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

01
public class Person 

02
{ 

03
    private string _name; 

04
    private string _officeAreaCode; 

05
    private string _officeNumber; 

06
 
07
    public string Name 

08
    { 

09
        get { return _name; } 

10
        set { _name = value; } 

11
    } 

12
 
13
    public string OfficeAreaCode 

14
    { 

15
        get { return _officeAreaCode; } 

16
        set { _officeAreaCode = value; } 

17
    } 

18
 
19
    public string OfficeNumber 

20
    { 

21
        get { return _officeNumber; } 

22
        set { _officeNumber = value; } 

23
    } 

24
 
25
    public string TelephoneNumber 

26
    { 

27
        get { return "(" + _officeAreaCode + ")" + _officeNumber; } 

28
    } 

29
}

改为

01
public class Person 

02
  { 

03
      private string _name; 

04
      private Telephone _telephoneNumber; 

05
 
06
      public Telephone TelephoneNumber 

07
      { 

08
          get { return _telephoneNumber; } 

09
          set { _telephoneNumber = value; } 

10
      } 

11
 
12
      public string Name 

13
      { 

14
          get { return _name; } 

15
          set { _name = value; } 

16
      } 

17
 
18
      public string TemphoneNumber 

19
      { 

20
          get { return _telephoneNumber.TelephoneNumber; } 

21
      } 

22
 
23
  } 

24
  public class Telephone 

25
  { 

26
      private string _officeAreaCode; 

27
      private string _officeNumber; 

28
      public string OfficeAreaCode 

29
      { 

30
          get { return _officeAreaCode; } 

31
          set { _officeAreaCode = value; } 

32
      } 

33
 
34
      public string OfficeNumber 

35
      { 

36
          get { return _officeNumber; } 

37
          set { _officeNumber = value; } 

38
      } 

39
 
40
      public string TelephoneNumber 

41
      { 

42
          get { return "(" + _officeAreaCode + ")" + _officeNumber; } 

43
      } 

44
  }

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

01
public class User 

02
{ 

03
    private int _ID; 

04
    private string _name; 

05
 
06
    public int ID 

07
    { 

08
        get { return _ID; } 

09
        set { _ID = value; } 

10
    } 

11
 
12
    public string Name 

13
    { 

14
        get { return _name; } 

15
        set { _name = value; } 

16
    } 

17
 
18
 
19
} 

20
public class UserInfo 

21
{ 

22
    private int _ID; 

23
    private string _Age; 

24
 
25
    public string ID 

26
    { 

27
        get { return _ID; } 

28
        set { _ID = value; } 

29
    } 

30
 
31
    public string Age 

32
    { 

33
        get { return _Age; } 

34
        set { _Age = value; } 

35
    } 

36
}

改为

01
public class User 

02
{ 

03
    private int _ID; 

04
    private string _name; 

05
    private string _Age; 

06
 
07
    public int ID 

08
    { 

09
        get { return _ID; } 

10
        set { _ID = value; } 

11
    } 

12
 
13
    public string Name 

14
    { 

15
        get { return _name; } 

16
        set { _name = value; } 

17
    } 

18
 
19
    public string Age 

20
    { 

21
        get { return _Age; } 

22
        set { _Age = value; } 

23
    } 

24
}

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

01
public class User 

02
{ 

03
    private int _ID; 

04
    private string _name; 

05
    private Department _depart; 

06
 
07
    public int ID 

08
    { 

09
        get { return _ID; } 

10
        set { _ID = value; } 

11
    } 

12
 
13
    public string Name 

14
    { 

15
        get { return _name; } 

16
        set { _name = value; } 

17
    } 

18
 
19
    public Department Depart 

20
    { 

21
        get { return _depart; } 

22
        set { _depart = value; } 

23
    } 

24
 
25
} 

26
 
27
public class Department 

28
{ 

29
    private string _departName; 

30
    private User _manager; 

31
 
32
    public string DepartName 

33
    { 

34
        get { return _departName; } 

35
        set { _departName = value; } 

36
    } 

37
 
38
    public User Manager 

39
    { 

40
        get { return _manager; } 

41
        set { _manager = value; } 

42
    } 

43
}

改为

01
public class User 

02
  { 

03
      private int _ID; 

04
      private string _name; 

05
      private Department _depart; 

06
 
07
      public int ID 

08
      { 

09
          get { return _ID; } 

10
          set { _ID = value; } 

11
      } 

12
 
13
      public string Name 

14
      { 

15
          get { return _name; } 

16
          set { _name = value; } 

17
      } 

18
 
19
      public Department Depart 

20
      { 

21
          get { return _depart; } 

22
          set { _depart = value; } 

23
      } 

24
 
25
      public string DepartmentManager 

26
      { 

27
          get { return _depart.Manager; } 

28
      } 

29
  } 

30
 
31
  public class Department 

32
  { 

33
      private string _departName; 

34
      private User _manager; 

35
 
36
      public string DepartName 

37
      { 

38
          get { return _departName; } 

39
          set { _departName = value; } 

40
      } 

41
 
42
      public User Manager 

43
      { 

44
          get { return _manager; } 

45
          set { _manager = value; } 

46
      } 

47
  }

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

01
public class User 

02
{ 

03
    private int _ID; 

04
    private string _name; 

05
    private Department _depart; 

06
 
07
    public int ID 

08
    { 

09
        get { return _ID; } 

10
        set { _ID = value; } 

11
    } 

12
 
13
    public string Name 

14
    { 

15
        get { return _name; } 

16
        set { _name = value; } 

17
    } 

18
 
19
    public Department Depart 

20
    { 

21
        get { return _depart; } 

22
        set { _depart = value; } 

23
    } 

24
 
25
    public string DepartmentManager 

26
    { 

27
        get { return _depart.Manager; } 

28
    } 

29
} 

30
 
31
public class Department 

32
{ 

33
    private string _departName; 

34
    private User _manager; 

35
 
36
    public string DepartName 

37
    { 

38
        get { return _departName; } 

39
        set { _departName = value; } 

40
    } 

41
 
42
    public User Manager 

43
    { 

44
        get { return _manager; } 

45
        set { _manager = value; } 

46
    } 

47
}

改为

01
public class User 

02
{ 

03
    private int _ID; 

04
    private string _name; 

05
    private Department _depart; 

06
 
07
    public int ID 

08
    { 

09
        get { return _ID; } 

10
        set { _ID = value; } 

11
    } 

12
 
13
    public string Name 

14
    { 

15
        get { return _name; } 

16
        set { _name = value; } 

17
    } 

18
 
19
    public Department Depart 

20
    { 

21
        get { return _depart; } 

22
        set { _depart = value; } 

23
    } 

24
 
25
} 

26
 
27
public class Department 

28
{ 

29
    private string _departName; 

30
    private User _manager; 

31
 
32
    public string DepartName 

33
    { 

34
        get { return _departName; } 

35
        set { _departName = value; } 

36
    } 

37
 
38
    public User Manager 

39
    { 

40
        get { return _manager; } 

41
        set { _manager = value; } 

42
    } 

43
}

在调用时就直接Depart.Manager来取得它的值.

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步步为营 .NET 代码重构学习笔记 七

步步为营 .NET 代码重构学习笔记七