步步为营 .NET 代码重构学习笔记 七
一、Extract Class（提炼类）
动机（Motivation）
一个class应该是一个清楚的抽象（abstract），处理一些明确的责任。但在实际工作中，class会不断成长扩展。这个class会变得过份复杂，很快，class就会变成一团乱麻。
示例
public class Person
{
private string _name;
private string _officeAreaCode;
private string _officeNumber;
public string Name
{
get { return _name; }
set { _name = value; }
}
public string OfficeAreaCode
{
get { return _officeAreaCode; }
set { _officeAreaCode = value; }
}
public string OfficeNumber
{
get { return _officeNumber; }
set { _officeNumber = value; }
}
public string TelephoneNumber
{
get { return "(" + _officeAreaCode + ")" + _officeNumber; }
}
}
改为
public class Person
{
private string _name;
private Telephone _telephoneNumber;
public Telephone TelephoneNumber
{
get { return _telephoneNumber; }
set { _telephoneNumber = value; }
}
public string Name
{
get { return _name; }
set { _name = value; }
}
public string TemphoneNumber
{
get { return _telephoneNumber.TelephoneNumber; }
}
}
public class Telephone
{
private string _officeAreaCode;
private string _officeNumber;
public string OfficeAreaCode
{
get { return _officeAreaCode; }
set { _officeAreaCode = value; }
}
public string OfficeNumber
{
get { return _officeNumber; }
set { _officeNumber = value; }
}
public string TelephoneNumber
{
get { return "(" + _officeAreaCode + ")" + _officeNumber; }
}
}
二、Inline Class（将类内联化）
动机（Motivation）
一个class不再承担足够责任、不再有单独存在的理由，将class的所有特性搬移到另一个class中，然后移除原class。
示例
public class User
{
private int _ID;
private string _name;
public int ID
{
get { return _ID; }
set { _ID = value; }
}
public string Name
{
get { return _name; }
set { _name = value; }
}
}
public class UserInfo
{
private int _ID;
private string _Age;
public string ID
{
get { return _ID; }
set { _ID = value; }
}
public string Age
{
get { return _Age; }
set { _Age = value; }
}
}
改为
public class User
{
private int _ID;
private string _name;
private string _Age;
public int ID
{
get { return _ID; }
set { _ID = value; }
}
public string Name
{
get { return _name; }
set { _name = value; }
}
public string Age
{
get { return _Age; }
set { _Age = value; }
}
}
三、Hide Delegate（隐藏[委托关系]）
动机（Motivation）
[封装]即使不是对象的最关键特征，也是最关键特征之一。[封装]意味每个对象都应该尽可能少了解系统的其它部分。如此一来，一旦发生变化，需要了解这变化的对象就会比较少，这会使谈化比较容易进行。
示例
public class User
{
private int _ID;
private string _name;
private Department _depart;
public int ID
{
get { return _ID; }
set { _ID = value; }
}
public string Name
{
get { return _name; }
set { _name = value; }
}
public Department Depart
{
get { return _depart; }
set { _depart = value; }
}
}
public class Department
{
private string _departName;
private User _manager;
public string DepartName
{
get { return _departName; }
set { _departName = value; }
}
public User Manager
{
get { return _manager; }
set { _manager = value; }
}
}
改为
public class User
{
private int _ID;
private string _name;
private Department _depart;
public int ID
{
get { return _ID; }
set { _ID = value; }
}
public string Name
{
get { return _name; }
set { _name = value; }
}
public Department Depart
{
get { return _depart; }
set { _depart = value; }
}
public string DepartmentManager
{
get { return _depart.Manager; }
}
}
public class Department
{
private string _departName;
private User _manager;
public string DepartName
{
get { return _departName; }
set { _departName = value; }
}
public User Manager
{
get { return _manager; }
set { _manager = value; }
}
}
这样取部门管理者就更直接，更方便，适合于少量使用。
但如果有大量的方法都用到了DepartmentManager里，我们就要去掉中间人了。
四、Remove Middle Man（移除中间人）
动机（Motivation）
大量重复的代码是万恶之源。这些重复性代码应该抽出来放进同一个函数中。
示例
public class User
{
private int _ID;
private string _name;
private Department _depart;
public int ID
{
get { return _ID; }
set { _ID = value; }
}
public string Name
{
get { return _name; }
set { _name = value; }
}
public Department Depart
{
get { return _depart; }
set { _depart = value; }
}
public string DepartmentManager
{
get { return _depart.Manager; }
}
}
public class Department
{
private string _departName;
private User _manager;
public string DepartName
{
get { return _departName; }
set { _departName = value; }
}
public User Manager
{
get { return _manager; }
set { _manager = value; }
}
}
改为
public class User
{
private int _ID;
private string _name;
private Department _depart;
public int ID
{
get { return _ID; }
set { _ID = value; }
}
public string Name
{
get { return _name; }
set { _name = value; }
}
public Department Depart
{
get { return _depart; }
set { _depart = value; }
}
}
public class Department
{
private string _departName;
private User _manager;
public string DepartName
{
get { return _departName; }
set { _departName = value; }
}
public User Manager
{
get { return _manager; }
set { _manager = value; }
}
}
在调用时就直接Depart.Manager来取得它的值.