• 步步为营 .NET 代码重构学习笔记 六

    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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  • 原文地址：https://www.cnblogs.com/Leo_wl/p/2057785.html
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