Shop.java

package onlineshop;

import onlineshop.enums.Sorting;
import onlineshop.merchandise.Book;
import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVRecord;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import java.io.FileReader;
import java.io.Reader;
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import java.util.concurrent.ThreadLocalRandom;

/**
 * Manages the Shop
 */
@SpringBootApplication
public class Shop {
    public static final DecimalFormat df = new DecimalFormat("0.00", DecimalFormatSymbols.getInstance(Locale.US));
    private final static Logger log = LogManager.getLogger(Shop.class);
    private final static List<Book> books = new ArrayList<>(220);

    public static void main(String[] args) {
        Shop shop = new Shop();
        shop.readArticles("src/main/resources/books.csv");
        SpringApplication.run(Shop.class, args);
        log.info("Server started on http://localhost:8080");
    }

    public List<Book> getArticles() {
        return books;
    }

    /**
     * Returns a sublist of articles
     * @param from {@link Integer}
     * @param to   {@link Integer}
     * @return articlesSublist {@link List<Book>}
     */
    public List<Book> sortAndPaginateArticles(Sorting sorting, int from, int to) {
        sortArticles(sorting);
        return books.subList(from, to);
    }

    /**
     * Sorts the articles (i.e. the original List!) depending on the sorting
     * @param sorting {@link Sorting}
     */
    private void sortArticles(Sorting sorting) {
        switch (sorting) {
            case DEFAULT:
            case ALPHA_UP:
                books.sort((a, b) -> a.getTitle().compareTo(b.getTitle()));
                break;
            case ALPHA_DOWN:
                books.sort((a, b) -> b.getTitle().compareTo(a.getTitle()));
                break;
            case PRICE_UP:
                books.sort((a, b) -> (int) (a.getPrice() * 100 - b.getPrice() * 100));
                break;
            case PRICE_DOWN:
                books.sort((a, b) -> (int) (b.getPrice() * 100 - a.getPrice() * 100));
                break;
/*
            case AUTHOR_UP:
                books.sort(Comparator.comparing(Book::getAuthor)); break;
            case AUTHOR_DOWN:
                books.sort(Comparator.comparing(Book::getAuthor).reversed()); break;
*/
        }
    }

    public int getNumOfArticles() {
        return books.size();
    }

    /**
     * Read articles from a CSV file
     * @param fileName {@link String}
     */
    void readArticles(String fileName) {
        try {
            Reader in = new FileReader(fileName);
            CSVFormat csvFormat = CSVFormat.EXCEL.withFirstRecordAsHeader().builder()
                    .setDelimiter(';')
                    .build();
            Iterable<CSVRecord> records = csvFormat.parse(in);
            ThreadLocalRandom random = ThreadLocalRandom.current();

            for (CSVRecord record : records) {
                String title = record.get("title");
                String author = record.get("author");
                String publisher = record.get("publisher");
                String genre = record.get("genre");


                String priceString = record.get("price");
                double price = !priceString.isEmpty() ?
                        Double.parseDouble(priceString) :
                        random.nextDouble(5.0, 20.01); // random price between 5 and 20$

                price = Math.round(price * 100) / 100d;

                String image = record.get("image");
                if (image.isEmpty()) image = "/images/book-placeholder.png";

                Book book = new Book(title, author, publisher, genre, price, image);
                Integer articleNo = Integer.valueOf(record.get("id"));
                book.setArticleNo(articleNo);
                books.add(book);
            }
            in.close();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        log.info("{} books imported", books.size());
    }

    /**
     * Gets an article/book by its article number
     * @param articleNo {@link Integer}
     * @return existingBook {@link Book}
     */
    public Book getArticleByNumber(int articleNo) {
        for (Book book : books) {
            if (book.getArticleNo() == articleNo)
                return book;
        }
        return null;
    }
}