Update Project

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

@@ -2,6 +2,7 @@ package org.example;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Scanner;
 
 public class Administration {
     /**
@@ -10,6 +11,7 @@ public class Administration {
     private List<Professor> professors;
     private List<Admin> admins;
     private List<Student> students;
+    Scanner scanner = new Scanner(System.in);
 
     /**
      *  Constructor
@@ -158,6 +160,166 @@ public class Administration {
         return null;
     }
 
+    /**
+     * Method to register a  User
+     */
+    public void registerUser()
+    {
+        //Instance variables
+
+        String UserId = null;
+        String UserName = null;
+
+        System.out.println("Enter the type of user (1-Student, 2-Admin, 3-Professor): ");
+        int userType = scanner.nextInt();
+
+
+        boolean correctData = false;
+        while(!correctData)
+        {
+            System.out.println("Enter the User Details!");
+            System.out.println("Name: ");
+            UserName = scanner.next();
+            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!");
+
+            }
+            else if(findProfessorById(UserId) == null || findAdminById(UserId) == null || findStudentById(UserId) == null)
+            {
+                //the entered id is not used
+
+
+                if(!rightPrefix(UserId, userType))
+                {
+                    //the prefix is wrong
+
+                }
+                else if(!isNumber(UserId))
+                {
+                    //the substring does not contain only digits
+                    System.out.println("Every character besides the first one need to be digits");
+
+
+                }
+                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;
+                }
+
+            }
+
+            switch (userType)
+            {
+                case 1: //Student
+                    Student student = new Student(UserName, UserId, "Student");
+                    addStudents(student);
+                    break;
+                case 2: //Admin
+                    Admin admin = new Admin(UserName, UserId, "Admin");
+                    addAdmin(admin);
+                    break;
+                case 3: //Professor
+                    Professor professor = new Professor(UserId, UserName, "Professor");
+                    addProfessor(professor);
+                default: //Error
+                    break;
+            }
+        }
+    }
+
+    /**
+     *
+     * @param userId the userID
+     * @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 userId)
+    {
+        //creates a substring to check if the id-"syntax" is correct
+        String substring = userId.substring(1);
+
+        //if(substring == null || substring.isEmpty())
+        //{
+        //    return false;
+        //}
+        for(char c : substring.toCharArray())
+        {
+            if(!Character.isDigit(c))
+            {
+                return false;
+            }
+        }
+        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: //Student
+            if(!userId.startsWith("S"))
+            {
+                System.out.println("The ID needs to start with a capital S!");
+                return false;
+            }
+            else if(userId.startsWith("s"))
+            {
+                System.out.println("The ID needs to start with a capital S!");
+                return  false;
+            }
+            else
+            {
+                return true;
+            }
+            case 2: //Admin
+            if(!userId.startsWith("A"))
+            {
+                System.out.println("The ID needs to start with a capital A!");
+                return false;
+            }
+            else if(userId.startsWith("a"))
+            {
+                System.out.println("The ID needs to start with a capital A!");
+                return  false;
+            }
+            else
+            {
+                return true;
+            }
+        case 3: //Professor
+            if(!userId.startsWith("P"))
+            {
+                System.out.println("The ID needs to start with a capital P!");
+                return false;
+            }
+            else if(userId.startsWith("p"))
+            {
+                System.out.println("The ID needs to start with a capital P!");
+                return  false;
+            }
+            else
+            {
+                return true;
+            }
+
+            default: //Error
+                System.out.println("Error");
+            break;
+        }
+        return false;
+    }
+
 }
 
 

src/main/java/org/example/Main.java

@@ -4,6 +4,7 @@ import java.util.Scanner;
 public class Main {
     public static void main(String[] args) {System.out.println("Hello world!");
 
+        Administration administration = new Administration();
         Scanner scanner = new Scanner(System.in);
         boolean exit = false;
 
@@ -23,6 +24,7 @@ public class Main {
             switch (choice) {
                 case 1:
                     System.out.println("Register User selected");
+                    administration.registerUser();
                     break;
                 case 2:
                     System.out.println("Enter Student ID and Course Code to enroll:");