一、Pull Up Field 提取字段
多个类中有相同的字段，可以提取到父类中。
重构前：
public class Engineer
{ public string name { get; set; }
} public class Salesman
{ public string name { get; set; }
}重构后：
public class Employee
{ public string name { get; set; }
} public class Engineer:Employee
{
} public class Salesman : Employee
{
}
二、Pull_Up_Method 提取方法
多个类中有相同或相似的方法时，可以提取到父类
重构前：
class Preferred_Customer
{ void CreateBill(DateTime date)
{ double chargeAmount = ChargeFor();
AddBill(date, chargeAmount);
} void AddBill(DateTime date, double amount)
{
} public double ChargeFor()
{ return 1;
}
} class Regular_Customer
{ void CreateBill(DateTime date)
{ double chargeAmount = ChargeFor();
AddBill(date, chargeAmount);
} void AddBill(DateTime date, double amount)
{
} double ChargeFor()
{ return 2;
}
}重构后：
abstract class Customer
{ void CreateBill(DateTime date)
{ double chargeAmount = ChargeFor();
AddBill(date, chargeAmount);
} void AddBill(DateTime date, double amount)
{
} public abstract double ChargeFor();
} class Preferred_Customer: Customer
{ public override double ChargeFor()
{ return 1;
}
} class Regular_Customer:Customer
{ public override double ChargeFor()
{ return 2;
}
}子类中的ChargeFor方法实现不同，父类中的ChargeFor为抽象方法。子类通过重写实现。
三、Pull_Up_Constructor_Body 提取构造函数
多个类的构造函数代码类似，可以提取到父类中
重构前：
class Manager
{ string _name; int _id; public Manager(string name,int id)
{
_name = name;
_id = id;
Init();
} void Init()
{ object obj1 = new object();
}
} class Manager1
{ string _name; int _id; int _grade; public Manager1(string name,int id,int grade)
{
_name = name;
_id = id;
_grade = grade;
Init();
} void Init()
{ object obj2 = new object();
_grade = 2;
}
}重构后：
abstract class Employee
{ protected string _name; protected int _id; public Employee(string name, int id)
{
_name = name;
_id = id;
Init();
} protected abstract void Init();
} class Manager:Employee
{ public Manager(string name, int id):base(name,id)
{
} protected override void Init()
{ object obj1 = new object();
}
} class Manager1 : Employee
{ int _grade; public Manager1(string name, int id, int grade) : base(name, id)
{
_grade = grade;
} protected override void Init()
{ object obj2 = new object();
_grade = 2;
}
}子类中的构造函数中调用的Init方法实现不同，在父类中做成抽象方法。
四、Extract_Subclass 提炼子类
当一个类中出现根据类型调用不同的方法，或者一个类中有多个职责的时候，我们可以考虑提炼子类
重构前：
class PrintClass
{ string _path; string _jsonData; string _sourceBillFlag;
List<int> _sourceBillId; int _lableType; public PrintClass(string path, string jsonData, string sourceBillFlag, List<int> sourceBillId, int lableType)
{
_path = path;
_jsonData = jsonData;
_sourceBillFlag = sourceBillFlag;
_sourceBillId = sourceBillId;
_lableType = lableType;
} public void Print()
{ switch(_lableType)
{ case 1:
PrintBartender(_path,_jsonData); break; case 2:
PrintCodeSoft(_path, _jsonData); break; case 3:
PrintCloud(_sourceBillFlag,_sourceBillId); break;
}
} void PrintBartender(string path, string jsonData)
{
} void PrintCodeSoft(string path, string jsonDat)
{
} void PrintCloud(string sourceBillFlag, List<int> sourceBillId)
{
}
}View Code
比如这个打印类中，根据类型，调不同的打印方法。
重构后：
namespace Extract_Subclass
{ class PrintBase
{ string _path; string _jsonData; public PrintBase(string path, string jsonData)
{
_path = path;
_jsonData = jsonData;
} public virtual void Print( )
{
}
} class BartenderPrint : PrintBase
{ public BartenderPrint(string path, string jsonData):base(path,jsonData)
{
} public override void Print()
{ //call bartender api }
} class CodeSoftPrint : PrintBase
{ public CodeSoftPrint(string path, string jsonData) : base(path, jsonData)
{
} public override void Print()
{ //call CodeSoft api }
} class CloudPrint:PrintBase
{ string _sourceBillFlag;
List<int> _sourceBillId; public CloudPrint(string sourceBillFlag, List<int> sourceBillId) :base("","")
{
_sourceBillFlag = sourceBillFlag;
_sourceBillId = sourceBillId;
} public override void Print()
{ //Cloud print }
}
}View Code
五、Extract Superclass 提炼父类
几个类的字段，方法，构造函数等都有部分相同之处，可以提取到父类中。
重构前：
class Department
{ string _name; public Department(string name)
{
_name = name;
} public string GetName()
{ return _name;
} public int GetTotalaAnnualCost()
{ int result = 0;
GetStaff().ForEach(p=>
{
result += p.GetAnnualCost();
}); return result;
} private List GetStaff()
{ return default(List);
}
}View Code
class Employee
{ string _name; string _id; int _annualCost; public Employee(string name,string id,int annualCost)
{
_name = name;
_id = id;
_annualCost = annualCost;
} public string GetName()
{ return _name;
} public int GetAnnualCost()
{ return _annualCost;
}
}View Code
Department类中有个GetTotalaAnnualCost方法，获取总费用，Employee中有个GetAnnualCost方法，获取费用。我们可以提取到父类中，修改成相同的名称。
重构后：
namespace RefactoringDome.Extract_Superclass
{ abstract class Part
{ string _name; public Part(string name)
{
_name = name;
} public string GetName()
{ return _name;
} public abstract int GetAnnualCost();
}
}namespace RefactoringDome.Extract_Superclass.Dome
{ class Employee : Part
{ string _id; int _annualCost; public Employee(string name, string id, int annualCost) : base(name)
{
_id = id;
_annualCost = annualCost;
} public override int GetAnnualCost()
{ return _annualCost;
}
} class Department:Part
{
public Department(string name):base(name)
{
} public override int GetAnnualCost()
{ int result = 0;
GetStaff().ForEach(p =>
{
result += p.GetAnnualCost();
}); return result;
} private List GetStaff()
{ return default(List);
}
}
}View Code
六、Form Template Method 模板方法
两个方法中的流程大致相同，我们可以提炼成模板方法。
重构前：
class Customer
{ public string Statement()
{
List<string> details = GetDetails(); string result = "Rental Record for" + GetName() + "\n";
details.ForEach(p=>
{
result += "Details is" + p + "\n";
});
result += "Total Charge:"+GetTotalCharge(); return result;
} public string HtmlStatement()
{
List<string> details = GetDetails(); string result = "Rental Record for" + GetName() + "\n";
details.ForEach(p =>
{
result += "Details is" + p + "\n";
});
result += "Total Charge:" + GetTotalCharge()+""; return result;
} public List<string> GetDetails()
{ return default(List<string>);
} public string GetName()
{ return "";
} public decimal GetTotalCharge()
{ return 0;
}
}Customer类中有两个打印小票的方法，一个是winform调的，一个是Html调的。方法中代码结构一样，只是部分显示字符串不同。
这种很符合提取成模板函数。
重构后：
namespace RefactoringDome.Form_Template_Method
{ abstract class Statement
{ public string Value(Customer customer)
{
List<string> details = customer.GetDetails(); string result = HeaderString(customer);
details.ForEach(p =>
{
result += DetailString(p);
});
result += FooterString(customer); return result;
} protected abstract string HeaderString(Customer customer); protected abstract string DetailString(string detailInfo); protected abstract string FooterString(Customer customer);
} class TextStatement : Statement
{ protected override string HeaderString(Customer customer)
{ return "Rental Record for" + customer.GetName() + "\n";
} protected override string DetailString(string detailInfo)
{ return "Details is" + detailInfo + "\n";
} protected override string FooterString(Customer customer)
{ return "Total Charge:" + customer.GetTotalCharge();
}
} class HtmlStatement : Statement
{ protected override string HeaderString(Customer customer)
{ return "Rental Record for" + customer.GetName() + "\n";
} protected override string DetailString(string detailInfo)
{ return "Details is" + detailInfo + "\n";
} protected override string FooterString(Customer customer)
{ return "Total Charge:" + customer.GetTotalCharge() + "";
}
}
}
把不同的部分，用抽象函数代替。子类中去重写实现具体实现。
七、Replace Inheritance with Delegation 继承替换为委托
子类只用了父类一小部分方法。这种情况可以考虑将继承替换为委托。
重构前：
class List
{ public object FirstElement()
{ return default(object);
} public void Insert(object element)
{
} public void Remove(object element)
{
} public int FindIndex(object obj)
{ return 0;
} public void Sort()
{
}
} class Queue: List
{ public void Push(object element)
{
Insert(element);
} public void Pop()
{ object obj = FirstElement();
Remove(obj);
}
}Queue类继承了List类，使用了List类的Insert、Remove、FirstElement方法。但是List类中还有Sort、FindIndex方法在子类中没有用到。这样父类传达给调用端的信息并不是你想要体现的。这种情况我们应该使用List的委托。
重构后：
class Queue
{
List _list = new List(); public void Push(object element)
{
_list.Insert(element);
} public void Pop()
{ object obj = _list.FirstElement();
_list.Remove(obj);
}
}八、Replace Delegation with inheritance 委托替换为继承
一个类中，引用了另一个类的实例，但是当前类中的方法，委托类里都有，这种情况应该用继承替换委托。
重构前：
class Employee
{
Person _person = new Person(); public string GetName()
{ return _person.GetName();
} public void SetName(string name)
{
_person.SetName(name);
} public new string ToString()
{ return "my name is:"+_person.GetLastName();
}
} class Person
{ string _name;
public string GetName()
{ return _name;
} public void SetName(string name)
{
_name = name;
} public string GetLastName()
{ return _name.Substring(1);
}
}
重构后：
class Employee:Person
{ public new string ToString()
{ return "my name is:" + GetLastName();
}
}代码结构清晰简洁了不少。
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