10.11 Conclusion 结论

Special cases of any form make code harder to understand and increase the likelihood of bugs. This chapter focused on exceptions, which are one of the most significant sources of special-case code, and discussed how to reduce the number of places where exceptions must be handled. The best way to do this is by redefining semantics to eliminate error conditions. For exceptions that can’t be defined away, you should look for opportunities to mask them at a low level, so their impact is limited, or aggregate several special-case handlers into a single more generic handler. Together, these techniques can have a significant impact on overall system complexity.

任何形式的特殊情况都使代码更难以理解，并增加了发生错误的可能性。本章重点讨论异常，异常是特殊情况代码的最重要来源之一，并讨论了如何减少必须处理异常的地方的数量。做到这一点的最佳方法是重新定义语义以消除错误条件。对于无法定义的异常，您应该寻找机会将它们掩盖到较低的水平，以免影响有限，或者将多个特殊情况的处理程序聚合到一个更通用的处理程序中。总之，这些技术可能会对整体系统复杂性产生重大影响。

1Ding Yuan et. al., “Simple Testing Can Prevent Most Critical Failures: An Analysis of Production Failures in Distributed Data-Intensive Systems,” 2014 USENIX Conference on Operating System Design and Implementation.

1 丁元等 等人，“简单的测试可以防止最关键的故障：对分布式数据密集型系统中的生产故障的分析”，2014 USENIX 操作系统设计和实施大会。