Implement Pagination For Quiz Search Results

src/main/java/org/wa55death405/quizhub/advices/ControllerExceptionHandler.java

@@ -5,6 +5,7 @@
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.ControllerAdvice;
 import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.method.annotation.MethodArgumentTypeMismatchException;
 import org.wa55death405.quizhub.dto.StandardApiResponse;
 import org.wa55death405.quizhub.enums.StandardApiStatus;
 import org.wa55death405.quizhub.exceptions.InputValidationException;
@@ -18,6 +19,12 @@ this class is the controller advice
     it is used to handle the exceptions thrown by the controllers
  */
 
+/*
+    TODO:
+      separate the exception handlers into different classes
+      * one for predefined spring or library exceptions
+      * one for custom exceptions
+ */
 @ControllerAdvice
 public class ControllerExceptionHandler {
 
@@ -40,4 +47,9 @@ public ResponseEntity<StandardApiResponse<Void>> handleRateLimitReachedException
     public ResponseEntity<StandardApiResponse<Void>> handleFileNotFoundException(FileNotFoundException e) {
         return new ResponseEntity<>(new StandardApiResponse<>(StandardApiStatus.FAILURE, "File not found"), HttpStatus.NOT_FOUND);
     }
+
+    @ExceptionHandler(MethodArgumentTypeMismatchException.class)
+    public ResponseEntity<StandardApiResponse<Void>> handleMethodArgumentTypeMismatchException(MethodArgumentTypeMismatchException e) {
+        return new ResponseEntity<>(new StandardApiResponse<>(StandardApiStatus.FAILURE, "Invalid value for parameter "+ e.getPropertyName() +". Expected type: "+ e.getRequiredType()), HttpStatus.BAD_REQUEST);
+    }
 }

src/main/java/org/wa55death405/quizhub/controllers/QuizController.java

@@ -4,6 +4,7 @@
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
+import org.wa55death405.quizhub.dto.StandardPageList;
 import org.wa55death405.quizhub.dto.questionAttempt.QuestionAttemptSubmissionDTO;
 import org.wa55death405.quizhub.dto.quiz.QuizCreationDTO;
 import org.wa55death405.quizhub.dto.StandardApiResponse;
@@ -32,11 +33,16 @@ public class QuizController {
     /*
         this api is used to get search for quizzes
         it takes the title of the quiz as a query parameter
+        along with the page number and the size of the page
         and returns a list of quizzes that match the title
      */
     @GetMapping("/search")
-    public ResponseEntity<StandardApiResponse<List<QuizGeneralInfoDTO>>> searchQuizzes(@RequestParam(required = false,defaultValue = "") String title) {
-        return new ResponseEntity<>(new StandardApiResponse<>(StandardApiStatus.SUCCESS,"Quizzes fetched successfully",quizService.searchQuizzes(title)), HttpStatus.OK);
+    public ResponseEntity<StandardApiResponse<StandardPageList<QuizGeneralInfoDTO>>> searchQuizzes(
+            @RequestParam(defaultValue = "") String title,
+            @RequestParam(defaultValue = "0") int page,
+            @RequestParam(defaultValue = "10") int size
+    ) {
+        return new ResponseEntity<>(new StandardApiResponse<>(StandardApiStatus.SUCCESS,"Quizzes fetched successfully",quizService.searchQuizzes(title, page, size)), HttpStatus.OK);
     }
 
     /*

src/main/java/org/wa55death405/quizhub/dto/StandardPageList.java

@@ -0,0 +1,17 @@
+package org.wa55death405.quizhub.dto;
+
+import lombok.Data;
+
+import java.util.List;
+
+/*
+    * this class is used as standard response for the paginated list
+    * @param <T> the type of the items in the list
+ */
+@Data
+public class StandardPageList<T>{
+    private Integer currentPage;
+    private Integer currentItemsSize;
+    private Long totalItems;
+    private List<T> items;
+}

src/main/java/org/wa55death405/quizhub/interfaces/services/IQuizService.java

@@ -1,5 +1,6 @@
 package org.wa55death405.quizhub.interfaces.services;
 
+import org.wa55death405.quizhub.dto.StandardPageList;
 import org.wa55death405.quizhub.dto.questionAttempt.QuestionAttemptSubmissionDTO;
 import org.wa55death405.quizhub.dto.quiz.QuizGeneralInfoDTO;
 import org.wa55death405.quizhub.dto.quizAttempt.QuizAttemptResultDTO;
@@ -23,7 +24,7 @@ public interface IQuizService {
         * @param title the title to search for
         * @return a list of quizzes that match the title
      */
-    List<QuizGeneralInfoDTO> searchQuizzes(String title);
+    StandardPageList<QuizGeneralInfoDTO> searchQuizzes(String title, int page, int size);
 
     /*
         * create a new quiz

src/main/java/org/wa55death405/quizhub/repositories/QuizRepository.java

@@ -1,11 +1,12 @@
 package org.wa55death405.quizhub.repositories;
 
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.wa55death405.quizhub.entities.Quiz;
 
-import java.util.List;
 import java.util.UUID;
 
 public interface QuizRepository extends JpaRepository<Quiz, UUID> {
-    List<Quiz> findAllByTitleContainingIgnoreCase(String title);
+    Page<Quiz> findAllByTitleContainingIgnoreCase(String title, Pageable pageable);
 }

src/main/java/org/wa55death405/quizhub/services/QuizService.java

@@ -4,7 +4,10 @@
 import jakarta.persistence.EntityNotFoundException;
 import jakarta.transaction.Transactional;
 import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageRequest;
 import org.springframework.stereotype.Service;
+import org.wa55death405.quizhub.dto.StandardPageList;
 import org.wa55death405.quizhub.dto.questionAttempt.QuestionAttemptSubmissionDTO;
 import org.wa55death405.quizhub.dto.quiz.QuizCreationDTO;
 import org.wa55death405.quizhub.dto.quiz.QuizGeneralInfoDTO;
@@ -36,9 +39,14 @@ public class QuizService implements IQuizService{
     private final EntityManager entityManager;
 
     @Override
-    public List<QuizGeneralInfoDTO> searchQuizzes(String title) {
-        List<Quiz> quizzes = quizRepository.findAllByTitleContainingIgnoreCase(title);
-        return quizzes.stream().map(QuizGeneralInfoDTO::new).toList();
+    public StandardPageList<QuizGeneralInfoDTO> searchQuizzes(String title, int page, int size) {
+        Page<Quiz> quizzes = quizRepository.findAllByTitleContainingIgnoreCase(title,PageRequest.of(page, size));
+        StandardPageList<QuizGeneralInfoDTO> standardPageList = new StandardPageList<>();
+        standardPageList.setItems(quizzes.map(QuizGeneralInfoDTO::new).toList());
+        standardPageList.setCurrentPage(quizzes.getNumber());
+        standardPageList.setCurrentItemsSize(quizzes.getNumberOfElements());
+        standardPageList.setTotalItems(quizzes.getTotalElements());
+        return standardPageList;
     }
 
     @Override

src/test/java/org/wa55death405/quizhub/e2e/ApplicationE2ETests.java

@@ -83,6 +83,8 @@ void testQuizLifecycle() throws JsonProcessingException {
         // Search for the quiz
         HashMap<String, String> queryParams = new HashMap<>();
         queryParams.put("title", quizCreationDTO.getTitle());
+        queryParams.put("page", "0");
+        queryParams.put("size", "1");
         given()
                 .queryParams(queryParams)
                 .when()
@@ -92,9 +94,12 @@ void testQuizLifecycle() throws JsonProcessingException {
                 .body("status", equalTo(StandardApiStatus.SUCCESS.toString()))
                 .body("message", notNullValue())
                 .body("data",notNullValue())
-                .body("data",hasSize(equalTo(1)))
-                .body("data[0].id", equalTo(quizId.toString()))
-                .body("data[0].title", equalTo(quizCreationDTO.getTitle()));
+                .body("data.currentPage",equalTo(0))
+                .body("data.currentItemsSize",equalTo(1))
+                .body("data.totalItems",equalTo(1))
+                .body("data.items",hasSize(equalTo(1)))
+                .body("data.items[0].id", equalTo(quizId.toString()))
+                .body("data.items[0].title", equalTo(quizCreationDTO.getTitle()));
 
         // Start an attempt
         var startQuizResponse = given()

src/test/java/org/wa55death405/quizhub/integration/controllers/QuizControllerTest.java

@@ -12,6 +12,7 @@
 import org.springframework.test.context.ActiveProfiles;
 import org.springframework.test.web.servlet.MockMvc;
 import org.wa55death405.quizhub.controllers.QuizController;
+import org.wa55death405.quizhub.dto.StandardPageList;
 import org.wa55death405.quizhub.dto.quiz.QuizCreationDTO;
 import org.wa55death405.quizhub.dto.quiz.QuizGeneralInfoDTO;
 import org.wa55death405.quizhub.dto.quizAttempt.QuizAttemptResultDTO;
@@ -26,6 +27,7 @@
 import org.wa55death405.quizhub.utils.FakeDataRandomGeneratorImpl;
 
 
+import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.Mockito.when;
 
@@ -59,19 +61,26 @@ class QuizControllerTest {
     @Test
     void searchQuizzes() throws Exception {
         // arrange
-        List<QuizGeneralInfoDTO> expectedQuizzes = new ArrayList<>();
+        int page = 0;
+        int size = 10;
+        long totalItems = 10;
+        StandardPageList<QuizGeneralInfoDTO> expectedQuizzes = new StandardPageList<>();
+        expectedQuizzes.setCurrentPage(page);
+        expectedQuizzes.setTotalItems(totalItems);
+        expectedQuizzes.setCurrentItemsSize(size);
+        expectedQuizzes.setItems(new ArrayList<>());
+
         for (int i = 0; i < 10; i++) {
-            UUID id = UUID.randomUUID();
             var quiz = Quiz.builder()
-                    .id(id)
+                    .id(UUID.randomUUID())
                     .title("Quiz " + i)
                     .build();
-            expectedQuizzes.add(new QuizGeneralInfoDTO(quiz));
+            expectedQuizzes.getItems().add(new QuizGeneralInfoDTO(quiz));
         }
-        when(quizService.searchQuizzes(anyString())).thenReturn(expectedQuizzes);
+        when(quizService.searchQuizzes(anyString(),anyInt(),anyInt())).thenReturn(expectedQuizzes);
 
         // act and assert
-        this.mockMvc.perform(get("/api/quiz/search"))
+        this.mockMvc.perform(get("/api/quiz/search?page={page}&size={size}", page, size))
                 .andExpect(status().isOk())
                 .andDo(document(
                         "search-quizzes",