In this case we do not define an instance variable in the injectee, but an abstract method returning the required object. The method may be public or protected

在这个例子中，我们没有在被注入者中定义一个实例变量，而是定义了一个返回所需对象的抽象方法。

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I found it seems useful to separate abstract method into two methods, one for public interface, the other to be overridden by subclasses.

我发现似乎有用的抽象方法分离到两个方法，一个公共接口，另一个是被子类覆盖。

youdao

Abstract: the audience survey is the empirical study and quantitative analytical method developed on the base of the public opinion poll and market research in the western countries.

对事物进行系统周密的考察和了解：要了解情况，唯一的方法是向社会作调查，调查社会各阶级的生动情况。

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