changes for json convertion

src/main/java/de/tum/in/www1/artemis/domain/quiz/AnswerOptionDTO.java

@@ -1,11 +1,13 @@
 package de.tum.in.www1.artemis.domain.quiz;
 
+import java.io.Serializable;
+
 /**
  * A AnswerOption.
  */
-public class AnswerOptionDTO {
+public class AnswerOptionDTO implements Serializable {
 
-    private Long id;
+    private Long id = 1L;
 
     private String text;
 

src/main/java/de/tum/in/www1/artemis/domain/quiz/SubmittedAnswer.java

@@ -48,6 +48,10 @@ public abstract class SubmittedAnswer extends DomainObject {
     @JsonIgnore
     private AbstractQuizSubmission submission;
 
+    @Column(name = "selection")
+    @JsonView(QuizView.Before.class)
+    private String selection;
+
     public Double getScoreInPoints() {
         return scoreInPoints;
     }
@@ -72,6 +76,14 @@ public void setSubmission(AbstractQuizSubmission quizSubmission) {
         this.submission = quizSubmission;
     }
 
+    public String getSelection() {
+        return selection;
+    }
+
+    public void setSelection(String selection) {
+        this.selection = selection;
+    }
+
     /**
      * Filter out information about correct answers.
      * Calls {@link QuizQuestion#filterForStudentsDuringQuiz()} which removes all relevant fields.

src/main/java/de/tum/in/www1/artemis/repository/aspects/QuizExerciseAspect.java

@@ -0,0 +1,126 @@
+package de.tum.in.www1.artemis.repository.aspects;
+
+import static de.tum.in.www1.artemis.config.Constants.PROFILE_CORE;
+
+import java.util.List;
+
+import jakarta.transaction.Transactional;
+
+import org.aspectj.lang.JoinPoint;
+import org.aspectj.lang.annotation.AfterReturning;
+import org.aspectj.lang.annotation.Aspect;
+import org.aspectj.lang.annotation.Before;
+import org.springframework.context.annotation.Profile;
+import org.springframework.stereotype.Component;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import de.tum.in.www1.artemis.domain.quiz.AnswerOptionDTO;
+import de.tum.in.www1.artemis.domain.quiz.MultipleChoiceQuestion;
+import de.tum.in.www1.artemis.domain.quiz.QuizExercise;
+import de.tum.in.www1.artemis.domain.quiz.QuizQuestion;
+import de.tum.in.www1.artemis.service.QuizExerciseService;
+
+@Profile(PROFILE_CORE)
+@Component
+@Aspect
+@Transactional
+public class QuizExerciseAspect {
+
+    private final QuizExerciseService quizExerciseService;
+
+    public QuizExerciseAspect(QuizExerciseService quizExerciseService) {
+        this.quizExerciseService = quizExerciseService;
+    }
+
+    @Before("execution(* de.tum.in.www1.artemis.repository.QuizExerciseRepository.save*(..)) && args(de.tum.in.www1.artemis.domain.quiz.QuizExercise)")
+    public void beforeSavingQuizExercise(JoinPoint joinPoint) {
+        Object[] args = joinPoint.getArgs();
+        QuizExercise quizExercise = (QuizExercise) args[0];
+
+        processQuizQuestions(quizExercise.getQuizQuestions());
+    }
+
+    @AfterReturning(pointcut = "execution(de.tum.in.www1.artemis.domain.quiz.QuizExercise de.tum.in.www1.artemis.repository.QuizExerciseRepository.find*(..))", returning = "quizExercise")
+    public void afterReturningQuizExercise(QuizExercise quizExercise) {
+        quizExerciseService.deserializeFromJSON(quizExercise.getQuizQuestions());
+    }
+
+    @AfterReturning(pointcut = "execution(java.util.List<de.tum.in.www1.artemis.domain.quiz.QuizExercise> de.tum.in.www1.artemis.repository.QuizExerciseRepository.find*(..))", returning = "quizExercises")
+    public void afterReturningQuizExerciseList(List<QuizExercise> quizExercises) {
+        for (QuizExercise quizExercise : quizExercises) {
+            quizExerciseService.deserializeFromJSON(quizExercise.getQuizQuestions());
+        }
+    }
+
+    /**
+     * Processes a list of quiz questions by converting each question into a JSON string
+     * and setting it as the content of the question. This method iterates over all
+     * questions in the given quiz exercise.
+     *
+     * @param quizQuestions List of quiz questions. It must not be null.
+     * @throws RuntimeException if there is a problem in serializing the question object to JSON.
+     */
+    public void processQuizQuestions(List<QuizQuestion> quizQuestions) {
+        ObjectMapper objectMapper = new ObjectMapper();
+
+        if (quizQuestions != null) {
+            for (QuizQuestion question : quizQuestions) {
+                if (question instanceof MultipleChoiceQuestion) {
+                    question.setContent(serializeToJson(((MultipleChoiceQuestion) question).getAnswerOptions(), objectMapper));
+                }
+            }
+        }
+    }
+
+    /**
+     * Serializes a QuizQuestion object to its JSON representation using the provided ObjectMapper.
+     * This method is called for each individual question during the quiz processing.
+     *
+     * @param answerOptions
+     * @param objectMapper  the ObjectMapper instance used for serialization. It must not be null.
+     * @return String representing the JSON serialized form of the QuizQuestion.
+     * @throws RuntimeException if JSON processing fails, encapsulating the underlying JsonProcessingException.
+     */
+    public String serializeToJson(List<AnswerOptionDTO> answerOptions, ObjectMapper objectMapper) {
+        try {
+            return objectMapper.writeValueAsString(answerOptions);
+        }
+        catch (JsonProcessingException e) {
+            throw new RuntimeException("Error serializing to JSON", e);
+        }
+    }
+
+    /**
+     * Deserializes a list of QuizQuestion objects from their JSON representation.
+     * Each QuizQuestion in the input list is assumed to have its content in a JSON format.
+     * This method attempts to deserialize that JSON content back into QuizQuestion objects,
+     * preserving the original IDs. If any JSON parsing errors occur, a RuntimeException
+     * is thrown encapsulating the original exception.
+     *
+     * @param quizQuestions the list of QuizQuestions with JSON content to be deserialized.
+     * @throws RuntimeException if any JSON parsing errors occur during the deserialization process,
+     *                              encapsulating the underlying JsonProcessingException.
+     */
+    @Transactional
+    public void deserializeFromJSON(List<QuizQuestion> quizQuestions) {
+        ObjectMapper objectMapper = new ObjectMapper();
+
+        if (quizQuestions != null) {
+            for (QuizQuestion quizQuestion : quizQuestions) {
+                if (quizQuestion instanceof MultipleChoiceQuestion) {
+                    try {
+                        List<AnswerOptionDTO> answerOptions = objectMapper.readValue(quizQuestion.getContent(), new TypeReference<>() {
+                        });
+                        ((MultipleChoiceQuestion) quizQuestion).setAnswerOptions(answerOptions);
+                    }
+                    catch (JsonProcessingException e) {
+                        throw new RuntimeException(e);
+                    }
+                }
+            }
+        }
+    }
+}

src/main/java/de/tum/in/www1/artemis/service/QuizExerciseService.java

@@ -25,7 +25,6 @@
 import org.springframework.web.multipart.MultipartFile;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
-import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.ObjectMapper;
 
 import de.tum.in.www1.artemis.config.Constants;
@@ -443,7 +442,6 @@ protected QuizExercise saveAndFlush(QuizExercise quizExercise) {
         // Note: save will automatically remove deleted questions from the exercise and deleted answer options from the questions
         // and delete the now orphaned entries from the database
         log.debug("Save quiz exercise to database: {}", quizExercise);
-        processQuizQuestions(quizExercise);
 
         return quizExerciseRepository.saveAndFlush(quizExercise);
     }
@@ -483,32 +481,4 @@ private String serializeToJson(List<AnswerOptionDTO> answerOptions, ObjectMapper
             throw new RuntimeException("Error serializing to JSON", e);
         }
     }
-
-    /**
-     * Deserializes a list of QuizQuestion objects from their JSON representation.
-     * Each QuizQuestion in the input list is assumed to have its content in a JSON format.
-     * This method attempts to deserialize that JSON content back into QuizQuestion objects,
-     * preserving the original IDs. If any JSON parsing errors occur, a RuntimeException
-     * is thrown encapsulating the original exception.
-     *
-     * @param quizQuestions the list of QuizQuestions with JSON content to be deserialized.
-     * @throws RuntimeException if any JSON parsing errors occur during the deserialization process,
-     *                              encapsulating the underlying JsonProcessingException.
-     */
-    public void deserializeFromJSON(List<QuizQuestion> quizQuestions) {
-        ObjectMapper objectMapper = new ObjectMapper();
-
-        for (QuizQuestion quizQuestion : quizQuestions) {
-            if (quizQuestion instanceof MultipleChoiceQuestion) {
-                try {
-                    List<AnswerOptionDTO> answerOptions = objectMapper.readValue(quizQuestion.getContent(), new TypeReference<>() {
-                    });
-                    ((MultipleChoiceQuestion) quizQuestion).setAnswerOptions(answerOptions);
-                }
-                catch (JsonProcessingException e) {
-                    throw new RuntimeException(e);
-                }
-            }
-        }
-    }
 }

src/main/java/de/tum/in/www1/artemis/service/QuizSubmissionService.java

@@ -11,6 +11,9 @@
 import org.springframework.context.annotation.Profile;
 import org.springframework.stereotype.Service;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
 import de.tum.in.www1.artemis.domain.Result;
 import de.tum.in.www1.artemis.domain.User;
 import de.tum.in.www1.artemis.domain.enumeration.AssessmentType;
@@ -19,6 +22,7 @@
 import de.tum.in.www1.artemis.domain.participation.Participation;
 import de.tum.in.www1.artemis.domain.participation.StudentParticipation;
 import de.tum.in.www1.artemis.domain.quiz.AbstractQuizSubmission;
+import de.tum.in.www1.artemis.domain.quiz.MultipleChoiceSubmittedAnswer;
 import de.tum.in.www1.artemis.domain.quiz.QuizBatch;
 import de.tum.in.www1.artemis.domain.quiz.QuizExercise;
 import de.tum.in.www1.artemis.domain.quiz.QuizSubmission;
@@ -241,4 +245,40 @@ protected QuizSubmission save(QuizExercise quizExercise, QuizSubmission quizSubm
         quizSubmission.setParticipation(this.getParticipation(quizExercise, quizSubmission, user));
         return quizSubmissionRepository.save(quizSubmission);
     }
+
+    /**
+     * Processes a list of quiz questions by converting each question into a JSON string
+     * and setting it as the content of the question. This method iterates over all
+     * questions in the given quiz exercise.
+     *
+     * @param quizSubmission the QuizSubmission object containing the list of submitted answers. It must not be null.
+     * @throws RuntimeException if there is a problem in serializing the question object to JSON.
+     */
+    public void processSubmittedAnswers(QuizSubmission quizSubmission) {
+        ObjectMapper objectMapper = new ObjectMapper();
+
+        for (SubmittedAnswer submittedAnswer : quizSubmission.getSubmittedAnswers()) {
+            if (submittedAnswer instanceof MultipleChoiceSubmittedAnswer) {
+                submittedAnswer.setSelection(serializeToJson(((MultipleChoiceSubmittedAnswer) submittedAnswer).getSelectedOptions(), objectMapper));
+            }
+        }
+    }
+
+    /**
+     * Serializes a QuizQuestion object to its JSON representation using the provided ObjectMapper.
+     * This method is called for each individual question during the quiz processing.
+     *
+     * @param object
+     * @param objectMapper the ObjectMapper instance used for serialization. It must not be null.
+     * @return String representing the JSON serialized form of the QuizQuestion.
+     * @throws RuntimeException if JSON processing fails, encapsulating the underlying JsonProcessingException.
+     */
+    private String serializeToJson(Object object, ObjectMapper objectMapper) {
+        try {
+            return objectMapper.writeValueAsString(object);
+        }
+        catch (JsonProcessingException e) {
+            throw new RuntimeException("Error serializing to JSON", e);
+        }
+    }
 }

src/main/java/de/tum/in/www1/artemis/web/rest/QuizExerciseResource.java

@@ -340,9 +340,6 @@ public ResponseEntity<QuizExercise> getQuizExercise(@PathVariable Long quizExerc
         log.info("REST request to get quiz exercise : {}", quizExerciseId);
         User user = userRepository.getUserWithGroupsAndAuthorities();
         var quizExercise = quizExerciseRepository.findByIdWithQuestionsAndStatisticsAndCompetenciesElseThrow(quizExerciseId);
-        var c = quizExercise.getQuizQuestions();
-        quizExerciseService.deserializeFromJSON(quizExercise.getQuizQuestions());
-        var d = quizExercise.getQuizQuestions();
 
         if (quizExercise.isExamExercise()) {
             authCheckService.checkHasAtLeastRoleForExerciseElseThrow(Role.EDITOR, quizExercise, user);