之前有看过《ruby设计模式》,不过渐渐的都忘记了。现在买了一个大话设计模式,看起来不是那么枯燥,顺便将代码用ruby实现了一下。
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
|
# -*- encoding: utf-8 -*- #运算类 class Operation attr_accessor :number_a , :number_b def initialize(number_a = nil , number_b = nil ) @number_a = number_a @number_b = number_b end def result 0 end end #加法类 class OperationAdd < Operation def result number_a + number_b end end #减法类 class OperationSub < Operation def result number_a - number_b end end #乘法类 class OperationMul < Operation def result number_a * number_b end end #除法类 class OperationDiv < Operation def result raise '除数不能为0' if number_b == 0 number_a / number_b end end #工厂类 class OperationFactory def self .create_operate(operate) case operate when '+' OperationAdd. new () when '-' OperationSub. new () when '*' OperationMul. new () when '/' OperationDiv. new () end end end oper = OperationFactory.create_operate( '/' ) oper.number_a = 1 oper.number_b = 2 p oper.result |
这样写的好处是降低耦合。
比如增加一个开根号运算的时候,只需要在工厂类中添加一个分支,并新建一个开根号类,不会去动到其他的类。
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
# -*- encoding: utf-8 -*- #运算类 class Operation attr_accessor :number_a , :number_b def initialize(number_a = nil , number_b = nil ) @number_a = number_a @number_b = number_b end def result 0 end end #加法类 class OperationAdd < Operation def result number_a + number_b end end #减法类 class OperationSub < Operation def result number_a - number_b end end #乘法类 class OperationMul < Operation def result number_a * number_b end end #除法类 class OperationDiv < Operation def result raise '除数不能为0' if number_b == 0 number_a / number_b end end module FactoryModule def create_operation end end #加法工厂 class AddFactory include FactoryModule def create_operation OperationAdd. new end end #减法工厂 class SubFactory include FactoryModule def create_operation OperationSub. new end end #乘法工厂 class MulFactory include FactoryModule def create_operation OperationMul. new end end #除法工厂 class DivFactory include FactoryModule def create_operation OperationDiv. new end end factory = AddFactory. new oper = factory.create_operation oper.number_a = 1 oper.number_b = 2 p oper.result |
相比于简单工厂模式,这里的变化是移除了工厂类,取而代之的是具体的运算工厂,分别是加法工厂、减法工厂、乘法工厂和除法工厂。