Java 8流-将方法传递给过滤器 [英] Java 8 streams - passing a method to a filter

问题描述

我有一组整数set2和一个对象:

I have a set of integers set2 and an object:

public class Bucket {
    private Integer id;
    private Set<Integer> set1;
...
}

我想使用流过滤存储桶，但是仅使用set1与另一个set2相交的存储桶.我尝试了以下代码:

I want to filter Buckets using streams, but only buckets where their set1 has intersection with another set2. I tried the following code:

Set<Bucket> selectedBuckets = allBuckets.stream()
    .filter(e -> Sets.intersection(e.getSet1(), set2).size()>1)
    .collect(Collectors.toSet());

但是这将返回allBuckets的所有元素，而不是仅返回包含交集的元素.我怎样才能做到这一点 ?

But this would return all elements of allBuckets, instead of only the elements whose sets contains the intersection. How can I do this ?

推荐答案

假设与List中的任何Bucket交叉(Set set1内容)是您要寻找的内容:

What you might just be looking for assuming you meant intersection(of Set set1 content) with any other Bucket in the List :

List<Bucket> allBuckets = new ArrayList<>(); // as you may initialise
Set<Bucket> selectedBuckets = allBuckets.stream()
        .filter(e -> allBuckets.stream()
                .filter(f -> f != e)
                .flatMap(b -> b.getSet1().stream())
                .anyMatch(s -> e.getSet1().contains(s)))
        .collect(Collectors.toSet());

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