类继承/组合的设计 [英] design of class inheritance/compostion

问题描述

我有两个类：一个读者和一个作家。对于这两个类我有一个抽象接口，因为数据源/目标应该是灵活的：

I do have two classes: a reader and a writer. For both classes I have an abstract interface since the data source/target should be flexible:

class abstract_reader {
...
};

class concrete_reader : public abstract_reader {
   DATATYPE m_data;
...
};    
class abstract_writer {
...
};

class concrete_writer : public abstract_writer {
   DATATYPE m_data;
...
};

作家应具有两个功能，读取和写入concrete_writer的阅读部分的实施是与实现的concrete_reader相同。什么是这些类结合起来的好办法？

The writer shall have both functionalities, to read and to write The implementation of the reading part of the concrete_writer is the same as the implementation of the concrete_reader. What would be a good way to combine these classes?

推荐答案

你想要的是一个有点混乱，但有一些方式：

What you want is a little confusing, but there is a number of ways:

• 从两个抽象类


• 导出作家保持一个指向具体的读者作家


• 保持混凝土读者的一个实例作家


• 从作家取下阅读功能，使第三类，可以读取和写。

• Derive the writer from both abstract classes
• Hold a pointer to the concrete reader in the writer
• Hold an instance of the concrete reader in the writer
• Remove the reading functionality from the writer and make a third class that can both read and write.

就个人而言，我会按照过去的方式，那么你将有一个完整的组类用于读取只，只写，和做这两个。

Personally, I would follow the last way, then you will have a full set of classes for reading-only, writing-only, and for doing both.

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