31天重构指南之二：移动方法

1: public class BankAccount

2: {

3:     public BankAccount(int accountAge, int creditScore, AccountInterest accountInterest)

4:     {

5:         AccountAge = accountAge;

6:         CreditScore = creditScore;

7:         AccountInterest = accountInterest;

8:     }

9: 

10:     public int AccountAge { get; private set; }

11:     public int CreditScore { get; private set; }

12:     public AccountInterest AccountInterest { get; private set; }

13: 

14:     public double CalculateInterestRate()

15:     {

16:         if (CreditScore > 800)

17:             return 0.02;

18: 

19:         if (AccountAge > 10)

20:             return 0.03;

21: 

22:         return 0.05;

23:     }

24: }

25: 

26: public class AccountInterest

27: {

28:     public BankAccount Account { get; private set; }

29: 

30:     public AccountInterest(BankAccount account)

31:     {

32:         Account = account;

33:     }

34: 

35:     public double InterestRate

36:     {

37:         get { return Account.CalculateInterestRate(); }

38:     }

39: 

40:     public bool IntroductoryRate

41:     {

42:         get { return Account.CalculateInterestRate() < 0.05; }

43:     }

44: }

上面代码中让我们感兴趣的是BankAccount.CalculateInterest方法，我们需要对它进行重构，重构的提示是我们需要将方法定义在对它使用最多的类中。在这个例子中，我们要将

BankAccount.CalculateInterest方法移动到AccountInterest类中。重构后的代码如下：

1: public class BankAccount

2: {

3:     public BankAccount(int accountAge, int creditScore, AccountInterest accountInterest)

4:     {

5:         AccountAge = accountAge;

6:         CreditScore = creditScore;

7:         AccountInterest = accountInterest;

8:     }

9: 

10:     public int AccountAge { get; private set; }

11:     public int CreditScore { get; private set; }

12:     public AccountInterest AccountInterest { get; private set; }

13: }

14: 

15: public class AccountInterest

16: {

17:     public BankAccount Account { get; private set; }

18: 

19:     public AccountInterest(BankAccount account)

20:     {

21:         Account = account;

22:     }

23: 

24:     public double InterestRate

25:     {

26:         get { return CalculateInterestRate(); }

27:     }

28: 

29:     public bool IntroductoryRate

30:     {

31:         get { return CalculateInterestRate() < 0.05; }

32:     }

33: 

34:     public double CalculateInterestRate()

35:     {

36:         if (Account.CreditScore > 800)

37:             return 0.02;

38: 

39:         if (Account.AccountAge > 10)

40:             return 0.03;

41: 

42:         return 0.05;

43:     }

44: }