java/project/command/CommandHistory.java

package com.crawler.command;

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

public class CommandHistory {
    private static CommandHistory instance;
    private List<String> history;

    private CommandHistory() {
        history = new ArrayList<>();
    }

    public static CommandHistory getInstance() {
        if (instance == null) {
            instance = new CommandHistory();
        }
        return instance;
    }

    public void add(String command) {
        history.add(command);
    }

    public List<String> getHistory() {
        return new ArrayList<>(history);
    }

    public void clear() {
        history.clear();
    }

    public int size() {
        return history.size();
    }
}