Javaデザパタ本 マルチスレッド編のsection5。 ProducerConsumerパターン

section5.go

package main

import "math/rand"
import "time"
import "fmt"
import "strconv"

// Data役
type Cake struct {
  Id string
}

// Channel役 goだとそのまんまですね...
type Table chan *Cake

func (self *Table) Put(cake *Cake) {
  fmt.Println("put "+cake.Id)
  (*self) <- cake
}

func (self *Table) Take() *Cake{
  cake := <-(*self)
  fmt.Println("take "+cake.Id)
  return cake
}

// Producer役
type CakeMaker struct {
  Name string
  Count int
  Table Table
  RandSeed int64
}

func (self *CakeMaker) Start() {
  source := rand.NewSource(self.RandSeed)
  random := rand.New(source)
  for {
    time.Sleep(time.Millisecond*time.Duration(random.Intn(1000)))
    id := "[ Cake No."+strconv.Itoa(self.NextId())+" by "+self.Name+"]"
    self.Table.Put(&Cake{id})
  }
}

func (self *CakeMaker) NextId() int {
  count := self.Count
  self.Count += 1
  return count
}

// Consumer役
type Eater struct {
  Name string
  Table Table
  RandSeed int64
}

func (self *Eater) Start() {
  source := rand.NewSource(self.RandSeed)
  random := rand.New(source)
  for {
    var _ = self.Table.Take()
    time.Sleep(time.Millisecond*time.Duration(random.Intn(1000)))
  }
}

func main() {
  table := make(Table, 3)
  maker1 := &CakeMaker{"CakeMaker-1", 0, table, 31415}
  maker2 := &CakeMaker{"CakeMaker-2", 0, table, 92653}
  maker3 := &CakeMaker{"CakeMaker-3", 0, table, 32384}
  eater1 := &Eater{"Eater-1", table, 58979}
  eater2 := &Eater{"Eater-2", table, 62643}
  eater3 := &Eater{"Eater-3", table, 38327}
  go maker1.Start()
  go maker2.Start()
  go maker3.Start()
  go eater1.Start()
  go eater2.Start()
  go eater3.Start()
  for {
    time.Sleep(100)
  }
}

Channel役 goだとそのまんまですね...

ええなあ