documentation: registerUser Method in Administration class

src/main/java/org/example/Administration.java

@@ -160,8 +160,13 @@ public class Administration {
         return null;
     }
 
+    /**
+     * Method to register a  User
+     */
     public void registerUser()
     {
+        //Instance variables
+
         String UserId = null;
         String UserName = null;
 
@@ -178,26 +183,34 @@ public class Administration {
             System.out.println("ID: ");
             UserId = scanner.next();
 
+            //Checks if the entered id is already being used
             if(findProfessorById(UserId) != null || findAdminById(UserId) != null || findStudentById(UserId) != null)
             {
+                //the entered id is used
                 System.out.println("Please enter an ID which is not being used!");
                 correctData = false;
             }
             else if(findProfessorById(UserId) == null || findAdminById(UserId) == null || findStudentById(UserId) == null)
             {
+                //the entered id is not used
+
+                //creates a substring to check if the id-"syntax" is correct
                 String substring = UserId.substring(1);
 
                 if(!rightPrefix(UserId, userType))
                 {
+                    //the prefix is wrong
                     correctData = false;
                 }
                 else if(!isNumber(substring))
                 {
+                    //the substring does not contain only digits
                     System.out.println("Every character besides the first one need to be digits");
                     correctData = false;
 
                 }
                 else{
+                    //the id is not being used and has the right id-"syntax"
                     System.out.println("The Id has not been used already!");
                     correctData = true;
                 }
@@ -206,23 +219,28 @@ public class Administration {
 
             switch (userType)
             {
-                case 1:
+                case 1: //Student
                     Student student = new Student(UserName, UserId, "Student");
                     addStudents(student);
                     break;
-                case 2:
+                case 2: //Admin
                     Admin admin = new Admin(UserName, UserId, "Admin");
                     addAdmin(admin);
                     break;
-                case 3:
+                case 3: //Professor
                     Professor professor = new Professor(UserId, UserName, "Professor");
                     addProfessor(professor);
-                default:
+                default: //Error
                     break;
             }
         }
     }
 
+    /**
+     *
+     * @param substring the userID without the prefixes S (for Student ), A ( Admin), P (Professor)
+     * @return returns true if the substring is only containing digits, returns false either the substring is empty or includes not only digits
+     */
     public boolean isNumber(String substring)
     {
         if(substring == null || substring.isEmpty())
@@ -238,10 +256,17 @@ public class Administration {
         }
         return true;
     }
+
+    /**
+     *
+     * @param userId the userId to be checked
+     * @param i equals userType
+     * @return returns true if the right prefix is being used
+     */
     public boolean rightPrefix(String userId, int i)
     {
         switch (i){
-        case 1:
+        case 1: //Student
             if(userId.startsWith("S"))
             {
                return true;
@@ -257,7 +282,7 @@ public class Administration {
                 return false;
             }
             break;
-        case 2:
+        case 2: //Admin
             if(userId.startsWith("A"))
             {
                 return true;
@@ -273,7 +298,7 @@ public class Administration {
                 return false;
             }
             break;
-        case 3:
+        case 3: //Professor
             if(userId.startsWith("P"))
             {
                 return true;
@@ -290,7 +315,7 @@ public class Administration {
             }
             break;
 
-            default:
+            default: //Error
                 System.out.println("Error");
             break;
         }