());
}