876: Added optional to all of the nullable function returns in POTDRe…

src/main/java/org/patinanetwork/codebloom/api/submission/SubmissionController.java

@@ -264,12 +264,11 @@ public ResponseEntity<ApiResponder<PotdDto>> getCurrentPotd(final HttpServletReq
         AuthenticationObject authenticationObject = protector.validateSession(request);
         User user = authenticationObject.getUser();
 
-        POTD potd = potdRepository.getCurrentPOTD();
-
-        if (potd == null || !isSameDay(potd.getCreatedAt())) {
-            return ResponseEntity.status(HttpStatus.NOT_FOUND)
-                    .body(ApiResponder.failure("Sorry, no problem of the day today!"));
-        }
+        POTD potd = potdRepository
+                .getCurrentPOTD()
+                .filter(p -> isSameDay(p.getCreatedAt()))
+                .orElseThrow(
+                        () -> new ResponseStatusException(HttpStatus.NOT_FOUND, "Sorry, no problem of the day today!"));
 
         boolean alreadyCompleted = questionRepository
                 .getQuestionBySlugAndUserId(potd.getSlug(), user.getId())
@@ -303,12 +302,11 @@ public ResponseEntity<ApiResponder<PotdDto>> getCurrentPotd(final HttpServletReq
     public ResponseEntity<ApiResponder<PotdDto>> getCurrentPotdEmbed() {
         FakeLag.sleep(750);
 
-        POTD potd = potdRepository.getCurrentPOTD();
-
-        if (potd == null || !isSameDay(potd.getCreatedAt())) {
-            return ResponseEntity.status(HttpStatus.NOT_FOUND)
-                    .body(ApiResponder.failure("Sorry, no problem of the day today!"));
-        }
+        POTD potd = potdRepository
+                .getCurrentPOTD()
+                .filter(p -> isSameDay(p.getCreatedAt()))
+                .orElseThrow(
+                        () -> new ResponseStatusException(HttpStatus.NOT_FOUND, "Sorry, no problem of the day today!"));
 
         return ResponseEntity.ok()
                 .body(ApiResponder.success("Problem of the day has been fetched!", PotdDto.fromPOTD(potd)));

src/main/java/org/patinanetwork/codebloom/common/db/repos/potd/POTDRepository.java

@@ -1,14 +1,15 @@
 package org.patinanetwork.codebloom.common.db.repos.potd;
 
 import java.util.ArrayList;
+import java.util.Optional;
 import org.patinanetwork.codebloom.common.db.models.potd.POTD;
 
 public interface POTDRepository {
     POTD createPOTD(POTD potd);
 
-    POTD getPOTDById(String id);
+    Optional<POTD> getPOTDById(String id);
 
-    POTD getCurrentPOTD();
+    Optional<POTD> getCurrentPOTD();
 
     ArrayList<POTD> getAllPOTDS();
 

src/main/java/org/patinanetwork/codebloom/common/db/repos/potd/POTDSqlRepository.java

@@ -5,6 +5,7 @@
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
+import java.util.Optional;
 import java.util.UUID;
 import javax.sql.DataSource;
 import org.patinanetwork.codebloom.common.db.models.potd.POTD;
@@ -56,22 +57,22 @@ public POTD createPOTD(final POTD potd) {
     }
 
     @Override
-    public POTD getPOTDById(final String id) {
+    public Optional<POTD> getPOTDById(final String id) {
         String sql = "SELECT id, \"title\", \"slug\", \"multiplier\", \"createdAt\" FROM \"POTD\" WHERE id = ?";
 
         try (Connection conn = ds.getConnection();
                 PreparedStatement stmt = conn.prepareStatement(sql)) {
             stmt.setObject(1, UUID.fromString(id));
             try (ResultSet rs = stmt.executeQuery()) {
                 if (rs.next()) {
-                    return mapRowToPOTD(rs);
+                    return Optional.of(mapRowToPOTD(rs));
                 }
             }
         } catch (SQLException e) {
             throw new RuntimeException("Failed to get POTD by id", e);
         }
 
-        return null;
+        return Optional.empty();
     }
 
     @Override
@@ -118,7 +119,7 @@ public void deletePOTD(final String id) {
     }
 
     @Override
-    public POTD getCurrentPOTD() {
+    public Optional<POTD> getCurrentPOTD() {
         String sql = """
             SELECT "id", "title", "slug", "multiplier", "createdAt"
             FROM "POTD"
@@ -130,11 +131,11 @@ public POTD getCurrentPOTD() {
                 PreparedStatement stmt = conn.prepareStatement(sql);
                 ResultSet rs = stmt.executeQuery()) {
             if (rs.next()) {
-                return mapRowToPOTD(rs);
+                return Optional.of(mapRowToPOTD(rs));
             }
         } catch (SQLException e) {
             throw new RuntimeException("Failed to get current POTD", e);
         }
-        return null;
+        return Optional.empty();
     }
 }

src/main/java/org/patinanetwork/codebloom/common/submissions/SubmissionsHandler.java

@@ -109,7 +109,7 @@ public static <T> Predicate<T> distinctByKey(final Function<? super T, ?> keyExt
     public ArrayList<AcceptedSubmission> handleSubmissions(
             final List<LeetcodeSubmission> leetcodeSubmissions, final User user, boolean fast) {
         ArrayList<AcceptedSubmission> acceptedSubmissions = new ArrayList<>();
-        POTD potd = potdRepository.getCurrentPOTD();
+        Optional<POTD> potd = potdRepository.getCurrentPOTD();
 
         var questionMap = leetcodeSubmissions.parallelStream()
                 .filter(distinctByKey(LeetcodeSubmission::getTitleSlug))
@@ -154,14 +154,10 @@ public ArrayList<AcceptedSubmission> handleSubmissions(
                     .getQuestionBySlugAndUserId(leetcodeSubmission.getTitleSlug(), user.getId())
                     .isPresent();
 
-            float multiplier;
-            if (potd == null
-                    || !isValid(potd.getCreatedAt())
-                    || !Objects.equals(potd.getSlug(), leetcodeSubmission.getTitleSlug())) {
-                multiplier = 1.0f;
-            } else {
-                multiplier = potd.getMultiplier();
-            }
+            float multiplier = potd.filter(currentPotd -> isValid(currentPotd.getCreatedAt())
+                            && Objects.equals(currentPotd.getSlug(), leetcodeSubmission.getTitleSlug()))
+                    .map(POTD::getMultiplier)
+                    .orElse(1.0f);
 
             QuestionBank bankQuestion = questionMap.get(leetcodeSubmission.getTitleSlug());
 

src/main/java/org/patinanetwork/codebloom/scheduled/potd/PotdSetter.java

@@ -1,5 +1,6 @@
 package org.patinanetwork.codebloom.scheduled.potd;
 
+import java.util.Optional;
 import org.patinanetwork.codebloom.common.db.models.potd.POTD;
 import org.patinanetwork.codebloom.common.db.repos.potd.POTDRepository;
 import org.patinanetwork.codebloom.common.leetcode.LeetcodeClient;
@@ -35,8 +36,9 @@ public void setPotd() {
             return;
         }
 
-        POTD currentPotd = potdRepository.getCurrentPOTD();
-        if (currentPotd != null && currentPotd.getTitle().equals(leetcodePotd.getTitle())) {
+        Optional<POTD> potd = potdRepository.getCurrentPOTD();
+
+        if (potd.map(p -> p.getTitle().equals(leetcodePotd.getTitle())).orElse(false)) {
             // It's already the latest POTD, don't want to do it again.
             LOGGER.info("POTD has already been set before, will not be doing it again.");
             return;

src/test/java/org/patinanetwork/codebloom/api/submission/SubmissionControllerTest.java

@@ -213,7 +213,7 @@ void testGetCurrentPotdSuccess() {
         when(auth.getUser()).thenReturn(user);
         when(user.getId()).thenReturn("abcdefg123456");
 
-        when(potdRepository.getCurrentPOTD()).thenReturn(potd);
+        when(potdRepository.getCurrentPOTD()).thenReturn(Optional.of(potd));
         when(potd.getCreatedAt()).thenReturn(LocalDateTime.now());
         when(potd.getSlug()).thenReturn("two-sum");
 
@@ -240,19 +240,19 @@ void testGetCurrentPotdFailure() {
 
         when(protector.validateSession(request)).thenReturn(auth);
         when(auth.getUser()).thenReturn(user);
-        when(potdRepository.getCurrentPOTD()).thenReturn(null);
+        when(potdRepository.getCurrentPOTD()).thenReturn(Optional.empty());
 
-        ResponseEntity<ApiResponder<PotdDto>> response = submissionController.getCurrentPotd(request);
+        ResponseStatusException ex =
+                assertThrows(ResponseStatusException.class, () -> submissionController.getCurrentPotd(request));
 
-        assertEquals(HttpStatus.NOT_FOUND, response.getStatusCode());
-        assertFalse(response.getBody().isSuccess());
+        assertEquals(HttpStatus.NOT_FOUND, ex.getStatusCode());
     }
 
     @Test
     void testGetCurrentPotdEmbedSuccess() {
         POTD potd = mock(POTD.class);
 
-        when(potdRepository.getCurrentPOTD()).thenReturn(potd);
+        when(potdRepository.getCurrentPOTD()).thenReturn(Optional.of(potd));
         when(potd.getCreatedAt()).thenReturn(LocalDateTime.now());
 
         ResponseEntity<ApiResponder<PotdDto>> response = submissionController.getCurrentPotdEmbed();
@@ -265,12 +265,12 @@ void testGetCurrentPotdEmbedSuccess() {
 
     @Test
     void testGetCurrentPotdEmbedFailure() {
-        when(potdRepository.getCurrentPOTD()).thenReturn(null);
+        when(potdRepository.getCurrentPOTD()).thenReturn(Optional.empty());
 
-        ResponseEntity<ApiResponder<PotdDto>> response = submissionController.getCurrentPotdEmbed();
+        ResponseStatusException ex =
+                assertThrows(ResponseStatusException.class, () -> submissionController.getCurrentPotdEmbed());
 
-        assertEquals(HttpStatus.NOT_FOUND, response.getStatusCode());
-        assertFalse(response.getBody().isSuccess());
+        assertEquals(HttpStatus.NOT_FOUND, ex.getStatusCode());
     }
 
     @Test

src/test/java/org/patinanetwork/codebloom/common/db/repos/potd/POTDRepositoryTest.java

@@ -1,10 +1,12 @@
 package org.patinanetwork.codebloom.common.db.repos.potd;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.List;
+import java.util.Optional;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Order;
@@ -55,24 +57,24 @@ void testCreatePOTD() {
     @Test
     @Order(2)
     void testGetPOTDById() {
-        POTD fetched = potdRepository.getPOTDById(testPOTD.getId());
-        assertNotNull(fetched);
-        assertTrue(testPOTD.equals(fetched));
+        Optional<POTD> fetched = potdRepository.getPOTDById(testPOTD.getId());
+        assertTrue(fetched.isPresent());
+        assertTrue(Optional.of(testPOTD).equals(fetched));
     }
 
     @Test
     @Order(3)
     void testGetCurrentPOTD() {
-        POTD current = potdRepository.getCurrentPOTD();
-        assertNotNull(current);
-        assertTrue(testPOTD.equals(current));
+        Optional<POTD> current = potdRepository.getCurrentPOTD();
+        assertTrue(current.isPresent());
+        assertTrue(Optional.of(testPOTD).equals(current));
     }
 
     @Test
     @Order(4)
     void testGetAllPOTDS() {
         List<POTD> all = potdRepository.getAllPOTDS();
-        assertNotNull(all);
+        assertFalse(all.isEmpty());
         assertTrue(all.contains(testPOTD));
     }
 
@@ -81,7 +83,7 @@ void testGetAllPOTDS() {
     void testUpdatePOTD() {
         testPOTD.setTitle("Updated Title");
         potdRepository.updatePOTD(testPOTD);
-        POTD updated = potdRepository.getPOTDById(testPOTD.getId());
-        assertEquals("Updated Title", updated.getTitle());
+        Optional<POTD> updated = potdRepository.getPOTDById(testPOTD.getId());
+        assertEquals("Updated Title", updated.get().getTitle());
     }
 }

src/test/java/org/patinanetwork/codebloom/common/submissions/SubmissionsHandlerTest.java

@@ -93,7 +93,7 @@ private LeetcodeQuestion leetcodeQuestion(String slug, String difficulty, float
     @BeforeEach
     void commonStubs() {
         when(leaderboardRepository.getRecentLeaderboardMetadata()).thenReturn(Optional.of(leaderboard));
-        when(potdRepository.getCurrentPOTD()).thenReturn(null);
+        when(potdRepository.getCurrentPOTD()).thenReturn(Optional.empty());
 
         when(questionRepository.createQuestion(any(Question.class))).thenAnswer(inv -> {
             Question q = inv.getArgument(0);
@@ -339,14 +339,14 @@ void appliesPotdMultiplier() {
                 .multiplier(2.0f)
                 .createdAt(LocalDateTime.now())
                 .build();
-        when(potdRepository.getCurrentPOTD()).thenReturn(potd);
+        when(potdRepository.getCurrentPOTD()).thenReturn(Optional.of(potd));
 
         LeetcodeSubmission sub = acceptedSubmission(700, "two-sum", LocalDateTime.of(2025, 6, 1, 12, 0));
         when(questionRepository.questionExistsBySubmissionId("700")).thenReturn(false);
         when(questionRepository.getQuestionBySlugAndUserId("two-sum", USER_ID)).thenReturn(Optional.empty());
         when(leetcodeClient.findQuestionBySlug("two-sum")).thenReturn(leetcodeQuestion("two-sum", "Easy", 50f));
 
-        when(potdRepository.getCurrentPOTD()).thenReturn(null);
+        when(potdRepository.getCurrentPOTD()).thenReturn(Optional.empty());
         handler.handleSubmissions(
                 List.of(acceptedSubmission(701, "two-sum", LocalDateTime.of(2025, 6, 1, 12, 0))), user, false);
 
@@ -358,7 +358,7 @@ void appliesPotdMultiplier() {
             q.setId("q-potd");
             return q;
         });
-        when(potdRepository.getCurrentPOTD()).thenReturn(potd);
+        when(potdRepository.getCurrentPOTD()).thenReturn(Optional.of(potd));
 
         ArrayList<AcceptedSubmission> potdResult = handler.handleSubmissions(List.of(sub), user, false);
 

src/test/java/org/patinanetwork/codebloom/scheduled/potd/PotdSetterTest.java

@@ -1,8 +1,10 @@
 package org.patinanetwork.codebloom.scheduled.potd;
 
 import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.*;
 
+import java.util.Optional;
 import java.util.UUID;
 import org.junit.jupiter.api.Test;
 import org.mockito.ArgumentCaptor;
@@ -31,7 +33,7 @@ void testPotdSetterSetPotdWherePotdIsNull() {
     @Test
     void testPotdSetterSetPotdWherePotdIsFoundButStillCurrentPotd() {
         POTD potd = new POTD("Example title", "Example slug", QuestionDifficulty.Easy);
-        org.patinanetwork.codebloom.common.db.models.potd.POTD dbPotd = org.patinanetwork
+        Optional<org.patinanetwork.codebloom.common.db.models.potd.POTD> dbPotd = Optional.of(org.patinanetwork
                 .codebloom
                 .common
                 .db
@@ -44,7 +46,7 @@ void testPotdSetterSetPotdWherePotdIsFoundButStillCurrentPotd() {
                 .multiplier(1.3f)
                 .slug(potd.getTitleSlug())
                 .title(potd.getTitle())
-                .build();
+                .build());
 
         when(leetcodeClient.getPotd()).thenReturn(potd);
         when(potdRepository.getCurrentPOTD()).thenReturn(dbPotd);
@@ -59,7 +61,7 @@ void testPotdSetterSetPotdWherePotdIsFoundButStillCurrentPotd() {
     void testPotdSetterSetPotdWherePotdIsFoundButNoCurrentPotdYet() {
         POTD potd = new POTD("Example title", "Example slug", QuestionDifficulty.Easy);
         when(leetcodeClient.getPotd()).thenReturn(potd);
-        when(potdRepository.getCurrentPOTD()).thenReturn(null);
+        when(potdRepository.getCurrentPOTD()).thenReturn(Optional.empty());
 
         potdSetter.setPotd();
 
@@ -77,7 +79,7 @@ void testPotdSetterSetPotdWherePotdIsFoundButNoCurrentPotdYet() {
     @Test
     void testPotdSetterSetPotdWherePotdIsFoundAndDoesntMatchOldPotd() {
         POTD potd = new POTD("Example title", "Example slug", QuestionDifficulty.Easy);
-        org.patinanetwork.codebloom.common.db.models.potd.POTD oldDbPotd = org.patinanetwork
+        Optional<org.patinanetwork.codebloom.common.db.models.potd.POTD> oldDbPotd = Optional.of(org.patinanetwork
                 .codebloom
                 .common
                 .db
@@ -90,7 +92,7 @@ void testPotdSetterSetPotdWherePotdIsFoundAndDoesntMatchOldPotd() {
                 .multiplier(1.3f)
                 .slug("old slug")
                 .title("old title")
-                .build();
+                .build());
 
         when(leetcodeClient.getPotd()).thenReturn(potd);
         when(potdRepository.getCurrentPOTD()).thenReturn(oldDbPotd);
@@ -105,6 +107,5 @@ void testPotdSetterSetPotdWherePotdIsFoundAndDoesntMatchOldPotd() {
         assertNotNull(dbPotd);
         assertEquals(potd.getTitle(), dbPotd.getTitle());
         assertEquals(potd.getTitleSlug(), dbPotd.getSlug());
-        assertEquals(potd.getDifficulty(), potd.getDifficulty());
     }
 }