toy concurrency problem implemented in go

.gitignore

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+*.6
+dinnerparty

Makefile

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+include $(GOROOT)/src/Make.inc
+
+TARG=dinnerparty
+GOFILES=dining-philosophers.go
+
+include $(GOROOT)/src/Make.cmd

dining-philosophers.go

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+/**
+* Toy Go implementation of Dining Philosophers problem
+* http://en.wikipedia.org/wiki/Dining_philosophers_problem
+* Author: Doug Fritz
+* Date: 2011-01-05
+**/
+
+package main
+
+import (
+	"fmt"
+	"rand"
+	"time"
+)
+
+type Philosopher struct {
+	id           int
+	name         string
+	chopstick    chan bool
+	neighbor     *Philosopher
+}
+
+func makePhilosopher(id int, name string, neighbor *Philosopher) *Philosopher {
+	phil := &Philosopher{id, name, make(chan bool, 1), neighbor}
+	phil.chopstick <- true
+	return phil
+}
+
+func (phil *Philosopher) think() {
+	fmt.Printf("%v is thinking.\n",phil.name)
+	time.Sleep(rand.Int63n(1e9))
+}
+
+func (phil *Philosopher) eat() {
+	fmt.Printf("%v is eating.\n", phil.name)
+	time.Sleep(rand.Int63n(1e9))
+}
+
+func (phil *Philosopher) getChopsticks() {
+	timeout := make(chan bool, 1)
+	go func() { time.Sleep(1e9); timeout <- true }()
+	select {
+		case <-phil.chopstick:
+			fmt.Printf("%v got his chopstick.\n",phil.name)
+			select {
+				case <-phil.neighbor.chopstick:
+					fmt.Printf("%v got %v's chopstick.\n",phil.name,phil.neighbor.name)
+					fmt.Printf("%v has two chopsticks.\n",phil.name)
+					return
+				case <-timeout:
+					phil.chopstick <- true
+					phil.think()
+					phil.getChopsticks()
+			}
+		case <-timeout:
+			phil.think()
+			phil.getChopsticks()
+	}
+}
+
+func (phil *Philosopher) returnChopsticks() {
+	phil.chopstick <- true
+	phil.neighbor.chopstick <- true
+}
+
+func (phil *Philosopher) dine(announce chan *Philosopher) {
+	phil.think()
+	phil.getChopsticks()
+	phil.eat()
+	phil.returnChopsticks()
+	announce <- phil
+}
+
+func main() {
+	names := []string{"Kant","Heidegger","Wittgenstein",
+		"Locke","Descartes","Newton","Hume","Leibniz"}
+	philosophers := make([]*Philosopher,len(names))
+	var phil *Philosopher
+	for i, name := range names {
+		phil = makePhilosopher(i,name,phil)
+		philosophers[i] = phil
+	}
+	philosophers[0].neighbor = phil
+	fmt.Printf("There are %v philosophers sitting at a table.\n", len(philosophers))
+	fmt.Println("They each have one chopstick, and must borrow from their neighbor to eat.")
+	announce := make(chan *Philosopher)
+	for _, phil := range philosophers {
+		go phil.dine(announce)
+	}
+	for i :=0; i<len(names); i++ {
+		phil := <-announce
+		fmt.Printf("%v is done dining.\n",phil.name)
+	}
+}