Is it possible to collect a stream to two different collections using one line?

Question

I have the following code: (simplified for bravity)

public void search(Predicate<String> predicate, Elements elements)
{
    List<SearchResult> searchResults = elements.stream()
        .filter(element -> predicate.test(element.ownText()))
        .map(element -> new SearchResult(element.ownText(), element.baseUri(),element.tagName()))
        .collect(Collectors.toList());
}

But now, I want to have another list which would contain all filtered elements without the mapping. Is it possible to do that with a stream, or should I change to a foreach loop for that?

Answer 1

You can collect the elements after filtering and then use this list to map the elements to search results:

public void search(Predicate<String> predicate, Elements elements) {
    List<Element> filteredElements = 
        elements.stream()
                .filter(element -> predicate.test(element.ownText()))
                .collect(Collectors.toList());

    List<SearchResult> searchResults = 
        filteredElements.stream()
                        .map(element -> new SearchResult(element.ownText(),element.baseUri(),element.tagName()))
                        .collect(Collectors.toList());
}

This won't take more time than the solutions of the other answers but doesn't have side effects, is thread safe as well as easy to read and understand.