小编use*_*411的帖子

我有一些类:SearchResponse,SearchResponseHit,SpecialSearchResponse(扩展SearchResponse)和SpecialSearchResponseHit(扩展SearchResponseHit).

SearchResponse看起来像这样:

public class SearchResponse implements Iterable<SearchResponseHit> {

    [...]

    public Iterator<SearchResponseHit> iterator() {
        return searchResponseHits.iterator();
    }
}

这使我可以在foreach循环中使用SearchResponse的实例,如下所示:

for (SearchResponseHit hit : mySearchResponse) {
    [...]
}

现在,当我有一个SpecialSearchResponse实例时,我想做的,但无法弄清楚如何编译这段代码:

for (SpecialSearchResponseHit specialHit : mySpecialSearchResponse) {
    [...]
}

这给了我以下编译器错误:

Type mismatch: cannot convert from element type SearchResponseHit to SpecialSearchResponseHit

如果我尝试将此代码添加到SpecialSearchResponse:

public Iterator<SpecialSearchResponseHit> iterator() {
    [...]
}

......我收到错误:

The return type is incompatible with Iterable<SearchResponseHit>.iterator()

我尝试将SearchResponse中的方法更改为:

    public Iterator<? extends SearchResponseHit> iterator() {
        return searchResponseHits.iterator();
    }

......但这给了我错误:

The return type is incompatible with Iterable<SearchResponseHit>.iterator()

然后我尝试将类定义更改为: …