go观察者模式

package main

import "fmt"

func main() {
	sub := NewSubject("东北")
	sub.Register(Observer{
		Uid:  123,
		Name: "张三",
	})
	sub.Register(Observer{
		Uid:  124,
		Name: "李四",
	})

	sub.NotifyAll()
}

// ObserverInterface 观察者
type ObserverInterface interface {
	Notify()
}

// Observer 具体观察者
type Observer struct {
	Uid  int32
	Name string
}

func (o Observer) Notify() {
	fmt.Printf("观察者【%d】：%s \n", o.Uid, o.Name)
}

// SubjectInterface 主体，也就是观察者模式的主体
type SubjectInterface interface {
	Register(o ObserverInterface)
	Deregister(o ObserverInterface)
	NotifyAll()
}

type Subject struct {
	observerMap map[int32]Observer
	name        string
}

func NewSubject(name string) *Subject {
	return &Subject{
		name:        name,
		observerMap: map[int32]Observer{},
	}
}

func (s *Subject) Register(o Observer) {
	if _, ok := s.observerMap[o.Uid]; ok {
		return
	}

	s.observerMap[o.Uid] = o
}

func (s *Subject) Deregister(o Observer) {
	if _, ok := s.observerMap[o.Uid]; !ok {
		return
	}
	delete(s.observerMap, o.Uid)
}

func (s *Subject) NotifyAll() {
	for _, o := range s.observerMap {
		o.Notify()
	}
}