设计模式2---工厂模式

为了解决简单工厂模式的缺点，我们通过接口IFactory抽象出工厂类，然后每次增加一个操作类，我就增加工厂类，

从而达到：对扩展开放，对修改关闭。

还是计算器的问题：

UML如下：

 

factory 基类：

public interface IOperatorFactory {
    AbstractOperator CreateOperation();
}

工厂类：

package com.jayfulmath.designpattern.factory;

import com.jayfulmath.designpattern.samplefactory.operator.AbstractOperator;
import com.jayfulmath.designpattern.samplefactory.operator.OperatorAdd;

public class AddFactory implements IOperatorFactory {

    @Override
    public AbstractOperator CreateOperation() {
        // TODO Auto-generated method stub
        return new OperatorAdd();
    }

}

package com.jayfulmath.designpattern.factory;

import com.jayfulmath.designpattern.samplefactory.operator.AbstractOperator;
import com.jayfulmath.designpattern.samplefactory.operator.OperatorPlus;

public class PlusFactory implements IOperatorFactory {

    @Override
    public AbstractOperator CreateOperation() {
        // TODO Auto-generated method stub
        return new OperatorPlus();
    }

}

main：

package com.jayfulmath.designpattern.factory;

import com.jayfulmath.designpattern.main.BasicExample;
import com.jayfulmath.designpattern.samplefactory.operator.AbstractOperator;

public class FactoryMain extends BasicExample {

    @Override
    public void startDemo() {
        // TODO Auto-generated method stub
        IOperatorFactory addFactory = new AddFactory();
        AbstractOperator addOperation = addFactory.CreateOperation();
        addOperation.NumberA = 1;
        addOperation.NumberB = 2;
        System.out.println("[FactoryMain]"+addOperation.NumberA+" add "+addOperation.NumberB+" = "+addOperation.GetResult());    
    }

}

工厂接口生成操作基类。