Sleeping barber problem solution without Mutex and lock (http://en.wikipedia.org/wiki/Sleeping_barber_problem)

barber.go

package main

import (
  "time"
)

const (
	BARBERS_AMOUNT   = 1
	HALL_SITS_AMOUNT = 3
)

type Barber struct {
	val int
}

type Client struct {
	val int
}

func clientProducer(clients chan *Client) {
	for {
		time.Sleep(1 * time.Second)
		clients <- &Client{}
	}
}

func cutHear(barber *Barber, client *Client, finished chan *Barber) {
	// Cutting hear 
	finished <- barber
}

func BarberShop(clients <-chan *Client) {
	freeBarbers := []*Barber{}
	waitingClient := []*Client{}
	syncBarberChan := make(chan *Barber)

	//creating barbers
	for i := 0; i < BARBERS_AMOUNT; i++ {
		freeBarbers = append(freeBarbers, &Barber{})
	}

	for {
		select {
		case client := <-clients:
			if len(freeBarbers) == 0 {
				if len(waitingClient) < HALL_SITS_AMOUNT {
					// client is waiting in the hall
					waitingClient = append(waitingClient, client)
				} else {
					// hall is full - bye-bye client
				}
			} else {
				barber := freeBarbers[0]
				freeBarbers = freeBarbers[1:]
				go cutHear(barber, client, syncBarberChan)
			}
		// barber finish work
		case barber := <-syncBarberChan:
			if len(waitingClient) > 0 {
				// get client from hall
				client := waitingClient[0]
				waitingClient = waitingClient[1:]
				go cutHear(barber, client, syncBarberChan)
			} else {
				// barber is going to sleep
				freeBarbers = append(freeBarbers, barber)
			}
		}
	}

}

func main() {

	clients := make(chan *Client)

	go clientProducer(clients)

	go BarberShop(clients)

	time.Sleep(10 * time.Minute)
}