private boolean hasIdleInvokers(){
  for (  AsyncEventListenerInvoker invoker : this.scheduledInvokers) {
    if (invoker.isIdle()) {
      return true;
    }
  }
  return false;
}

private boolean hasIdleInvokers ( ) { for ( AsyncEventListenerInvoker invoker : this . scheduledInvokers ) { if ( invoker . isIdle ( ) ) { return true ; } } return false ; }
determine whether this listener container currently has any idle instances among its scheduled invokers .
