未经检查的投射由FindBugs抱怨

Question

请考虑以下代码:

 public void broadcast(FacesEvent event)
    throws AbortProcessingException {

    if(!(event instanceof WrapperEvent)) {
      super.broadcast(event);
      return;
    }

    // Sets up the correct context and fire our wrapped event.
    GridWrapperEvent revent = (GridWrapperEvent)event; // FindBugs is complaining here 
    int oldRowIndex = getRowIndex();
    int oldColumnIndex = getColumnIndex();
    boolean oldClientIdRewritting = clientIdRewritting;
    setClientIdRewritting(revent.isClientIdRewritting());

    setActiveCell(revent.getRowIndex(), revent.getColumnIndex());

    FacesEvent rowEvent = revent.getFacesEvent();
    rowEvent.getComponent().broadcast(rowEvent);
    setActiveCell(oldRowIndex, oldColumnIndex);
    setClientIdRewritting(oldClientIdRewritting);
  }

FindBugs抱怨注释行.我能做些什么吗？这就是FindBugs所说的:

未选中/未确认的 强制转换此未强制转换,并非所有类型的实例都可以强制转换为其强制类型.确保您的程序逻辑确保此强制转换不会失败.

Answer 1

如果你知道这event将永远是一个GridWrapperEvent,你可以忽略警告.否则你可以将一个强制转换(以及依赖它的逻辑)包装在一个支票中

if (event instanceof GridWrapperEvent) {
  // ...
}

实际上你已经这样做了,但对于(我假设)更通用的WrapperEvent类.也许您可以调整该检查而不是添加新检查.