第2篇 迁移方法

今天的重构同样非常地简单，以至于人们不认为这是一个有价值的重构。迁移方法，顾名思义就是将方法迁移到合适的位置，在开始重构前，我们先看看一下代码：

 

重构前：

public class BankAccount { public BankAccount(int accountAge,int creditScore, AccountInterest accountInterset) { AccountAge = accountAge; CreditScore = creditScore; AccountInterset = accountInterset; } public int AccountAge{get;private set;} public int CreditScore{get;private set;} public AccountInterset AccountInterset {get;private set;} public double CalculateInterestRate() { if(CreditScore>800) return 0.02; if(AccountAge>10) return 0.03; return 0.05; } } public class AccountInterset { public BankAccount Account(get;private set;) public AccountInterset(BankAccount account) { Account = account; } public double InsertRate { get{return Account.CalculateInterset();} } public bool IntroductoryRate { get{return Account.CalculateInterset()<0.05;} } }

这里值得注意的是BankAccount.CalculateInterset方法。当一个方法被其他类使用比在它所在类中的使用还要频繁时，我们就需要使用迁移方法重构了----将方法迁移到更频繁地使用它的类中。由于依赖关系，该重构最终的代码应该是这样的：

 

重构后：

public class BankAccount { public BankAccount(int accountAge,int creditScore,AccountInterest accountInterest) { AccountAge = accountAge; CreditScore = creditScore; AccountInterest = accountInterest; } public int AccountAge {get;private set;} public int CreditScore{get;private set;} public AccountInterest AccountInterest {get;private set;} } public class AccountInterest { public BankAccount Account {get;private set;} public AccountInterest(BankAccount account) { Account = account; } public double InterestRate { get {return CalculateInterestRate();} } public bool IntroductoryRate { get{ return CalculateInterestRate()<0.05;} } public double CalculateInterestRate() { if(Account.CreditScore>800) return 0.02; if(Account.AccountAge>10) return 0.03; return 0.05; } }