In-Memory CLI University Management System

A lightweight, terminal-based University Management System built purely in Java. This application simulates core institutional workflows—including role-based access for Administrators, Professors, and Students—using strict object-oriented design and Java Collections for state management without requiring external files or databases.

🗺️ System Architecture

The application is structured into modular layers to maintain a clean separation of concerns, ensuring high maintainability and robust execution:

• model/ (Data Entities): Contains domain blueprints leveraging object inheritance (e.g., an abstract User base class extended by Student and Professor) along with complex, memory-linked associations like the many-to-many relationship between students and courses.

• registry/ (In-Memory Database Layer): Implements a centralized, thread-safe data context using the Singleton Pattern. It acts as the local system cache, organizing data using fast lookup maps (Map<String, User> and Map<String, Course>).

• cli/ (Presentation & I/O Validation Layer): Controls terminal routing matrices, display menus, and input stream reading. It features a hardened parser mechanism that traps data mismatch anomalies defensively to prevent crash scenarios.

classDiagram
    direction TB

    %% Class Definitions
    class UniversitySystem {
        -Map~String, User~ userRegistry
        -Map~String, Course~ courseRegistry
        +getInstance() UniversitySystem$
        +addUser(User user) void
        +getUser(String id) User
        +addCourse(Course course) void
        +getCourse(String code) Course
        +getAllCourses() void
        +getAllUsers() void
    }

    class User {
        <<abstract>>
        -String id
        -String name
        -String email
        -String password
        -Role role
        +validateCredentials(String id, String password) boolean
        +getId() String
        +getName() String
        +getRole() Role
    }

    class Student {
        -Set~Course~ enrolledCourses
        -Map~String, Grade~ academicTranscript
        +registerCourse(Course course) boolean
        +dropCourse(Course course) boolean
        +getTranscript() Map~String, Grade~
    }

    class Course {
        -String courseCode
        -String title
        -int credits
        -int maxCapacity
        -Professor instructor
        -List~Student~ enrolledRoster
        +addStudent(Student student) boolean
        +removeStudent(Student student) boolean
        +setInstructor(Professor professor) void
        +isFull() boolean
        +getCourseCode() String
        +getInstructor() Professor
        +getTitle() String
        +getCredits() int
    }

    class Professor {
        -String specialization
        -List~Course~ teachingSchedule
        +assignCourse(Course course) void
        +getTeachingSchedule() List~Course~
        +submitGrade(Student student, Course course, String marks) void
    }

    class Role {
        <<enumeration>>
        ADMIN
        PROFESSOR
        STUDENT
    }

    %% Relationships and Connectors
    UniversitySystem "1" --> "1" User : Stores in Map
    UniversitySystem "1" --> "1" Course : Stores in Map

    User <|-- Student : Extends
    User <|-- Professor : Extends
    User ..> Role : Has Role

    Student "0..*" -- "0..*" Course : Many-to-Many Enrollment (Bidirectional)
    Course "0..*" -- "0..*" Student : Tracks Roster

    Course "0..*" --> "1" Professor : Mentored By
    Professor "1" --> "0..*" Course : Teaches (One-to-Many)

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🛠️ Features Implemented

1. Robust I/O Input Shielding

• Type Guarding: Custom validation interceptors catch input conversion bugs (such as typing characters into menu items expecting integers) via structured exception shielding.

• Buffer Cleaning: Gracefully empties out mismatched token entries to prevent terminal input lockups.

2. Administrator Controls

• Account Generation: Programmatic provisioning of sequential ID records for staff and student entities.

• Curriculum Mapping: Creation of distinct courses mapped to active instructional personnel indices.

3. Faculty Utilities

• Roster Introspection: Real-time visibility into dynamic course student registration sequences.

• Evaluation Engine: Direct modification capabilities for assigning continuous evaluation records or letter grades to registered users.

4. Student Portals

• Capacity-Aware Registration: Real-time query options for registration lists that actively respect maximum seat restrictions.

• Transcript Compilation: Instant calculation and summary view of active enrollments alongside finalized evaluations.

🗃️ Project Structure

university-management-system
    ├── src
    │   ├── com
    │   │   └── university
    │   │       └── service
    │   │           ├── AdminServiceTest.java
    │   │           ├── ProfessorServiceTest.java
    │   │           ├── StudentServiceTest.java
    │   │           └── UniversityRegistryTest.java
    │   └── main
    │       └── java
    │           └── com
    │               └── university
    │                   ├── cli
    │                   │   ├── ConsoleManager.java
    │                   │   └── SystemFunctions.java
    │                   ├── Main.java
    │                   ├── model
    │                   │   ├── Admin.java
    │                   │   ├── Course.java
    │                   │   ├── Professor.java
    │                   │   ├── Role.java
    │                   │   ├── Student.java
    │                   │   └── User.java
    │                   └── registry
    │                       └── RegistrySystem.java
    └── university-management-system.iml