private void updateCommand() {
    if (myTargetOperation != null) {
      if (myContext.isMove()) {
        setExecuteEnabled(myContext.isMoveEnabled() && myTargetOperation.canExecute());
      }
      else if (myContext.isAdd()) {
        setExecuteEnabled(myContext.isAddEnabled() && myTargetOperation.canExecute());
      }
      else if (myContext.isCreate()) {
        setExecuteEnabled(myTargetOperation.canExecute());
      }
      else {
        setExecuteEnabled(false);
      }
    }
    else {
      setExecuteEnabled(false);
    }
  }
private void updateCommand()