feat: adds chukwumaibezim folder with CsvLoader class

lesson_12/io/io_app/src/main/java/com/codedifferently/lesson12/factory/chukwumaibezim/CsvLoader.java

@@ -0,0 +1,101 @@
+package com.codedifferently.lesson12.factory.chukwumaibezim;
+
+import com.codedifferently.lesson12.factory.LibraryCsvDataLoader;
+import com.codedifferently.lesson12.models.CheckoutModel;
+import com.codedifferently.lesson12.models.LibraryDataModel;
+import com.codedifferently.lesson12.models.LibraryGuestModel;
+import com.codedifferently.lesson12.models.MediaItemModel;
+import com.opencsv.CSVReader;
+import com.opencsv.exceptions.CsvValidationException;
+import java.io.FileReader;
+import java.io.IOException;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.stereotype.Service;
+
+@Service
+public class CsvLoader implements LibraryCsvDataLoader {
+
+ @Override
+ public LibraryDataModel loadData() {
+ LibraryDataModel libraryDataModel = new LibraryDataModel();
+ try {
+ libraryDataModel.mediaItems = readMediaItemsFromCsv("csv/media_items.csv");
+ libraryDataModel.guests = readGuestsFromCsv("csv/guests.csv");
+ populateGuestsWithCheckouts("csv/checked_out_items.csv", libraryDataModel.guests);
+ } catch (IOException e) {
+ throw new RuntimeException("Failed to load data from CSV files", e);
+ } catch (CsvValidationException ex) {
+ }
+ return libraryDataModel;
+ }
+
+ private List<MediaItemModel> readMediaItemsFromCsv(String filePath)
+ throws IOException, CsvValidationException {
+ List<MediaItemModel> mediaItems = new ArrayList<>();
+ try (CSVReader reader =
+ new CSVReader(new FileReader(new ClassPathResource(filePath).getFile()))) {
+ reader.skip(1); // Skip header
+ String[] line;
+ while ((line = reader.readNext()) != null) {
+ MediaItemModel mediaItem = new MediaItemModel();
+ mediaItem.type = line[0];
+ mediaItem.id = UUID.fromString(line[1]);
+ mediaItem.title = line[2];
+ mediaItem.isbn = line[3];
+ mediaItem.authors = List.of(line[4].split("\\s*,\\s*"));
+ mediaItem.pages = line[5].isEmpty() ? 0 : Integer.parseInt(line[5]);
+ mediaItem.runtime = line[6].isEmpty() ? 0 : Integer.parseInt(line[6]);
+ mediaItem.edition = line[7];
+ mediaItems.add(mediaItem);
+ }
+ }
+ return mediaItems;
+ }
+
+ private List<LibraryGuestModel> readGuestsFromCsv(String filePath)
+ throws IOException, CsvValidationException {
+ List<LibraryGuestModel> guests = new ArrayList<>();
+ try (CSVReader reader =
+ new CSVReader(new FileReader(new ClassPathResource(filePath).getFile()))) {
+ reader.skip(1); // Skip header
+ String[] line;
+ while ((line = reader.readNext()) != null) {
+ LibraryGuestModel guest = new LibraryGuestModel();
+ guest.type = line[0];
+ guest.name = line[1];
+ guest.email = line[2];
+ guests.add(guest);
+ }
+ }
+ return guests;
+ }
+
+ private void populateGuestsWithCheckouts(String filePath, List<LibraryGuestModel> guests)
+ throws IOException, CsvValidationException {
+ Map<String, List<CheckoutModel>> checkoutsByGuestEmail = new HashMap<>();
+ try (CSVReader reader =
+ new CSVReader(new FileReader(new ClassPathResource(filePath).getFile()))) {
+ reader.skip(1); // Skip header
+ String[] line;
+ while ((line = reader.readNext()) != null) {
+ String email = line[0];
+ CheckoutModel checkout = new CheckoutModel();
+ checkout.itemId = UUID.fromString(line[1]);
+ checkout.dueDate = Instant.parse(line[2]);
+ checkoutsByGuestEmail.computeIfAbsent(email, k -> new ArrayList<>()).add(checkout);
+ }
+ }
+ // Assign checked-out items to respective guests
+ for (LibraryGuestModel guest : guests) {
+ List<CheckoutModel> checkouts =
+ checkoutsByGuestEmail.getOrDefault(guest.email, new ArrayList<>());
+ guest.checkedOutItems = checkouts;
+ }
+ }
+}