java/W9/HistoryCommand.java

import java.util.ArrayList;
import java.util.List;

public class HistoryCommand {
    private final List<String> commandHistory = new ArrayList<>();

    public void addCommand(String command) {
        commandHistory.add(command);
    }

    // 返回副本，避免外部直接修改内部列表
    public List<String> getHistory() {
        return new ArrayList<>(commandHistory);
    }

    public void printHistory() {
        System.out.println("=== 命令历史 ===");
        for (int i = 0; i < commandHistory.size(); i++) {
            System.out.printf("%d: %s%n", i + 1, commandHistory.get(i));
        }
    }

    public void clearHistory() {
        commandHistory.clear();
    }
}