Collections.sort 使用什么设计模式?

When applying a comparator to a list in the following manner, what is the design pattern being used or what is the technique being used here?

Collections.sort(myCollection, new Comparator<MyItem>() {

    @Override
    public int compare(MyItem item1, MyItem item2) {
        return item1.getId().compareTo(item2.getId());
    }

});

推荐答案

TL;DR :

Collections.sort 是一个简单的多态替换示例，无论您是使用函数式编程还是面向对象编程来进行这种替换.策略模式这个术语不能与多态性或函数式编程互换.

Collections.sort is an example of a simple polymorphic substitution regardless of whether you use Functional Programming or Object Oriented Programming to make this substitution. The term Strategy Pattern is not interchangeable with Polymorphism or Functional Programming.

我们仍然可以说我们将排序 Strategy 传递给 sort 方法，但没有 Context，它不等同于策略模式.

One could still say that we are passing a sorting Strategy to the sort method but without the Context, it is not synonymous to the Strategy Pattern.

当以下列方式将比较器应用到列表时，所使用的设计模式或此处使用的技术是什么?

When applying a comparator to a list in the following manner, what is the design pattern being used or what is the technique being used here?

由于此问题已被标记为 OOP，因此此处本身没有使用 OOP design-pattern.这是一个普通的旧多态.一些程序员可能将其称为策略模式，但我不同意.Strategy 模式提倡 Composition 而不是 Inheritiance，您使用 has-a 关系而不是 is-a 关系.

Since this question has been tagged as OOP, there is no OOP design-pattern being used here per-se. This is plain old Polymorphism in action. Some programmers may call this the Strategy Pattern but I disagree. The Strategy pattern advocates Composition over Inheritiance where you use a has-a relationship rather than an is-a relationship.

一些程序员可能会进一步争辩说，我们正在将排序 Strategy 传递给 Collections.sort 方法，所以这就是 Strategy Pattern；然而，需要承认的是，Strategy 是 Strategy Pattern 的组成部分之一.Strategy 模式的另一个重要组成部分是它的 Context，它与 Strategy 建立 HAS-A 关系.这个组件是 Strategy Pattern 背后动机的核心，它更喜欢 composition 而不是 inheritance.你不能从整体中取出一个部分，仍然把那个分离的部分称为一个整体.您不能将 Context 从 Strategy Pattern 中取出，而仍将其余部分称为 Strategy Pattern.

Some programmers may further argue that we are passing a sorting Strategy to the Collections.sort method so this is the Strategy Pattern; however, what one needs to acknowledge is that Strategy is one of the components of the Strategy Pattern. The other important component of the Strategy pattern is its Context that establish a HAS-A relationship with the Strategy. This component is central to the motivation behind the Strategy Pattern which is to prefer composition over inheritance. You can't take a part out of the whole and still call that separated part a whole. You can't take the Context out of the Strategy Pattern and still call the remainder the Strategy Pattern.

Collections.sort 是一个 static 方法，它允许您多态 将 Comparator 实现替换为在运行时使用.

Collections.sort is a static method that is allowing you to Polymorphically substitute the Comparator implementation to be used at runtime.

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