Chapter 1:Refactoring,a First Example 重构,第一个例子 The Starting Point 起点 The First Step in Refactoring 重构第一步 Decomposing and Redistributing the Statement Method 分解并重组slalemenl方法 Replacing the Conditional Logic on Price Code with Polymorphism 用多态代替价格条件逻辑代码 Final Thoughts 结语 Chapter 2:Principle