为什么Guava的ImmutableList有这么多重载的（）方法？ [英] Why does Guava's ImmutableList have so many overloaded of() methods?

问题描述

我只是看着Guava的 ImmutableList 我注意到（）方法的重载了12次。

I was just looking at Guava's ImmutableList and I noticed that the of() method was overloaded 12 times.

在我看来他们所需要的只是：

It looks to me that all they needed was:

static <E> ImmutableList<E> of();
static <E> ImmutableList<E> of(E element); // not even necessary
static <E> ImmutableList<E> of(E... elements);

有这么多类似变化的原因是什么？

What's the reason for having so many similar variations?

推荐答案

Varargs和泛型不能很好地融合在一起。 Varargs方法可能会导致带有泛型参数的警告，并且重载会阻止该警告，除非在极少数情况下您希望使用 of（）。

Varargs and generics do not play nicely together. Varargs methods can cause a warning with generic arguments, and the overloads prevent that warning except in the rare case that you want to add more than 11 items to the immutable list using of().

来源中的评论说：

这些是十一。在那之后，你只需要获得varargs表格，以及随之而来的任何警告。 :(

These go up to eleven. After that, you just get the varargs form, and whatever warnings might come along with it. :(

请注意Java 7的 @ SafeVarargs 注释专门添加，以消除对此类事物的需求。单个（E ... ）可以使用带有 @SafeVarargs 注释的方法，并且不会给出带有通用参数的警告。

Note that Java 7's @SafeVarargs annotation was added specifically to eliminate the need for this sort of thing. A single of(E...) method annotated with @SafeVarargs could be used and would not give warnings with generic arguments.

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