java - 如何将函数重构为目标函数？

Question

鲍勃叔叔在他的“干净代码”中提供了无需步骤的重构示例，因此我在阅读时尝试复制它们。

原始代码:

public int calculateWeeklyPay(boolean overtime) {
 int tenthRate = getTenthRate();
 int tenthsWorked = getTenthsWorked();
 int straightTime = Math.min(400, tenthsWorked);
 int overTime = Math.max(0, tenthsWorked - straightTime);
 int straightPay = straightTime * tenthRate;
 double overtimeRate = overtime ? 1.5 : 1.0 * tenthRate;
 int overtimePay = (int)Math.round(overTime*overtimeRate);
 return straightPay + overtimePay;
 }

重构:

public int straightPay() {
 return getTenthsWorked() * getTenthRate();
 }
 public int overTimePay() {
 int overTimeTenths = Math.max(0, getTenthsWorked() - 400);
 int overTimePay = overTimeBonus(overTimeTenths);
 return straightPay() + overTimePay;
 }
 private int overTimeBonus(int overTimeTenths) {
 double bonus = 0.5 * getTenthRate() * overTimeTenths;
 return (int) Math.round(bonus);
 }

问题出在加类费上。当我尝试替换变量和函数时，我得到以下结果:

overtimePay = round(max(0, tenthsWorked - min(400, tenthsWorked))*tenthRate);

在原始和目标中

overtimePay = round(0.5 * tenthRate * max(0, tenthsWorked - 400));

为什么是 0.5？

另外，原来的overtimeRate中可能少了一个“)”，但是不管怎样，为什么新的overtimePay是这样的呢？

Answer 1

0.5 * tenthRate来自加类率 ( 1.5 * tenthRate ) 和非加类率 ( 1.0 * tenthRate ) 之间的差异。

重构版本背后的逻辑是，您不必为非加类时间和加类时间单独计算工资金额，而只需为整个工作时间支付标准费率