UML

classDiagram
    class Product {
<!--more-->
<<interface>>
        +operation()
    }
    class ConcreteProductA {
        +operation()
    }
    class ConcreteProductB {
        +operation()
    }
    class SimpleFactory {
        +createProduct(string) Product
    }
    Product <|.. ConcreteProductA
    Product <|.. ConcreteProductB
    SimpleFactory ..> Product
    SimpleFactory ..> ConcreteProductA
    SimpleFactory ..> ConcreteProductB
````

# Go Sample

package main

import "fmt"

// Product 接口
type Product interface {

Operation() string

}

// ConcreteProductA 结构体
type ConcreteProductA struct{}

func (p *ConcreteProductA) Operation() string {

return "ConcreteProductA"

}

// ConcreteProductB 结构体
type ConcreteProductB struct{}

func (p *ConcreteProductB) Operation() string {

return "ConcreteProductB"

}

// SimpleFactory 结构体
type SimpleFactory struct{}

func (f *SimpleFactory) CreateProduct(productType string) Product {

switch productType {
case "A":
    return &ConcreteProductA{}
case "B":
    return &ConcreteProductB{}
default:
    return nil
}

}

func main() {

factory := &SimpleFactory{}

productA := factory.CreateProduct("A")
fmt.Println(productA.Operation())

productB := factory.CreateProduct("B")
fmt.Println(productB.Operation())

}