是否有任何原因EnumMap和EnumSet不可导航 [英] Is there any reason EnumMap and EnumSet are not Navigable

问题描述

Enum是可比较的，这意味着您可以拥有

Enum is Comparable which means you can have

NavigableSet<AccessMode> modes = new TreeSet<>();
NavigableMap<AccessMode, Object> modeMap = new TreeMap<>();

这些有O（ln N）次访问时间。

These have O(ln N) access times.

枚举集合具有O（1）个访问时间，但不可导航

The Enum collections have O(1) access times, but are not Navigable

NavigableSet<AccessMode> modes = EnumSet.noneOf(AccessMode.class); // doesn't compile
NavigableMap<AccessMode, Object> modeMap = new EnumMap<>(AccessMode.class);  // doesn't compile

我想知道是否有一个原因Enum集合不可导航排序）。即我缺少某些东西？

I was wondering if there was a reason Enum collections were not Navigable (and Sorted). i.e Am I missing something?

推荐答案

我最好的猜测是，导航性不被视为枚举集的主要用例。在实现中没有什么会阻止可导航性。将 TreeSet 和 TreeMap 覆盖了将一组枚举成员的需要与可导航性结合的罕见用例。

My best guess is that navigability was not seen as a major use case for enum sets. There is nothing in the implementation that would prevent navigability. The rare use cases that combine the need for a set of enum members with navigability are covered by the TreeSet and TreeMap.

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