package com.example.datacollect.service; import java.security.PublicKey; import java.util.ArrayList; import java.util.List; public class HistoryManager implements HistoryService{ private final List history=new ArrayList<>(); private static final int MAX_SIZE=100; @Override public void add(String command){ if (command == null || command.trim().isEmpty()) { return; } history.add(command.trim()); if (history.size() > MAX_SIZE) { history.remove(0); } } @Override public List getHistory() { return new ArrayList<>(history); } @Override public void clear() { history.clear(); } @Override public String get(int index) { if (index >= 0 && index < history.size()) { return history.get(index); } return null; } }