doer.go

package main

import (
  "log"
)

type Manager struct {
  doers []Doer
}

func New() *Manager {
  return &Manager{[]Doer{}}
}

func (m *Manager) Add(d Doer) {
  log.Println("accept doer")
  m.doers = append(m.doers, d)
}

func (m *Manager) Run() {
  for _, doer := range m.doers {
    doer.Do()
  }
}

type Doer interface {
  Do()
}

type MyDoer struct {
  name string
  age  int
}

func (d *MyDoer) Do() {
  log.Printf("Do! %s, %d", d.name, d.age)
}

func main() {
  m := New()
  m.Add(&MyDoer{"tomoya", 28})
  m.Add(&MyDoer{"smagch", 100})
  log.Printf("length is %d", len(m.doers))
  m.Run()
}