移动方法

概念：本文所讲的移动方法就是方法放在合适的位置（通常指放在合适的类中）。

正文：移动方法是一个很简单也很常见的重构，只要是系统就会存在很多类，那么类里面包括很多方法，如果一个方法经常被另外一个类使用（比本身的类使用还多）或者这个方法本身就不应该放在这个类里面，那么这个适合应该考虑把它移到合适的类中。代码如下：

namespace LosTechies.DaysOfRefactoring.MoveMethod.Before
{
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 double CalculateInterestRate()
{
if (CreditScore > 800)
return 0.02;            if (AccountAge > 10)
return 0.03;            return 0.05;
}
}    public class AccountInterest
{
public BankAccount Account { get; private set; }        public AccountInterest(BankAccount account)
{
Account = account;
}        public double InterestRate
{
get { return Account.CalculateInterestRate(); }
}        public bool IntroductoryRate
{
get { return Account.CalculateInterestRate() < 0.05; }
}
}
}

移动以后大家可以看到BankAccount类的职责也单一，同时CalculateInterestRate也放到了经常使用且适合它的类中了，所以此重构是一个比较好的重构，能让整个代码变得更加合理。

namespace LosTechies.DaysOfRefactoring.MoveMethod.After
{
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;
}
}
}

namespace LosTechies.DaysOfRefactoring.MoveMethod.After
{
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; }
}
}

总结：这个重构法则在很多时候能让我们把代码组织的结构调整得更合理，同时也能给以后的维护带来方便。