工厂方法模式(Factory Method)

工厂方法模式(Factory Method)，定义一个用于创建对象的接口，让子类决定实例化哪一个类。工厂方法使一个类的实例化延迟到其子类。

主方法

/**
 * Created by king on 2017/7/8.
 */
public class main {
    public static void main(String[] args) {
        IFactory operFactory = new AddFactory();
        Operation oper = operFactory.CreateOperation();
        oper.setNumberA(4);
        oper.setNumberB(6);
        double result = oper.getResult();
        System.out.println(result);
    }
}

工厂接口类

public interface IFactory {
    Operation CreateOperation();
}

接口实现类

public class AddFactory implements IFactory {

    public Operation CreateOperation() {
        return new OperationAdd();
    }
}

public class DivFactory implements IFactory {
    public Operation CreateOperation() {
        return new OperationDiv();
    }
}

public class MulFactory implements IFactory {
    public Operation CreateOperation() {
        return new OperationMul();
    }
}

public class SubFactory implements IFactory {
    public Operation CreateOperation() {
        return new OperationSub();
    }
}

Operation相关见《简单工厂模式》