command_pattern_study.coffee

# 命令を受けて処理を実行する
class Receiver
  up: ->
    console.log "up"

  down: ->
    console.log "down"

  right: ->
    console.log "right"

  left: ->
    console.log "left"


# 命令のインターフェイスを定義
class Command
  constructor: (@receiver) ->

  action: ->
    # 実際の処理はoverrideして書く


# 実際の命令（上）
class UpCommand extends Command
  constructor: (@receiver) ->
    super @receiver

  # override
  action: ->
    receiver.up()


# 実際の命令（下）
class DownCommand extends Command
  constructor: (@receiver) ->
    super @receiver

  # override
  action: ->
    receiver.down()


# 実際の命令（右）
class RightCommand extends Command
  constructor: (@receiver) ->
    super @receiver

  # override
  action: ->
    receiver.right()


# 実際の命令（左）
class LeftCommand extends Command
  constructor: (@receiver) ->
    super @receiver

  # override
  action: ->
    receiver.left()


# 保持している命令を実行する
class Invoker
  commands: []

  addCommand: (cmd) ->
    @commands.push cmd

  addCommands: (cmds) ->
    @commands = @commands.concat cmds

  reverse: ->
    @commands = @commands.reverse()

  execute: ->
    cmd = @commands.shift()
    if cmd?
      cmd.action()
      return true
    else
      return false

  executeAll: ->
    cmd.action() for cmd in @commands


# 使用例
receiver = new Receiver()
invoker = new Invoker()
invoker.addCommand(new LeftCommand(receiver))
invoker.addCommand(new RightCommand(receiver))
invoker.addCommand(new UpCommand(receiver))
invoker.addCommand(new DownCommand(receiver))
invoker.executeAll() # left, right, up, down