go-pattern-examples/behavior/10_observer/obserser.go
2020-04-21 22:53:23 +08:00

48 lines
681 B
Go

package observer
import "fmt"
type Subject struct {
observers []Observer
context string
}
func NewSubject() *Subject {
return &Subject{
observers: make([]Observer, 0),
}
}
func (s *Subject) Attach(o Observer) {
s.observers = append(s.observers, o)
}
func (s *Subject) notify() {
for _, o := range s.observers {
o.Update(s)
}
}
func (s *Subject) UpdateContext(context string) {
s.context = context
s.notify()
}
type Observer interface {
Update(*Subject)
}
type Reader struct {
name string
}
func NewReader(name string) *Reader {
return &Reader{
name: name,
}
}
func (r *Reader) Update(s *Subject) {
fmt.Printf("%s receive %s\n", r.name, s.context)
}