设计模式(1)-----简单工厂模式

简单工厂模式

package com.csdhsm.designpattem.simplefactory;

/**
* <p>All rights Reserved, Designed By Han</p>
* @Title:  Operator.java
* @Package com.csdhsm.designpattem.simplefactory
* @Description: 运算抽象类，提供抽象方法
* @author: Han
* @E-mail: 294098789@qq.com
* @date:   2016年6月16日 上午10:48:44
* @version:V1.0
*/
public abstract class Operator {

protected double num1 = 0;
protected double num2 = 0;

public void setNum1(double num1) {
this.num1 = num1;
}

public void setNum2(double num2) {
this.num2 = num2;
}

//抽象方法
abstract public double calculate();
}

package com.csdhsm.designpattem.simplefactory;

/**
* <p>All rights Reserved, Designed By Han</p>
* <p>For Taoyuan Web Application</p>
* @Title:  FourOperations.java
* @Package com.csdhsm.designpattem.simplefactory
* @Description: TODO
* @author: Han
* @E-mail: 294098789@qq.com
* @date:   2016年6月16日 上午10:50:09
* @version:V1.0
*/
class OperationAdd extends Operator {

@Override
public double calculate() {
return num1 + num2;
}
}

class OperationSub extends Operator {

@Override
public double calculate() {
return num1 - num2;
}
}

class OperationMul extends Operator {

@Override
public double calculate() {
return num1 * num2;
}
}

class OperationDiv extends Operator {

@Override
public double calculate() {
if(num2 == 0)
throw new RuntimeException("除数不能为0!");
return num1 / num2;
}
}

package com.csdhsm.designpattem.simplefactory;

/**
* <p> All rights Reserved, Designed By Han</p>
* @Title: Factory.java
* @Package com.csdhsm.designpattem.simplefactory
* @Description: 工厂类
* @author: Han
* @E-mail: 294098789@qq.com
* @date: 2016年6月16日 上午10:33:48
* @version:V1.0
*/
public class Factory {

private static Operator operator;

public static Operator getOperator(String type) {

if (type == null) {
throw new NullPointerException();
}

//根据运算符号获得对应的计算类(对字符串switch/case判断，只有jdk1.7以上版本)
switch (type) {
case "+":
operator = new OperationAdd();
break;
case "-":
operator = new OperationSub();
break;
case "*":
operator = new OperationMul();
break;
case "/":
operator = new OperationDiv();
break;
default:
throw new RuntimeException("未能识别的符号!");
}

return operator;
}
}

package com.csdhsm.designpattem.simplefactory;

/**
* <p>All rights Reserved, Designed By Han</p>
* @Title:  Solution.java
* @Package com.csdhsm.designpattem.simplefactory
* @Description: 简单工厂模式
* @author: Han
* @E-mail: 294098789@qq.com
* @date:   2016年6月7日 下午3:44:07
* @version:V1.0
*/
public class Solution {

public static void main(String[] args) {
double num1 = 7;
double num2 = 0;
String type = "*";

Operator operator = Factory.getOperator(type);
operator.setNum1(num1);
operator.setNum2(num2);

System.out.println(operator.calculate());
}
}