简单工厂模式的UML类图与源码实现

原文：http://hlzhou.iteye.com/blog/551492

源码：Operation类

 package Operation;

 public abstract class Operation {
     double numberA=0;
     double numberB=0;

     public double getNumberA() {
         return numberA;
     }

     public void setNumberA(double numberA) {
         this.numberA = numberA;
     }

     public double getNumberB() {
         return numberB;
     }

     public void setNumberB(double numberB) {
         this.numberB = numberB;
     }

     public abstract double operate();
 }

 加类：

 package Operation;

 public class Add extends Operation {

     @Override
     public double operate() {
         return numberA+numberB;
     }
 }

 减类：

 package Operation;

 public class Sub extends Operation {

     @Override
     public double operate() {
         return numberA-numberB;
     }
 }

 乘类：

 package Operation;

 public class Mul extends Operation {

     @Override
     public double operate() {
         return numberA*numberB;
     }
 }

 除类：

 package Operation;

 import java.io.IOError;

 public class Div extends Operation {

     @Override
     public double operate() {
         try {
             return numberA/numberB;
         } catch (IOError e) {
             System.out.println("除数不能为空！");
             return 0;
         }
     }
 }

 

工厂类:

 import Operation.Add;
 import Operation.Div;
 import Operation.Mul;
 import Operation.Operation;
 import Operation.Sub;

 public class OperationFactory {
     public static Operation createOperation(char operate){
         Operation operation=null;
         switch (operate) {
         case '+':
             operation=new Add();
             break;
         case '-':
             operation=new Sub();
             break;
         case '*':
             operation=new Mul();
             break;
         case '/':
             operation=new Div();
             break;
         }
         return operation;
     }
 }

 客户端：

 import Operation.Operation;
 public class Client {

     public static void main(String[] args) {
         Operation operation = OperationFactory.createOperation('*');
         operation.setNumberA(12);
         operation.setNumberB(6);
         System.out.println(operation.operate());
     }
 }