【搞懂设计模式】命令模式:从遥控器到编程的妙用！

// 游戏模拟器操作接口
interface Command {
    void execute();
}

class GameConsole {
    public void start_game() {
        System.out.println("游戏开启!");
    }

    public void stop_game() {
        System.out.println("游戏关闭!");
    }
}

// 启动命令
class StartCommand implements Command {
    GameConsole console;

    public StartCommand(GameConsole console) {
        this.console = console;
    }

    public void execute() {
        console.start_game();
    }
}

// 停止命令
class StopCommand implements Command {
    GameConsole console;

    public StopCommand(GameConsole console) {
        this.console = console;
    }

    public void execute() {
        console.stop_game();
    }
}

// 游戏模拟器
class GameSimulator {
    HashMap<String, Command> commands = new HashMap<>();

    public void register(String cmd_name, Command command) {
        commands.put(cmd_name, command);
    }

    public void execute(String cmd_name) {
        if (commands.containsKey(cmd_name)) {
            Command command = commands.get(cmd_name);
            command.execute();
        } else {
            System.out.println("Unknown command!");
        }
    }
}

public class Main {
    public static void main(String[] args) {
        GameSimulator simulator = new GameSimulator();
        GameConsole console = new GameConsole();
        simulator.register("START", new StartCommand(console));
        simulator.register("STOP", new StopCommand(console));

        simulator.execute("START");
        simulator.execute("STOP");
    }
}

interface Command {
    void execute();
    void undo();
}

class AddTextCommand implements Command {
    private String textToAdd;
    private TextEditor editor;

    public AddTextCommand(String textToAdd, TextEditor editor) {
        this.textToAdd = textToAdd;
        this.editor = editor;
    }

    public void execute() {
        editor.addText(textToAdd);
    }

    public void undo() {
        editor.removeText(textToAdd);
    }
}

class TextEditor {
    private StringBuilder text = new StringBuilder();

    public void addText(String textToAdd) {
        text.append(textToAdd);
    }

    public void removeText(String textToRemove) {
        int index = text.lastIndexOf(textToRemove);
        if (index != -1) {
            text.delete(index, index + textToRemove.length());
        }
    }

    public void printText() {
        System.out.println(text.toString());
    }
}

class TextEditorDriver {
    private Stack<Command> commandHistory = new Stack<>();

    public void executeCommand(Command cmd) {
        cmd.execute();
        commandHistory.push(cmd);
    }

    public void undoLastCommand() {
        if (!commandHistory.isEmpty()) {
            Command lastCmd = commandHistory.pop();
            lastCmd.undo();
        }
    }
}