大話設計模式讀書筆記系列-1.簡單工廠模式(靜態工廠模式)

>>>大話設計模式讀書筆記系列目錄>>>

簡單工廠模式(靜態工廠模式)

簡單設計模式不符合開放-封閉原則,若是新增一種運算須要涉及改動的類過多。

 

場景：採用簡單工廠模式設計一款運算器能夠自由添加運算規則

 

 

 

計算器運算抽象類

 1 /**
 2  * 計算器運算抽象類
 3  */
 4 public abstract class Operation {
 5     /**
 6      * 操做數A
 7      */
 8     private double numberA;
 9     /**
10      * 操做數B
11      */
12     private double numberB;
13 
14     /**
15      * 抽象方法
16      * 得到操做結果
17      *
18      * @return
19      */
20     public abstract double getResult();
21 
22     /**
23      * 獲取 操做數A
24      *
25      * @return numberA 操做數A
26      */
27     public double getNumberA() {
28         return this.numberA;
29     }
30 
31     /**
32      * 設置 操做數A
33      *
34      * @param numberA 操做數A
35      */
36     public void setNumberA(double numberA) {
37         this.numberA = numberA;
38     }
39 
40     /**
41      * 獲取 操做數B
42      *
43      * @return numberB 操做數B
44      */
45     public double getNumberB() {
46         return this.numberB;
47     }
48 
49     /**
50      * 設置 操做數B
51      *
52      * @param numberB 操做數B
53      */
54     public void setNumberB(double numberB) {
55         this.numberB = numberB;
56     }
57 
58     @Override
59     public String toString() {
60         return "Operation{" +
61                 "numberA=" + numberA +
62                 ", numberB=" + numberB +
63                 '}';
64     }
65 }

 

運算器子類

 1 /**
 2  * 加法運算類
 3  */
 4 public class OperationAdd extends Operation {
 5 
 6     @Override
 7     public double getResult() {
 8         return super.getNumberA() + super.getNumberB();
 9     }
10 }
11 
12 /**
13  * 減法運算類
14  */
15 public class OperationSub extends Operation {
16     @Override
17     public double getResult() {
18         return super.getNumberA() - super.getNumberB();
19     }
20 }
21 
22 /**
23  * 乘法運算類
24  */
25 public class OperationMul extends Operation {
26     @Override
27     public double getResult() {
28         return super.getNumberA() * super.getNumberB();
29     }
30 }
31 
32 /**
33  * 除法運算類
34  */
35 public class OperationDiv extends Operation {
36     @Override
37     public double getResult() {
38         return super.getNumberA() / super.getNumberB();
39     }
40 }

運算靜態工廠類

 1 /**
 2  * 運算靜態工廠類
 3  */
 4 public class OperationFactory {
 5     /**
 6      * 建立運算工廠
 7      * @param operate 操做符(+ - * /)
 8      * @return 匹配運算類
 9      */
10     public static  Operation createOperation(String operate)
11     {
12         Operation operation=null;
13         switch (operate)
14         {
15             case "+":
16                 operation=new OperationAdd();//建立加法運算類
17                 break;
18             case "-":
19                 operation=new OperationSub();//建立減法運算類
20                 break;
21             case "*":
22                 operation=new OperationMul();//建立乘法運算類
23                 break;
24             case "/":
25                 operation=new OperationDiv();//建立除法運算類
26                 break;
27         }
28         return operation;
29     }
30 }

 

調用端

/**
 * 大話設計模式(java版)
 * 第一章:簡單工廠模式(靜態工廠模式)
 */
public class StaticFactoryMethodDemo {

    public static void main(String[] args) {
        Operation operation = null;
        double result = 0;
        operation = OperationFactory.createOperation("+");
        operation.setNumberA(1.1);
        operation.setNumberB(2.2);
        result = operation.getResult();
        System.out.println("加法結果".concat(String.valueOf(result)));

        operation = OperationFactory.createOperation("-");
        operation.setNumberA(3.3);
        operation.setNumberB(2.2);
        result = operation.getResult();
        System.out.println("減法結果".concat(String.valueOf(result)));

        operation = OperationFactory.createOperation("*");
        operation.setNumberA(3.3);
        operation.setNumberB(2.2);
        result = operation.getResult();
        System.out.println("乘法結果".concat(String.valueOf(result)));

        operation = OperationFactory.createOperation("/");
        operation.setNumberA(3.3);
        operation.setNumberB(2.2);
        result = operation.getResult();
        System.out.println("除法結果".concat(String.valueOf(result)));

    }
}

 

結果

加法結果3.3000000000000003
減法結果1.0999999999999996
乘法結果7.26
除法結果1.4999999999999998