refactoring: createUser method in CreateUser

src/main/java/CreateUser.java

@@ -94,15 +94,25 @@ class CreateUser {
 
     // Function to create user with validation
     public static CreateUser createUser(String id, String userName, String password, String birthday, String firstName, String surname) {
-    	if (userName == null || userName.isEmpty()) {
-        throw new IllegalArgumentException("Username cannot be empty");
+        validateUserName(userName);
+        validatePassword(password);
+
+        return new CreateUser(id, userName, password, birthday, firstName, surname);
+    }
+
+    private static void validateUserName(String userName) {
+        if (userName == null || userName.isEmpty()) {
+            throw new IllegalArgumentException("Username cannot be empty");
         }
+    }
+
+    private static void validatePassword(String password) {
         if (password == null || password.isEmpty()) {
-        throw new IllegalArgumentException("Password cannot be empty");
+            throw new IllegalArgumentException("Password cannot be empty");
         }
         if (password.length() < 6) {
-        throw new IllegalArgumentException("Password must be at least 6 characters long");
-        }    return new CreateUser(id, userName, password, birthday, firstName, surname);
+            throw new IllegalArgumentException("Password must be at least 6 characters long");
+        }
     }
     
     // Function to hash the password using SHA-256 algorithm

user.json

@@ -1,47 +1,2 @@
 [
-  {
-    "id": "d7ae19fe-4684-4d69-a73d-4cca612962a3",
-    "userName": "Test",
-    "password": "8d969eef6ecad3c29a3a629280e686cf0c3f5d5a86aff3ca12020c923adc6c92",
-    "birthday": "",
-    "firstName": "",
-    "surname": "",
-    "stayLoggedIn": false
-  },
-  {
-    "id": "2ec2c0c5-677c-4262-8958-fef98d11cc63",
-    "userName": "Test2",
-    "password": "8d969eef6ecad3c29a3a629280e686cf0c3f5d5a86aff3ca12020c923adc6c92",
-    "birthday": "",
-    "firstName": "",
-    "surname": "",
-    "stayLoggedIn": false
-  },
-  {
-    "id": "ccfcc294-48ad-49db-996f-d7c99a93bac9",
-    "userName": "testuser",
-    "password": "5e884898da28047151d0e56f8dc6292773603d0d6aabbdd62a11ef721d1542d8",
-    "birthday": "2000-01-01",
-    "firstName": "John",
-    "surname": "Doe",
-    "stayLoggedIn": false
-  },
-  {
-    "id": "27ffc70f-dd76-4765-81e3-76fde9b618e5",
-    "userName": "testUser",
-    "password": "5e884898da28047151d0e56f8dc6292773603d0d6aabbdd62a11ef721d1542d8",
-    "birthday": "1990-01-01",
-    "firstName": "John",
-    "surname": "Doe",
-    "stayLoggedIn": false
-  },
-  {
-    "id": "731fda82-6b51-4f3f-ae97-c9b01c9b4a1a",
-    "userName": "existinguser",
-    "password": "5e884898da28047151d0e56f8dc6292773603d0d6aabbdd62a11ef721d1542d8",
-    "birthday": "1990-01-01",
-    "firstName": "John",
-    "surname": "Doe",
-    "stayLoggedIn": false
-  }
 ]