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Java 11中的CharSequence接口添加了方法`compare`。为什么不比较可比接口的`compareTo`？

[英]CharSequence interface in Java 11 added method `compare`. Why not `compareTo` of Comparable interface?

原文 2019-05-24 21:14:00 8 1 java/ compare/ string-comparison/ comparable/ charsequence

The CharSequence interface gained a new static method in Java 11: compare . CharSequence接口在Java 11中获得了一个新的静态方法： compare 。

This method returns an int : 此方法返回一个int ：

the value 0 if the two CharSequence are equal; 如果两个CharSequence相等，则值为0; a negative integer if the first CharSequence is lexicographically less than the second; 如果第一个CharSequence按字典顺序小于第二个，则为负整数; or a positive integer if the first CharSequence is lexicographically greater than the second. 如果第一个CharSequence按字典顺序大于第二个，则为正整数。

That sounds just like compareTo of Comparable . 这听起来就像compareTo的Comparable 。 Yet the Java team obviously chose to not make CharSequence extend Comparable . 然而，Java团队显然选择不让 CharSequence扩展Comparable 。 Why not? 为什么不？ The logic escapes me. 逻辑逃脱了我。

➥ What is it about CharSequence::compare that would not be an appropriate fit for Comparable::compareTo ? ➥有什么关于CharSequence::compare不适合Comparable::compareTo ？

1 个解决方案

Adding Comparable<CharSequence> wouldn't really work since String implements CharSequence and Comparable<String> . 添加Comparable<CharSequence>不会真正起作用，因为String实现了CharSequence和Comparable<String> 。

For discussion, see this post by one of the OpenJDK developers regarding the subject. 有关讨论，请参阅OpenJDK开发人员之一关于该主题的这篇文章。

Tip from that post: A method reference of the form CharSequence::compare would be suitable as a Comparator . 从该帖子提示： CharSequence::compare形式的方法引用适合作为Comparator 。