go 的单例

main.go

import (
    "singleton"
)

func main() {
    mSingleton, nSingleton := singleton.NewSingleton("hello"), singleton.NewSingleton("hi")
    mSingleton.SaySomething()
    nSingleton.SaySomething()
  
    c := make(chan int)
    go newObject("hello", c)
    go newObject("hi", c)

    <-c
    <-c
 }

 func newObject(str string, c chan int) {
     nSingleton := singleton.NewSingleton(str)
     nSingleton.SaySomething()
     c <- 1
 }
 

singleton.go

package singleton

import (
    "fmt"
)

type Singleton interface {
    SaySomething()
}

type singleton struct {
    text string
}

var oneSingleton Singleton

func NewSingleton(text string) Singleton {
    if oneSingleton == nil {
        oneSingleton = &singleton{
            text: text,
        }
    }
    return oneSingleton
}

func (this *singleton) SaySomething() {
    fmt.Println(this.text)
}