为什么Guava类提供了如此多的工厂方法而不是只提供varargs的方法？ [英] Why do Guava classes provide so many factory methods instead of just one that takes varargs?

问题描述

可能重复：

为什么Guava的ImmutableList有这么多重载的（）方法？

查看Guava的 ImmutableList （以及其他一些类），你会发现很多重载的便利方法（退货一个包含给定元素的不可变列表，按顺序。）使用不同数量的参数：

Looking at Guava's ImmutableList (and some other classes), you'll find plenty of overloaded of convenience methods ("Returns an immutable list containing the given elements, in order.") that take a different number of parameters:

...
public static <E> ImmutableList<E> of(E e1, E e2, E e3) 
public static <E> ImmutableList<E> of(E e1, E e2, E e3, E e4) 
public static <E> ImmutableList<E> of(E e1, E e2, E e3, E e4, E e5) 
... 

一直到这个：

public static <E> ImmutableList<E> of(E e1,
                                      E e2,
                                      E e3,
                                      E e4,
                                      E e5,
                                      E e6,
                                      E e7,
                                      E e8,
                                      E e9,
                                      E e10,
                                      E e11,
                                      E e12,
                                      E... others) 

我的一些同事认为这很愚蠢，想知道为什么不只有一种方法： of（E ..元素）。他们怀疑这是一个不良导向的表现优化，属于你认为你比编译器更聪明，或类似的东西。

Some colleagues of mine consider this silly, wondering why there's isn't just one method: of(E... elements). They suspect it's an ill-guided performance "optimisation" that falls into the category "do you think you're smarter than compiler", or something like that.

我的预感就是Kevin Bourrillion等人。把这些方法放在那里是出于真正的原因。任何人都可以解释（或推测）这个原因是什么吗？

My hunch is that Kevin Bourrillion et al. put these methods in there for a real reason. Can anyone explain (or speculate) what that reason might be?

推荐答案

来源说：

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

所以，这是因为varargs方法产生带有泛型参数的警告。

So, this was done because varargs methods produce a warning with generic arguments.

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