工廠方法模式

工廠方法模式讓一個類的例項化延遲到子類

public class FactoryMethodTest {
    public static void main(String[] args) {
        Application application = new ConcreteProductA();
        //Application application = new ConcreteProductB();
        Product product = application.getObject();
        product.method();
    }
}

interface Product {
    public void method();
}

class ProductA implements Product {

    @Override
    public void method() {
        System.out.println("ProductA 實現的方法");
    }
}

class ProductB implements Product {

    @Override
    public void method() {
        System.out.println("ProductB 實現的方法");
    }
}


abstract class Application {
    //相當於工廠方法
    abstract Product createProduct();
    
    public Product getObject(){
        return createProduct();
    }
}

//子類實現
class ConcreteProductA extends Application {
    @Override
    Product createProduct() {
        return new ProductA();
    }
}

//子類實現
class ConcreteProductB extends Application {
    @Override
    Product createProduct() {
        return new ProductB();
    }
}