设计模式（2）-------------简单工厂模式（代码实现）

Posted on 2010-05-20 10:26 java小爬虫阅读(1873) 评论(1) 编辑收藏

/**
*简单工厂模式其实不是23种设计模式之一，但是它是创建型模式的最基础的内容，
*工厂方法和抽象工厂都是在它的基础上的改良版。
*关于简单工厂模式的优缺点，请看设计模式（1）------工厂类设计模式。
*
*
*它是对对象实例化的过程和需要实例化的对象进行细节上的封装。
*
* 优点：工厂类中包含了必要的逻辑判断，根据客户端的选择条件动态实例化相关类。对于客户端来说，去除了与具体产品的依赖。

*缺点：当需要增加产生一个新对象实例的方法时，需要修改工厂类，这样，工厂类就违背了“开-闭原则”。
  *
*/

  1package simpleFactroy;
  2
  3public class Operation  {
  4    private double dNumberA;
  5    private double dNumberB;
  6
  7    public double getResults(){
  8        return 0l ;
  9    }
10
11    public double getdNumberA() {
12        return dNumberA;
13    }
14
15    public void setdNumberA(double dNumberA) {
16        this.dNumberA = dNumberA;
17    }
18
19    public double getdNumberB() {
20        return dNumberB;
21    }
22
23    public void setdNumberB(double dNumberB) {
24        this.dNumberB = dNumberB;
25    }
26
27    public Operation(double dNumberA, double dNumberB) {
28        this.dNumberA = dNumberA;
29        this.dNumberB = dNumberB;
30    }
31
32    public Operation(double dNumberA) {
33        this.dNumberA = dNumberA;
34    }
35
36    public Operation() {
37
38    }
39
40
41}
42
43
44package simpleFactroy;
45
46public class OperationAdd extends Operation {
47    public double getResults() {
48        return  getdNumberA() + getdNumberB() ;
49    }
50}
51
52
53package simpleFactroy;
54
55public class OperationSub extends Operation {
56
57    public double getResults() {
58        return  getdNumberA() - getdNumberB() ;
59    }
60
61}
62
63
64
65package simpleFactroy;
66
67public class OperationSqrt extends Operation {
68
69    @Override
70    public double getResults() {
71        return Math.sqrt(getdNumberA());
72    }
73
74
75}
76
77
78
79package simpleFactroy;
80
81public class OperationFactroy {
82    public static Operation getOperation(String opr){
83        Operation operation = null ;
84        if(opr.equals("+")){
85            operation = new OperationAdd();
86        }else if(opr.equals("-")){
87            operation = new OperationSub();
88        }else{
89            operation = new OperationSqrt();
90        }
91        return operation ;
92    }
93
94}
95
96
97
98package simpleFactroy;
99
100import java.util.Scanner;
101
102
103public class TestCalculate {
104    public static void main(String[] args)throws Exception{
105        while (true) {
106            Scanner src = new Scanner(System.in);
107            double a = src.nextDouble();
108            String operation = src.next();
109            double b = src.nextDouble();
110            System.out.println(calculate(a, operation, b));
111            System.out.println(calculate(a));
112        }
113    }
114
115    public static double calculate(double a,String operation, double b ){
116        Operation opr = OperationFactroy.getOperation(operation);
117        opr.setdNumberA(a);
118        opr.setdNumberB(b);
119        return opr.getResults();
120    }
121    public static double calculate(double a){
122        Operation opr = OperationFactroy.getOperation("");
123        opr.setdNumberA(a);
124        return opr.getResults();
125    }
126
127}
128