java/Crawler/strategy_crawler/CrawlerContext.java

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

public class CrawlerContext {
    private CrawlStrategy<CrawlResult> strategy;

    public CrawlerContext(CrawlStrategy<CrawlResult> strategy) {
        this.strategy = strategy;
    }

    public void setStrategy(CrawlStrategy<CrawlResult> strategy) {
        this.strategy = strategy;
    }

    public List<CrawlResult> executeCrawl(int startPage, int endPage) {
        List<CrawlResult> allResults = new ArrayList<CrawlResult>();
        for (int page = startPage; page <= endPage; page++) {
            try {
                List<CrawlResult> pageResults = strategy.crawlPage(page);
                allResults.addAll(pageResults);
                System.out.println("Crawling " + strategy.getBaseUrl() + " Page " + page + ": " + pageResults.size() + " items");
                Thread.sleep(500);
            } catch (IOException e) {
                System.err.println("Error crawling page " + page + ": " + e.getMessage());
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
                break;
            }
        }
        return allResults;
    }

    public void executeCrawlAndSave(int startPage, int endPage, String filename) {
        List<CrawlResult> results = executeCrawl(startPage, endPage);
        saveToFile(results, filename);
        System.out.println("Crawl completed, " + results.size() + " items saved to " + filename);
    }

    private void saveToFile(List<CrawlResult> results, String filename) {
        try (PrintWriter writer = new PrintWriter(new OutputStreamWriter(new FileOutputStream(filename), "UTF-8"))) {
            writer.println("Title,Price,OriginalPrice,Discount,ImageUrl,AuthorOrSeller");
            for (CrawlResult result : results) {
                writer.printf("%s,%.2f,%.2f,%.1f,%s,%s%n",
                        result.getTitle(),
                        result.getPrice(),
                        result.getOriginalPrice(),
                        result.getDiscount(),
                        result.getImageUrl(),
                        result.getAuthorOrSeller());
            }
        } catch (IOException e) {
            System.err.println("Failed to save file: " + e.getMessage());
        }
    }
}