feat: adds Rich's Lesson12 CSVDataLoader (#305)

* feat: Lesson12 CSVDataLoader - failing 2 tests.

* fix: altered file paths

* fix: fixes code to make all tests now work

* chore: refactors filepath code to be more succinct

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

@@ -0,0 +1,121 @@
+package com.codedifferently.lesson12.factory.richhawkins;
+
+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.CsvException;
+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() {
+ var model = new LibraryDataModel();
+ model.mediaItems = readMediaItems(("csv/media_items.csv"));
+ model.guests = readGuests(("csv/guests.csv"));
+ Map<String, List<CheckoutModel>> checkoutsByGuestEmail =
+ getCheckedOutItems(("csv/checked_out_items.csv"));
+
+ // Combine checkouts with guests
+ for (LibraryGuestModel guest : model.guests) {
+ List<CheckoutModel> checkouts = checkoutsByGuestEmail.get(guest.email);
+ if (checkouts != null) {
+ guest.checkedOutItems = checkouts;
+ } else {
+ guest.checkedOutItems = new ArrayList<>();
+ }
+ }
+
+ model.guests.forEach(guest -> {});
+
+ return model;
+ }
+
+ private List<MediaItemModel> readMediaItems(String filePath) {
+ List<MediaItemModel> items = new ArrayList<>();
+ try (CSVReader reader =
+ new CSVReader(
+ new FileReader(new ClassPathResource(filePath).getFile()))) { // Skip the header
+ String[] header = reader.readNext();
+ String[] line;
+ while ((line = reader.readNext()) != null) {
+ MediaItemModel item = new MediaItemModel();
+ item.type = line[0];
+ item.id = UUID.fromString(line[1]);
+ item.title = line[2];
+ item.isbn = line[3];
+ item.authors = Arrays.asList(line[4].split("\\s*,\\s*"));
+ // checks for empty index and if empty sets to 0
+ if (line[5].equals("")) item.pages = 0;
+ else item.pages = Integer.parseInt(line[5]);
+ // checks for empty index and sets it to 0 if empty
+ if (line[6].equals("")) item.pages = 0;
+ else item.pages = Integer.parseInt(line[6]);
+ item.edition = line[7];
+ items.add(item);
+ }
+ } catch (IOException e) {
+ throw new RuntimeException("Failed to read CSV file", e);
+ } catch (CsvException e) {
+ throw new RuntimeException("Error parsing CSV file", e);
+ }
+ return items;
+ }
+
+ private List<LibraryGuestModel> readGuests(String filePath) {
+ List<LibraryGuestModel> guests = new ArrayList<>();
+ try (CSVReader reader =
+ new CSVReader(
+ new FileReader(new ClassPathResource(filePath).getFile()))) { // Skip the header
+ String[] header = reader.readNext();
+ 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);
+ }
+ } catch (IOException e) {
+ throw new RuntimeException("Failed to read CSV file", e);
+ } catch (CsvException e) {
+ throw new RuntimeException("Error parsing CSV file", e);
+ }
+ return guests;
+ }
+
+ private Map<String, List<CheckoutModel>> getCheckedOutItems(String filePath) {
+ Map<String, List<CheckoutModel>> checkoutsByGuestEmail = new HashMap<>();
+ try (CSVReader reader =
+ new CSVReader(new FileReader(new ClassPathResource(filePath).getFile()))) {
+ // Skip the header
+ String[] header = reader.readNext();
+ String[] line;
+ while ((line = reader.readNext()) != null) {
+ String email = line[0];
+ CheckoutModel item = new CheckoutModel();
+ item.itemId = UUID.fromString(line[1]);
+ item.dueDate = Instant.parse(line[2]);
+ checkoutsByGuestEmail.computeIfAbsent(email, k -> new ArrayList<>()).add(item);
+ }
+ } catch (IOException e) {
+ throw new RuntimeException("Failed to read checked out items", e);
+ } catch (CsvException e) {
+ throw new RuntimeException("Error parsing CSV file", e);
+ }
+ return checkoutsByGuestEmail;
+ }
+}