Simple Factory / 简单工厂

基础结构

type Human interface {
    SayHello()
}
type Man struct {
}
func (m *Man) SayHello() {
    fmt.Println("Hello,I am a man ")
}
type Woman struct {
}
func (w *Woman) SayHello() {
    fmt.Println("Hello,I am a woman")
}

simpleFactory.go

// 简单工厂
type SimpleFactory struct {
    cache map[string]CreateFunc // 缓存实例的创建方式
}
type CreateFunc func() Human
var (
    instance *SimpleFactory // 工厂单例
    once     sync.Once      // 用来保证instance只会被初始化一次
)
// 获取工厂实例
func New() *SimpleFactory {
    once.Do(func() {
        instance = &SimpleFactory{
            cache: map[string]CreateFunc{
                "man": func() Human {
                    return &Man{}
                },
                "woman": func() Human {
                    return &Woman{}
                },
            },
        }
    })
    return instance
}
// 获取实例
func (s *SimpleFactory) Get(key string) (Human, bool) {
    if v, ok := s.cache[key]; ok {
        return v(), true
    }
    return nil, false
}

main.go

package main
import (
    "simpleFactory"
    "fmt"
)
func main() {
    if man, ok := simpleFactory.New().Get("man"); ok {
        man.SayHello()
    }
    if woman, ok := simpleFactory.New().Get("woman"); ok {
        woman.SayHello()
    }
    if child, ok := simpleFactory.New().Get("child"); ok {
        child.SayHello()
    }
}