chore: menambahkan contoh penerapan channel

Author: agungfir98

intermediate/concurrency/goroutines/contoh_channel.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"sync"
+	"time"
+)
+
+type Order struct {
+	Id     int
+	status string
+}
+
+func generateOrder(n int) []*Order {
+	orders := []*Order{}
+
+	for i := range n {
+		order := Order{
+			Id:     i + 1,
+			status: "pending",
+		}
+		orders = append(orders, &order)
+	}
+
+	return orders
+}
+
+func processOrder(orderChan <-chan *Order, wg *sync.WaitGroup) {
+	defer wg.Done()
+	// loop berikut menerima value dari channel terus menerus hingga ditutup.
+	for order := range orderChan {
+		time.Sleep(time.Duration(rand.Intn(500)+10) * time.Millisecond)
+		status := []string{"delivered", "shipped"}[rand.Intn(2)]
+		order.status = status
+		fmt.Printf("procssing order: %d with status: %s\n", order.Id, order.status)
+	}
+}
+
+func main() {
+	var wg sync.WaitGroup
+	wg.Add(2)
+
+	n := 20
+	orderChan := make(chan *Order, n)
+
+	go func() {
+		wg.Done()
+		for _, order := range generateOrder(n) {
+			orderChan <- order
+		}
+		// karena kita mengirim data ke channel pada function ini, maka kita dapat panggil fungsi close di sini
+		close(orderChan)
+		fmt.Printf("done generating order\n")
+	}()
+
+	go processOrder(orderChan, &wg)
+
+	wg.Wait()
+	fmt.Printf("All operation is done!\n")
+}