[#12048] Remove null default section

src/main/java/teammates/common/util/Const.java

@@ -5,8 +5,6 @@
 import java.time.Duration;
 import java.time.Instant;
 
-import teammates.storage.sqlentity.Section;
-
 /**
  * Stores constants that are widely used across classes.
  * this class contains several nested classes, each containing a specific
@@ -27,7 +25,6 @@ public final class Const {
     public static final int SECTION_SIZE_LIMIT = 100;
 
     public static final String DEFAULT_SECTION = "None";
-    public static final Section DEFAULT_SQL_SECTION = null;
 
     public static final String UNKNOWN_INSTITUTION = "Unknown Institution";
 

src/main/java/teammates/sqllogic/api/Logic.java

@@ -22,6 +22,7 @@
 import teammates.common.exception.InvalidParametersException;
 import teammates.common.exception.SearchServiceException;
 import teammates.common.exception.StudentUpdateException;
+import teammates.common.util.Const;
 import teammates.sqllogic.core.AccountRequestsLogic;
 import teammates.sqllogic.core.AccountsLogic;
 import teammates.sqllogic.core.CoursesLogic;
@@ -1089,6 +1090,14 @@ public List<Student> getStudentsByTeamName(String teamName, String courseId) {
         return usersLogic.getStudentsForTeam(teamName, courseId);
     }
 
+    /**
+     * Returns the default SQL section.
+     * If it does not exist, create and return it.
+     */
+    public Section getDefaultSectionOrCreate(String courseId) {
+        return getSectionOrCreate(courseId, Const.DEFAULT_SECTION);
+    }
+
     /**
      * Gets a team by associated {@code courseId} and {@code sectionName}.
      */

src/main/java/teammates/ui/webapi/BasicFeedbackSubmissionAction.java

@@ -434,35 +434,35 @@ Section getRecipientSection(
             switch (giverType) {
             case INSTRUCTORS:
             case SELF:
-                return Const.DEFAULT_SQL_SECTION;
+                return sqlLogic.getDefaultSectionOrCreate(courseId);
             case TEAMS:
             case TEAMS_IN_SAME_SECTION:
                 Section section = sqlLogic.getSectionByCourseIdAndTeam(courseId, recipientIdentifier);
-                return section == null ? Const.DEFAULT_SQL_SECTION : section;
+                return section == null ? sqlLogic.getDefaultSectionOrCreate(courseId) : section;
             case STUDENTS:
             case STUDENTS_IN_SAME_SECTION:
                 Student student = sqlLogic.getStudentForEmail(courseId, recipientIdentifier);
-                return student == null ? Const.DEFAULT_SQL_SECTION : student.getSection();
+                return student == null ? sqlLogic.getDefaultSectionOrCreate(courseId) : student.getSection();
             default:
                 assert false : "Invalid giver type " + giverType + " for recipient type " + recipientType;
                 return null;
             }
         case INSTRUCTORS:
         case NONE:
-            return Const.DEFAULT_SQL_SECTION;
+            return sqlLogic.getDefaultSectionOrCreate(courseId);
         case TEAMS:
         case TEAMS_EXCLUDING_SELF:
         case TEAMS_IN_SAME_SECTION:
         case OWN_TEAM:
             Section section = sqlLogic.getSectionByCourseIdAndTeam(courseId, recipientIdentifier);
-            return section == null ? Const.DEFAULT_SQL_SECTION : section;
+            return section == null ? sqlLogic.getDefaultSectionOrCreate(courseId) : section;
         case STUDENTS:
         case STUDENTS_EXCLUDING_SELF:
         case STUDENTS_IN_SAME_SECTION:
         case OWN_TEAM_MEMBERS:
         case OWN_TEAM_MEMBERS_INCLUDING_SELF:
             Student student = sqlLogic.getStudentForEmail(courseId, recipientIdentifier);
-            return student == null ? Const.DEFAULT_SQL_SECTION : student.getSection();
+            return student == null ? sqlLogic.getDefaultSectionOrCreate(courseId) : student.getSection();
         default:
             assert false : "Unknown recipient type " + recipientType;
             return null;

src/main/java/teammates/ui/webapi/SubmitFeedbackResponsesAction.java

@@ -205,7 +205,7 @@ public JsonResult execute() throws InvalidHttpRequestBodyException, InvalidOpera
         case INSTRUCTOR_SUBMISSION:
             Instructor instructor = getSqlInstructorOfCourseFromRequest(feedbackQuestion.getCourseId());
             giverIdentifier = instructor.getEmail();
-            giverSection = Const.DEFAULT_SQL_SECTION;
+            giverSection = sqlLogic.getDefaultSectionOrCreate(courseId);
             existingResponses = sqlLogic.getFeedbackResponsesFromInstructorForQuestion(feedbackQuestion, instructor);
             recipientsOfTheQuestion = sqlLogic.getRecipientsOfQuestion(feedbackQuestion, instructor, null);
             sqlLogic.populateFieldsToGenerateInQuestion(feedbackQuestion,