第 8 章 降低复杂性

Chapter 8 Pull Complexity Downwards

This chapter introduces another way of thinking about how to create deeper classes. Suppose that you are developing a new module, and you discover a piece of unavoidable complexity. Which is better: should you let users of the module deal with the complexity, or should you handle the complexity internally within the module? If the complexity is related to the functionality provided by the module, then the second answer is usually the right one. Most modules have more users than developers, so it is better for the developers to suffer than the users. As a module developer, you should strive to make life as easy as possible for the users of your module, even if that means extra work for you. Another way of expressing this idea is that it is more important for a module to have a simple interface than a simple implementation.

本章介绍了有关如何创建更深层类的另一种思考方式。假设您正在开发一个新模块，并且发现了一个不可避免的复杂性。哪个更好：应该让模块用户处理复杂性，还是应该在模块内部处理复杂性？如果复杂度与模块提供的功能有关，则第二个答案通常是正确的答案。大多数模块拥有的用户多于开发人员，因此开发人员遭受的苦难要大于用户。作为模块开发人员，您应该努力使模块用户的生活尽可能轻松，即使这对您来说意味着额外的工作。表达此想法的另一种方法是，模块具有简单的接口比简单的实现更为重要。

As a developer, it’s tempting to behave in the opposite fashion: solve the easy problems and punt the hard ones to someone else. If a condition arises that you’re not certain how to deal with, the easiest thing is to throw an exception and let the caller handle it. If you are not certain what policy to implement, you can define a few configuration parameters to control the policy and leave it up to the system administrator to figure out the best values for them.

作为开发人员，很容易以相反的方式行事：解决简单的问题，然后将困难的问题推给其他人。如果出现不确定如何处理的条件，最简单的方法是引发异常并让调用方处理它。如果不确定要实施什么策略，则可以定义一些配置参数来控制该策略，然后由系统管理员自行确定最佳策略。

Approaches like these will make your life easier in the short term, but they amplify complexity, so that many people must deal with a problem, rather than just one person. For example, if a class throws an exception, every caller of the class will have to deal with it. If a class exports configuration parameters, every system administrator in every installation will have to learn how to set them.

这样的方法短期内会使您的生活更轻松，但它们会加剧复杂性，因此许多人必须处理一个问题，而不仅仅是一个人。例如，如果一个类抛出异常，则该类的每个调用者都必须处理该异常。如果一个类导出配置参数，则每个安装中的每个系统管理员都必须学习如何设置它们。