[英]Why does Spliterator's getExactSizeIfKnown() NOT call hasCharacteristics()
[英]Why does HashSet return -1 for getExactSizeIfKnown
我试图了解SplitIterator的功能,并遇到以下问题:
public static void main(String[] args) {
Set<Integer> l = new HashSet();
l.add(1);
l.add(2);
l.add(3);
Spliterator<Integer> s= (Spliterator<Integer>) l.spliterator();
Spliterator<Integer> s1=s.trySplit();
while(s1.tryAdvance(n -> {System.out.print(n+" ");System.out.println("estimateSize "+s.estimateSize()+" getexactsizeifknown "+s.getExactSizeIfKnown());}));
为什么getexactsizeifknown
方法为HashSet
返回-1
?
对于其他集合,它返回与estimateSIze()
相同的输出。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.