一、Duplicate Observed Data（复制[被监视数据]）
动机（Motivation）
将该笔数据拷贝到一个domain object中。建立一个Observer模式，用以对domain object 和GUI object内的重复数据进行同步控制（sync）。
示例
步步为营 .NET 设计模式学习笔记 十二、Observer (观察者模式)
二、Change Unidirectional Association to Bidirectional（将单向关联改为双向）
动机（Motivation）
添加一个反指针，并使修改函数（modifiers）能够同时更新两条连接。
示例
01 |
public class Order
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{ |
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private Customer _customer;
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04 |
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public Customer NewCustomer
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{
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get { return _customer; }
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set { _customer = value; }
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}
|
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} |
11 |
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public class Customer
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{ |
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} |
改为
01 |
public class Order
|
02 |
{
|
03 |
public List<Customer> CustomerList = new List<Customer>();
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04 |
05 |
public void AddCustomer(Customer arg)
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{
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arg.orderlist.Add(this);
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CustomerList.Add(arg);
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}
|
10 |
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public void RemoveCustomer(Customer arg)
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{
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arg.orderlist.Remove(this);
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CustomerList.Remove(arg);
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}
|
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}
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17 |
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public class Customer
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{
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public List<Order> orderlist = new List<Order>();
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public void AddOrder(Order arg)
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{
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arg.CustomerList.Add(this);
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orderlist.Add(arg);
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}
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public void RemoveOrder(Order arg)
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{
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arg.CustomerList.Remove(this);
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orderlist.Remove(arg);
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}
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}
|
三、Change Bidirectional Association to Unidirectional（将双向改为单向）
动机（Motivation）
两个classes之间有双向关联，但其中一个class如今不再需要另一个class的特性。
示例
01 |
public class Order
|
02 |
{
|
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public List<Customer> CustomerList = new List<Customer>();
|
04 |
05 |
public void AddCustomer(Customer arg)
|
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{
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arg.orderlist.Add(this);
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CustomerList.Add(arg);
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}
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10 |
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public void RemoveCustomer(Customer arg)
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{
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arg.orderlist.Remove(this);
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CustomerList.Remove(arg);
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}
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}
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17 |
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public class Customer
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{
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public List<Order> orderlist = new List<Order>();
|
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public void AddOrder(Order arg)
|
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{
|
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arg.CustomerList.Add(this);
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orderlist.Add(arg);
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}
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public void RemoveOrder(Order arg)
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{
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arg.CustomerList.Remove(this);
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orderlist.Remove(arg);
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}
|
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}
|
改为
01 |
public class Order
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02 |
{ |
03 |
private Customer _customer;
|
04 |
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public Customer NewCustomer
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{
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get { return _customer; }
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set { _customer = value; }
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}
|
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} |
11 |
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public class Customer
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{ |
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} |
四、Replace Magic Number with Symbolic Constant（以符号常量/字面常量取侙魔法数）
动机（Motivation）
创造一个常量，根据其意义为它命名，并将上述的字面数值替换为这个常量。
示例
1 |
public double PotentialEnergy(double mass, double height)
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2 |
{ |
3 |
return mass * 9.51 * height;
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} |
改为
1 |
private double GRAVITATIONAL_CONSTANT = 9.51;
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public double PotentialEnergy(double mass, double height)
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{ |
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return mass * GRAVITATIONAL_CONSTANT * height;
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} |
五、Encapsulate Field（封装值域）
动机（Motivation）
将它声明为private，并提供相应的访问函数（accessors）
示例
1 |
public string _name;
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改为
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private string _name;
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2 |
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public string Name
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{ |
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get { return _name; }
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set { _name = value; }
|
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} |
六、Replace Type Code with Class（以类取代型别码）
动机（Motivation）
以一个新的class替换该数值型别码（type code）
示例
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public class Person
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{ |
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public int O = 0;
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public int A = 1;
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public int B = 2;
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public int AB = 3;
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private int _bloodGroup;
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09 |
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public Person(int bloodGroup)
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{
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_bloodGroup = bloodGroup;
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}
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public int NewBloodGroup
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{
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get { return _bloodGroup; }
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set { _bloodGroup = value; }
|
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}
|
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} |
改为
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public class Person
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{
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public int O = BloodGroup.O.Code;
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public int A = BloodGroup.A.Code;
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public int B = BloodGroup.B.Code;
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public int AB = BloodGroup.AB.Code;
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08 |
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private int _bloodGroup;
|
10 |
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public Person(int bloodGroup)
|
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{
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_bloodGroup = bloodGroup;
|
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}
|
15 |
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public int NewBloodGroup
|
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{
|
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get { return _bloodGroup; }
|
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set { _bloodGroup = value; }
|
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}
|
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}
|
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public class BloodGroup
|
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{
|
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public static BloodGroup O = new BloodGroup(0);
|
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public static BloodGroup A = new BloodGroup(1);
|
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public static BloodGroup B = new BloodGroup(2);
|
28 |
public static BloodGroup AB = new BloodGroup(3);
|
29 |
30 |
private int _code;
|
31 |
32 |
private BloodGroup(int code)
|
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{
|
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_code = code;
|
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}
|
36 |
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public int Code
|
38 |
{
|
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get { return _code; }
|
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set { _code = value; }
|
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}
|
42 |
43 |
}
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