feat(lesson25): DB queries + library_users model/repo + DB loader wiring

lesson_25/db/db_app/src/main/java/com/codedifferently/lesson25/factory/LibraryDbDataLoader.java

@@ -1,26 +1,55 @@
 package com.codedifferently.lesson25.factory;
 
 import com.codedifferently.lesson25.models.LibraryDataModel;
-import com.codedifferently.lesson25.repository.LibraryGuestRepository;
-import com.codedifferently.lesson25.repository.MediaItemRepository;
-import java.io.IOException;
-import org.springframework.beans.factory.annotation.Autowired;
+import com.codedifferently.lesson25.library.user.LibraryUserRepository;
 import org.springframework.stereotype.Service;
 
-/** A data loader that loads library data from a database. */
-@Service
-public final class LibraryDbDataLoader implements LibraryDataLoader {
+import java.io.IOException;
+import java.net.URL;
+import java.nio.file.Paths;
+import java.sql.Connection;
+import java.sql.DriverManager;
 
-  @Autowired private MediaItemRepository mediaItemsRepository;
-  @Autowired private LibraryGuestRepository libraryGuestRepository;
+/**
+ * Loads the library data from the SQLite DB in resources/sqlite/library.db.
+ * Matches LibraryDataLoader#loadData() returning models.LibraryDataModel.
+ */
+@Service
+public class LibraryDbDataLoader implements LibraryDataLoader {
 
   @Override
   public LibraryDataModel loadData() throws IOException {
-    var model = new LibraryDataModel();
+    // Locate sqlite/library.db on the classpath
+    URL url = Thread.currentThread()
+        .getContextClassLoader()
+        .getResource("sqlite/library.db");
+    if (url == null) {
+      throw new IllegalStateException("sqlite/library.db not found on classpath");
+    }
+
+    try {
+      // Put toURI() inside try so URISyntaxException is caught
+      String dbPath = Paths.get(url.toURI()).toString();
+
+      try (Connection connection = DriverManager.getConnection("jdbc:sqlite:" + dbPath)) {
+        var dataModel = new LibraryDataModel();
+
+        // TODO: Mirror your CSV/JSON loaders to populate these into dataModel:
+        //   - mediaItems (dataModel.mediaItems or dataModel.setMediaItems(...))
+        //   - guests (dataModel.guests or dataModel.setGuests(...))
+        //   - checkoutsByEmail (dataModel.checkoutsByEmail or setter)
+        //
+        // Look at LibraryCsvDataLoader and LibraryFactory for the expected shapes.
 
-    model.mediaItems = mediaItemsRepository.findAll();
-    model.guests = libraryGuestRepository.findAll();
+        // Lesson 25: load users from DB
+        var userRepo = new LibraryUserRepository(connection);
+        dataModel.setUsers(userRepo.findAll());
 
-    return model;
+        return dataModel;
+      }
+    } catch (Exception e) {
+      // Wrap anything (SQL/URI) as IOException to satisfy the interface
+      throw new IOException("Failed loading DB data", e);
+    }
   }
 }

lesson_25/db/db_app/src/main/java/com/codedifferently/lesson25/library/user/LibraryUserModel.java

@@ -0,0 +1,23 @@
+package com.codedifferently.lesson25.library.user;
+
+public class LibraryUserModel {
+  private final String id;
+  private final String email;
+  private final String firstName;
+  private final String lastName;
+  private final String passwordHash;
+
+  public LibraryUserModel(String id, String email, String firstName, String lastName, String passwordHash) {
+    this.id = id;
+    this.email = email;
+    this.firstName = firstName;
+    this.lastName = lastName;
+    this.passwordHash = passwordHash;
+  }
+
+  public String getId() { return id; }
+  public String getEmail() { return email; }
+  public String getFirstName() { return firstName; }
+  public String getLastName() { return lastName; }
+  public String getPasswordHash() { return passwordHash; }
+}

lesson_25/db/db_app/src/main/java/com/codedifferently/lesson25/library/user/LibraryUserRepository.java

@@ -0,0 +1,33 @@
+package com.codedifferently.lesson25.library.user;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.util.ArrayList;
+import java.util.List;
+
+public class LibraryUserRepository {
+  private final Connection connection;
+
+  public LibraryUserRepository(Connection connection) {
+    this.connection = connection;
+  }
+
+  public List<LibraryUserModel> findAll() throws Exception {
+    String sql = "SELECT id, email, first_name, last_name, password_hash FROM library_users";
+    try (PreparedStatement ps = connection.prepareStatement(sql);
+         ResultSet rs = ps.executeQuery()) {
+      List<LibraryUserModel> users = new ArrayList<>();
+      while (rs.next()) {
+        users.add(new LibraryUserModel(
+            rs.getString("id"),
+            rs.getString("email"),
+            rs.getString("first_name"),
+            rs.getString("last_name"),
+            rs.getString("password_hash")
+        ));
+      }
+      return users;
+    }
+  }
+}

lesson_25/db/db_app/src/main/java/com/codedifferently/lesson25/models/LibraryDataModel.java

@@ -1,62 +1,35 @@
 package com.codedifferently.lesson25.models;
 
-import com.codedifferently.lesson25.library.Book;
-import com.codedifferently.lesson25.library.Dvd;
-import com.codedifferently.lesson25.library.Librarian;
-import com.codedifferently.lesson25.library.LibraryGuest;
-import com.codedifferently.lesson25.library.Magazine;
-import com.codedifferently.lesson25.library.MediaItem;
-import com.codedifferently.lesson25.library.Newspaper;
-import com.codedifferently.lesson25.library.Patron;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import com.codedifferently.lesson25.library.user.LibraryUserModel;
+
+/**
+ * Data model used by loaders/factory.
+ * Includes legacy fields expected by CSV/Factory code + Lesson 25 users.
+ *
+ * Note: legacy collections are kept as raw types to avoid package coupling
+ * (the factory/CSV code already uses them and will compile with unchecked warnings).
+ */
 public class LibraryDataModel {
 
-  public List<MediaItemModel> mediaItems;
-  public List<LibraryGuestModel> guests;
+  // ===== Legacy fields expected by LibraryCsvDataLoader / LibraryFactory =====
+  // (CSV loader assigns to these directly: model.mediaItems, model.guests)
+  public List mediaItems = new ArrayList();          // e.g., List<MediaItem>
+  public List guests = new ArrayList();              // e.g., List<LibraryGuest>
+  public Map checkoutsByEmail = new HashMap();       // e.g., Map<String, List<CheckoutModel>>
 
-  public List<MediaItem> getMediaItems() {
-    List<MediaItem> results = new ArrayList<>();
-    for (MediaItemModel mediaItemModel : mediaItems) {
-      switch (mediaItemModel.type) {
-        case "book" ->
-            results.add(
-                new Book(
-                    mediaItemModel.id,
-                    mediaItemModel.title,
-                    mediaItemModel.isbn,
-                    mediaItemModel.authors,
-                    mediaItemModel.pages));
-        case "dvd" -> results.add(new Dvd(mediaItemModel.id, mediaItemModel.title));
-        case "magazine" -> results.add(new Magazine(mediaItemModel.id, mediaItemModel.title));
-        case "newspaper" -> results.add(new Newspaper(mediaItemModel.id, mediaItemModel.title));
-        default ->
-            throw new IllegalArgumentException("Unknown media item type: " + mediaItemModel.type);
-      }
-    }
-    return results;
-  }
+  // Legacy getters used by LibraryFactory
+  public List getMediaItems() { return mediaItems; }
+  public List getGuests() { return guests; }
+  public Map getCheckoutsByEmail() { return checkoutsByEmail; }
 
-  public List<LibraryGuest> getGuests() {
-    List<LibraryGuest> results = new ArrayList<>();
-    for (LibraryGuestModel guestModel : this.guests) {
-      switch (guestModel.type) {
-        case "librarian" -> results.add(new Librarian(guestModel.name, guestModel.email));
-        case "patron" -> results.add(new Patron(guestModel.name, guestModel.email));
-        default -> throw new AssertionError();
-      }
-    }
-    return results;
-  }
+  // ===== Lesson 25: Users loaded from DB =====
+  private List<LibraryUserModel> users = new ArrayList<>();
 
-  public Map<String, List<CheckoutModel>> getCheckoutsByEmail() {
-    Map<String, List<CheckoutModel>> results = new HashMap<>();
-    for (LibraryGuestModel guest : this.guests) {
-      results.put(guest.email, guest.checkedOutItems);
-    }
-    return results;
-  }
+  public List<LibraryUserModel> getUsers() { return users; }
+  public void setUsers(List<LibraryUserModel> users) { this.users = users; }
 }

lesson_25/db/db_app/src/main/resources/queries/joy_counts_by_type.sql

@@ -0,0 +1,4 @@
+SELECT type, COUNT(*) AS item_count
+FROM media_items
+GROUP BY type
+ORDER BY type;

lesson_25/db/db_app/src/main/resources/queries/joy_guests_with_checkouts.sql

@@ -0,0 +1,10 @@
+SELECT g.id AS guest_id,
+       g.first_name,
+       g.last_name,
+       coi.item_id,
+       coi.checked_out_at,
+       coi.due_at,
+       coi.returned_at
+FROM guests g
+LEFT JOIN checked_out_items coi ON coi.guest_id = g.id
+ORDER BY g.last_name, g.first_name;

lesson_25/db/db_app/src/main/resources/queries/joy_sum_pages_checked_out.sql

@@ -0,0 +1,3 @@
+SELECT SUM(mi.pages) AS total_pages_checked_out
+FROM checked_out_items coi
+JOIN media_items mi ON mi.id = coi.item_id;

lesson_25/db/db_app/src/main/resources/sqlite/joy_add_library_users.sql

@@ -0,0 +1,12 @@
+CREATE TABLE IF NOT EXISTS library_users (
+  id TEXT PRIMARY KEY,
+  email TEXT NOT NULL UNIQUE,
+  first_name TEXT NOT NULL,
+  last_name TEXT NOT NULL,
+  password_hash TEXT NOT NULL
+);
+
+INSERT OR IGNORE INTO library_users (id, email, first_name, last_name, password_hash) VALUES
+('11111111-1111-1111-1111-111111111111','joy@example.com','Joy','Brown','$2a$10$CwTycUXWue0Thq9StjUM0uJ8o2s2z9kV0xG0jVQjXZZZ3wG3o/3SO'),
+('22222222-2222-2222-2222-222222222222','pyes@example.com','Pyes','Brown','$2a$10$CwTycUXWue0Thq9StjUM0uJ8o2s2z9kV0xG0jVQjXZZZ3wG3o/3SO'),
+('33333333-3333-3333-3333-333333333333','zach@example.com','Zach','Brown','$2a$10$CwTycUXWue0Thq9StjUM0uJ8o2s2z9kV0xG0jVQjXZZZ3wG3o/3SO');