31天重构学习笔记2. 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。
作者：圣殿骑士

补充：综合编程 , 其他综合 ,