java/w11/CrawlCommand.java

package com.example.datacollect.command;

import com.example.datacollect.exception.NetworkException;
import com.example.datacollect.exception.ParseException;
import com.example.datacollect.repository.ArticleRepository;
import com.example.datacollect.strategy.CrawlStrategy;
import com.example.datacollect.strategy.StrategyFactory;
import com.example.datacollect.view.ConsoleView;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class CrawlCommand implements Command {
    private static final Logger logger = LoggerFactory.getLogger(CrawlCommand.class);
    private static final int MAX_RETRIES = 3;
    private static final long RETRY_DELAY_MS = 1000;
    
    private final ConsoleView view;
    private final StrategyFactory strategyFactory;

    public CrawlCommand(ConsoleView view, StrategyFactory strategyFactory) {
        this.view = view;
        this.strategyFactory = strategyFactory;
    }

    @Override
    public String getName() {
        return "crawl";
    }

    @Override
    public void execute(String[] args, ArticleRepository repository) {
        if (args.length < 2) {
            view.printError("Usage: crawl <url>");
            return;
        }
        String url = args[1];
        logger.info("Crawl started for: {}", url);

        CrawlStrategy strategy = strategyFactory.getStrategy(url);
        if (strategy == null) {
            view.printError("No strategy found for: " + url);
            return;
        }

        int retryCount = 0;
        while (retryCount <= MAX_RETRIES) {
            try {
                view.printInfo("Crawling: " + url + (retryCount > 0 ? " (retry " + retryCount + ")" : ""));
                Document doc = Jsoup.connect(url).get();
                var articles = strategy.parse(url, doc);
                for (var article : articles) {
                    repository.add(article);
                }
                view.printSuccess("Crawled " + articles.size() + " articles.");
                return;
            } catch (ParseException e) {
                logger.severe("Parse error for " + url + ": " + e.getMessage());
                view.printError("Parse error: " + e.getMessage());
                return;
            } catch (Exception e) {
                retryCount++;
                if (retryCount > MAX_RETRIES) {
                    logger.severe("Failed to crawl " + url + " after " + MAX_RETRIES + " retries: " + e.getMessage());
                    view.printError("Failed to crawl after " + MAX_RETRIES + " retries: " + e.getMessage());
                    return;
                }
                logger.warning("Network error for " + url + " (attempt " + retryCount + "/" + MAX_RETRIES + "): " + e.getMessage());
                try {
                    Thread.sleep(RETRY_DELAY_MS);
                } catch (InterruptedException ie) {
                    Thread.currentThread().interrupt();
                    logger.severe("Retry interrupted: " + ie.getMessage());
                    view.printError("Crawl interrupted");
                    return;
                }
            }
        }
    }
}