feat: adds Sherllin's lesson 12 LibraryCsvDataLoader (#308)

* feat: submitting lesson 12

* feat: completed map, tweaked methods and ran tests to parse data

* feat: lesson 12; updated correct relative path

lesson_12/io/io_app/src/main/java/com/codedifferently/lesson12/factory/sherllin/CsvDataLoader.java

@@ -0,0 +1,130 @@
+package com.codedifferently.lesson12.factory.sherllin;
+
+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 java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.Arrays;
+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 CsvDataLoader implements LibraryCsvDataLoader {
+
+ @Override
+ public LibraryDataModel loadData() {
+ // Read media items
+ List<MediaItemModel> mediaItems = readMediaItems("csv/media_items.csv");
+
+ // Read guests
+ List<LibraryGuestModel> guests = readGuests("csv/guests.csv");
+
+ // Read checked-out items
+ Map<String, List<CheckoutModel>> checkoutsByGuestEmail =
+ readCheckoutItems("csv/checked_out_items.csv");
+
+ for (LibraryGuestModel guest : guests) {
+ List<CheckoutModel> checkouts =
+ checkoutsByGuestEmail.getOrDefault(guest.email, new ArrayList<>());
+ guest.checkedOutItems = checkouts;
+ }
+
+ // Construct LibraryDataModel instance with initialized fields
+ LibraryDataModel libraryDataModel = new LibraryDataModel();
+ libraryDataModel.mediaItems = mediaItems;
+ libraryDataModel.guests = guests;
+
+ return libraryDataModel;
+ }
+
+ private List<MediaItemModel> readMediaItems(String filePath) {
+ try (var reader =
+ new BufferedReader(new FileReader(new ClassPathResource(filePath).getFile()))) {
+ var items = new ArrayList<MediaItemModel>();
+ String line;
+ boolean isFirstLine = true;
+ while ((line = reader.readLine()) != null) {
+ if (isFirstLine) {
+ isFirstLine = false;
+ continue;
+ }
+ var parts = line.split(",");
+ var item = new MediaItemModel();
+ item.type = parts[0];
+ item.id = UUID.fromString(parts[1]);
+ item.title = parts[2];
+ item.isbn = parts[3];
+ item.authors = Arrays.asList(parts[4].split(","));
+ item.pages = parts.length > 5 && !parts[5].isEmpty() ? Integer.parseInt(parts[5]) : 0;
+ item.runtime = parts.length > 6 && !parts[6].isEmpty() ? Integer.parseInt(parts[6]) : 0;
+ item.edition = parts.length > 7 ? parts[7] : "";
+ items.add(item);
+ }
+ return items;
+ } catch (IOException e) {
+ throw new RuntimeException("Failed to read media items", e);
+ }
+ }
+
+ private List<LibraryGuestModel> readGuests(String filePath) {
+ try (var reader =
+ new BufferedReader(new FileReader(new ClassPathResource(filePath).getFile()))) {
+ var items = new ArrayList<LibraryGuestModel>();
+ String line;
+ boolean isFirstLine = true;
+ while ((line = reader.readLine()) != null) {
+ if (isFirstLine) {
+ isFirstLine = false;
+ continue;
+ }
+ var parts = line.split(",");
+ var item = new LibraryGuestModel();
+ item.type = parts[0];
+ item.name = parts[1];
+ item.email = parts[2];
+ items.add(item);
+ }
+ return items;
+ } catch (IOException e) {
+ throw new RuntimeException("Failed to read guests", e);
+ }
+ }
+
+ private Map<String, List<CheckoutModel>> readCheckoutItems(String filePath) {
+ try (var reader =
+ new BufferedReader(new FileReader(new ClassPathResource(filePath).getFile()))) {
+ var checkoutMap = new HashMap<String, List<CheckoutModel>>();
+ String line;
+ boolean isFirstLine = true;
+ while ((line = reader.readLine()) != null) {
+ if (isFirstLine) {
+ isFirstLine = false;
+ continue;
+ }
+ var parts = line.split(",");
+ var checkoutModel = new CheckoutModel();
+ checkoutModel.itemId = UUID.fromString(parts[1]);
+ checkoutModel.dueDate = Instant.parse(parts[2]);
+
+ List<CheckoutModel> checkoutModels = checkoutMap.getOrDefault(parts[0], new ArrayList<>());
+
+ checkoutModels.add(checkoutModel);
+
+ checkoutMap.put(parts[0], checkoutModels);
+ }
+ return checkoutMap;
+ } catch (IOException e) {
+ throw new RuntimeException("Failed to read checkout items", e);
+ }
+ }
+}