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Java中的多个继承中的接口，建模问题

[英]interfaces in multiple inheritance in java, modelling issue

原文 2013-08-19 00:40:07 8 3 java/ interface/ multiple-inheritance

I have the following scenario: 我有以下情况：

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As you can see, I have two classes that are Lecturers and Students. 如您所见，我有两个班级，分别是讲师和学生。 The class Teacher Assistants are a mix between Lectures and Students, that is because they can enrolled into courses, but they can also lecture some basic topics (without being considered Lecturers). 班级助教是讲课和学生之间的混合体，这是因为他们可以报名参加课程，但他们也可以讲一些基本主题（不被视为讲师）。 I came with the idea to model this situation using Interfaces because I will program in in Java. 我想到了使用接口对这种情况建模的想法，因为我将使用Java进行编程。 Is this modelling correct? 这个模型正确吗？

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So that the TA class will implement the Interface Teaches, which contains an array of the courses assigned to this student to teach. 这样TA班将实现接口教学，其中包含分配给该学生教书的一系列课程。

But if I model in that way I realize that I am loosing the class Lecturers at all. 但是，如果我以这种方式建模，我就会意识到自己完全失去了全班讲师。 How I can model this situation of multiple inheritance, but not loosing the class Lecturers? 我如何才能为这种多重继承的情况建模，但又不失去全班讲师的职责？ I mean if I program Lecturers as an interface it would not have any methods that I would need further, for example, calculus of its wage benefits and so on. 我的意思是，如果我将讲师编程为接口，它将没有任何我需要进一步使用的方法，例如，计算其工资福利等。 Any recommendation? 有什么建议吗？

3 个解决方案

You can make Lecturer into an interface, then have both TeachingAssistant and Professor implement it. 您可以将Lecturer为一个界面，然后由TeachingAssistant和Professor实施。 TeachingAssistant can extend Student , because from a logical point of view, teaching assistants are students. TeachingAssistant可以扩展Student ，因为从逻辑的角度来看，助教是学生。

One option is to have Teacher and Teachable interfaces and then have Lecturer implement Teacher (for want of a word like Teacherable!), Student implement Teachable and TA implement both Teacher and Teachable . 一种选择是拥有Teacher和Teachable接口，然后让Lecturer实现Teacher （需要像Teacherable这样的单词）， Student实现Teachable而TA实现Teacher和Teachable 。

Lecturer , Student and TA could all extend Faculty_Staff . Lecturer ， Student和TA均可扩展Faculty_Staff 。

tbodt's approach , in my opinion, is generally sound. 我认为， tbodt的做法总体上是合理的。 You just have to ask: if some client code needs a Lecturer , would an instance of a TA suffice? 您只需要问：如果某些客户端代码需要Lecturer ，TA实例就足够了吗？ If there's an issue with that, you can choose to design it with composition, abstracting the ability to teach into a separate class of its own, something like TeachingJob (I can't think of a better name). 如果存在问题，您可以选择按构图设计，将其教学能力抽象为一个单独的类，例如“ TeachingJob （我想不出更好的名字）。 This way the only thing that actual Professor s and TeachingAssistant s share is that they have similar teaching jobs; 这样，实际的Professor和TeachingAssistant共享的唯一东西就是他们具有相似的教学工作。 they do not belong to the same "class" (interface actually). 它们不属于同一“类”（实际上是接口）。

Hybrid approach would be to involve TeachingJob with the Lecturer interface, eg Lecturer would have a assign(TeachingJob assignment) method. 混合的方法是涉及TeachingJob与Lecturer接口，例如Lecturer将有一个assign(TeachingJob assignment)方法。