observer

code/05-factory/product.go

@@ -0,0 +1 @@
+package _5_factory

code/05-factory/product_test.go

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+package _5_factory

code/08-observer/notify_observer.go

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+package _8_observer
+
+import (
+	"fmt"
+)
+
+// Subject 是被观察者
+type Subject struct {
+	observers []Observer
+	state     string
+}
+
+// Register 注册观察者
+func (s *Subject) Register(observer Observer) {
+	s.observers = append(s.observers, observer)
+}
+
+// SetState 设置状态并通知观察者
+func (s *Subject) SetState(state string) {
+	s.state = state
+	s.Notify()
+}
+
+// Notify 通知所有观察者
+func (s *Subject) Notify() {
+	for _, observer := range s.observers {
+		go observer.Update(s.state) // 使用协程避免阻塞
+	}
+}
+
+// Observer 观察者接口
+type Observer interface {
+	Update(string)
+}
+
+// ConcreteObserver1 具体观察者1
+type ConcreteObserver1 struct{}
+
+func (o ConcreteObserver1) Update(state string) {
+	fmt.Printf("ConcreteObserver1 received state: %s\n", state)
+}
+
+// ConcreteObserver2 具体观察者2
+type ConcreteObserver2 struct{}
+
+func (o ConcreteObserver2) Update(state string) {
+	fmt.Printf("ConcreteObserver2 received state: %s\n", state)
+}
+

code/08-observer/notify_observer_test.go

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+package _8_observer
+
+import (
+	"testing"
+	"time"
+)
+
+func TestName(t *testing.T) {
+	subject := Subject{}
+	observer1 := ConcreteObserver1{}
+	observer2 := ConcreteObserver2{}
+
+	subject.Register(observer1) // 注册观察者1
+	subject.Register(observer2) // 注册观察者2
+
+	subject.SetState("new state") // 设置状态并通知观察者
+	time.Sleep(5*time.Second)
+}