Java - Commandパターン: 呼び出しのカプセル化(マクロコマンド, 状態の管理, undo methodの実装)

Head Firstデザインパターン
頭とからだで覚えるデザインパターンの基本
(オライリージャパン)
Eric Freeman (著), Elisabeth Freeman (著)
Kathy Sierra (著) Bert Bates (著)
佐藤 直生 (監訳), 木下 哲也 (翻訳)
有限会社 福龍興業 (翻訳)

開発環境

• OS X Yosemite - Apple (OS)
• Emacs (CUI)、BBEdit - Bare Bones Software, Inc. (GUI) (Text Editor)
• Java (プログラミング言語)
• javac (コンパイラ)
• java (application launcher)

Head Firstデザインパターン ―頭とからだで覚えるデザインパターンの基本 (Eric Freeman 著、Elisabeth Freeman 著、Kathy Sierra 著、Bert Bates 著、佐藤 直生 監訳、木下 哲也 翻訳、有限会社 福龍興業 翻訳、オライリージャパン)の6章(Commandパターン: 呼び出しのカプセル化)、エクササイズ(p.227)を解いてみる。

その他参考書籍

• Head First Java 第2版 ―頭とからだで覚えるJavaの基本

エクササイズ(p.227)

コード(BBEdit, Emacs)

MacroCommand.java

public class MacroCommand implements Command {
    /* 省略 */

    public void undo() {
        for (int i = 0; i < commands.length; i++) {
            commands[i].undo();
        }
    }
}

入出力結果(Terminal)

$ javac RemoteLoader.java
$ java RemoteLoader
Light is on
Light is off

------ Remote Control -------
[slot 0] LightOnCommand    LightOffCommand
[slot 1] NoCommand    NoCommand
[slot 2] NoCommand    NoCommand
[slot 3] NoCommand    NoCommand
[slot 4] NoCommand    NoCommand
[slot 5] NoCommand    NoCommand
[slot 6] NoCommand    NoCommand
[undo] LightOffCommand

Light is dimmed to 100%
Light is off
Light is on

------ Remote Control -------
[slot 0] LightOnCommand    LightOffCommand
[slot 1] NoCommand    NoCommand
[slot 2] NoCommand    NoCommand
[slot 3] NoCommand    NoCommand
[slot 4] NoCommand    NoCommand
[slot 5] NoCommand    NoCommand
[slot 6] NoCommand    NoCommand
[undo] LightOnCommand

Light is off
Living Room ceiling fan is on medium
Living Room ceiling fan is off

------ Remote Control -------
[slot 0] CeilingFanMediumCommand    CeilingFanOffCommand
[slot 1] CeilingFanHighCommand    CeilingFanOffCommand
[slot 2] NoCommand    NoCommand
[slot 3] NoCommand    NoCommand
[slot 4] NoCommand    NoCommand
[slot 5] NoCommand    NoCommand
[slot 6] NoCommand    NoCommand
[undo] CeilingFanOffCommand

Living Room ceiling fan is on medium
Living Room ceiling fan is on high

------ Remote Control -------
[slot 0] CeilingFanMediumCommand    CeilingFanOffCommand
[slot 1] CeilingFanHighCommand    CeilingFanOffCommand
[slot 2] NoCommand    NoCommand
[slot 3] NoCommand    NoCommand
[slot 4] NoCommand    NoCommand
[slot 5] NoCommand    NoCommand
[slot 6] NoCommand    NoCommand
[undo] CeilingFanHighCommand

Living Room ceiling fan is on medium
$