将Java TreeMap代码迁移到Scala？ [英] Migrating Java TreeMap code to Scala?

问题描述

我正在将我的Java代码库迁移到纯Scala，而且我被关于这一段代码。我有一个IntervalMap的实现，即一个数据结构，让你有效地将范围 [从，到] 映射到值其中设置，删除和获取操作全部 O（log n）（与IntervalTree或SegmentTree略有不同）。

I am migrating my Java code base to pure Scala and I am stuck on this one piece of code. I have an implementation of an IntervalMap i.e. a data structures that let's you efficiently map ranges [from,to] to values where the set, delete and get operations are all O(log n) (slightly different from an IntervalTree or a SegmentTree).

此代码使用Java的 java.util.TreeMaps 在迁移到Scala时，我遇到了两个大问题：

This code uses Java's java.util.TreeMaps and while migrating to Scala, I ran into 2 big issues:

1. Scala没有 mutable.TreeMap - 我决定使用 mutable.TreeSet 来解决它（奇怪的是Scala）有 mutable.TreeSet 但没有 mutable.TreeMap ）用于存储密钥并将值存储在辅助<$ c中$ C> mutable.Map 。这是一个令人不快的黑客，但还有更好的方法吗？

1. Scala has no mutable.TreeMap - I decided to go around it by using mutable.TreeSet (oddly Scala has mutable.TreeSet but no mutable.TreeMap) for storing the keys and storing the values in an auxiliary mutable.Map. This is an unpleasant hack but is there any better way?

下一个问题是Scala的 mutable.TreeSet 没有相当于 java.util.TreeSet 的 ceilingKey ， floorEntry ， pollFirst ， pollLast 这些都是 O（log n） Java中的操作。

Next problem is Scala's mutable.TreeSet has no equivalent of java.util.TreeSet's ceilingKey, floorEntry, pollFirst, pollLast which are all O(log n) operations in Java.

那么，我怎样才能最好地将我的代码迁移到Scala？这些情况下的最佳做法是什么？我真的不想编写自己的树实现。有没有更惯用的Scala编写IntervalMaps的方式，我不知道？或者那里有一些有信誉的图书馆？或者Scala只是简单地使用它的gimped TreeSet和不存在的TreeMaps来吮吸它。当然，我可以在Scala中使用Java的 TreeMap 但这很难看，我失去了所有不错的Scala集合功能，我当时也可以使用Java。

So, how can I best migrate my code to Scala? What are the best practices in these situations? I really do not want to write my own tree implementations. Is there a more idiomatic Scala way of writing IntervalMaps that I am not aware of? Or is there some reputable library out there? Or does Scala just plain suck here with its gimped TreeSet and non-existent TreeMaps. Ofcourse I can just use Java's TreeMap in Scala but that is ugly and I lose all the nice Scala collection features and I might as well use Java then.

这是我目前的Java代码： https://gist.github.com/pathikrit/5574521

Here is my current Java code: https://gist.github.com/pathikrit/5574521

推荐答案

Scala 2.12有 mutable.TreeMap 最后：< a href =https://github.com/scala/scala/pull/4504\"rel =nofollow> https://github.com/scala/scala/pull/4504

Scala 2.12 has mutable.TreeMap finally: https://github.com/scala/scala/pull/4504

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