大話設計模式_簡單原廠模式

本文用原廠模式實現 計算機的四則運算

package com.wzs.design;import java.util.Scanner;/** * 大話設計模式--page10 簡單原廠模式 *  * @author Administrator *  */public class SimpleFactory {public static void main(String[] args) {System.out.println("請輸入數字和操作符:(1-加法，2-減法，3-乘法，4-除法)");Scanner input = new Scanner(System.in);double numA = input.nextDouble();double numB = input.nextDouble();int operationNum = input.nextInt();Operation operation = OperationFactory.createOperation(operationNum);operation.setNumA(numA);operation.setNumB(numB);System.out.println(operation.getResult());}}/** * 產生操作的簡單工廠 */class OperationFactory {public static Operation createOperation(int operationNum) {Operation operation = null;switch (operationNum) {case 1:operation = new OperationAdd();break;case 2:operation = new OperationSub();break;case 3:operation = new OperationMul();break;case 4:operation = new OperationDiv();break;default:break;}return operation;}}/** * 操作運算 */class Operation {public double numA;public double numB;public void setNumA(double numA) {this.numA = numA;}public void setNumB(double numB) {this.numB = numB;}public double getResult() {double result = 0;return result;}}/** * 加 + */class OperationAdd extends Operation {@Overridepublic double getResult() {double result = super.numA + super.numB;return result;}}/** * 減 + */class OperationSub extends Operation {@Overridepublic double getResult() {double result = super.numA - super.numB;return result;}}/** * 乘 * */class OperationMul extends Operation {@Overridepublic double getResult() {double result = super.numA * super.numB;return result;}}/** * 除 / */class OperationDiv extends Operation {@Overridepublic double getResult() {if (super.numB == 0) {System.out.println("除數不能為0.");System.exit(0);}double result = super.numA / super.numB;return result;}}