# Campus Event Management System - Updated Features

## Recent Improvements

### 1. Data Persistence
- **Events and registrations are now saved automatically** when the application closes
- **Data is loaded automatically** when the application starts
- Uses Java serialization to store data in `.ser` files
- All relevant classes implement `Serializable` interface

### 2. Enhanced Validation
- **Email validation**: Requires "@" symbol in email addresses
- **ID validation**: Ensures participant ID is numeric
- **Capacity checking**: Prevents registration when event capacity would be exceeded
- **Group size validation**: Checks available spots against requested group size

### 3. Improved Registration Logic
- **Group booking fees**: Base fee and optional services are multiplied by group size
- **Detailed billing**: Shows per-person costs and total costs for groups
- **Real-time updates**: Event table refreshes after registration to show updated counts

### 4. Fixed Update Functionality
- **Event updates now work properly**: Can modify event details while preserving registrations
- **Capacity validation**: Prevents reducing capacity below current registration count
- **Type consistency**: Prevents changing event type during updates

### 5. Better User Experience
- **Clear error messages** for all validation failures
- **Automatic table refresh** after operations
- **Proper form clearing** after successful operations
- **Capacity display** shows available spots vs. requested spots

### 6. Enhanced UML Diagrams
- **Improved visibility**: Regenerated diagrams with better text clarity
- **Complete coverage**: All relationships and patterns clearly shown
- **Professional quality**: Suitable for academic submission

## Technical Implementation Details

### Data Persistence Architecture
```
DataPersistence.java
├── saveEvents(List<Event>)
├── loadEvents()
├── saveRegistrations(List<Registration>)
└── loadRegistrations()
```

### Validation Flow
1. **Input Validation**: Check for empty fields
2. **Format Validation**: Email contains "@", ID is numeric
3. **Business Logic Validation**: Capacity checks, group size validation
4. **Success**: Process registration and save data

### Fee Calculation for Groups
- Base Fee: `event.getBaseFee() * groupSize`
- Optional Services: `service.getCost() * groupSize` for each service
- Discounts: Applied to total amount before final calculation

## Testing Scenarios Covered

### Data Persistence Testing
- ✅ Create events, close application, reopen - events persist
- ✅ Register participants, close application, reopen - registrations persist
- ✅ Registration counts maintained across sessions

### Validation Testing
- ✅ Email without "@" rejected
- ✅ Non-numeric ID rejected
- ✅ Registration exceeding capacity rejected
- ✅ Group size larger than available spots rejected

### Group Booking Testing
- ✅ Fees calculated correctly for multiple participants
- ✅ Optional services multiplied by group size
- ✅ Bill shows detailed breakdown per person and total

### Update Functionality Testing
- ✅ Event details can be modified
- ✅ Capacity cannot be reduced below current registrations
- ✅ Event type changes prevented (requires new event)

## File Structure Updates

### New Files Added
- `DataPersistence.java` - Handles saving/loading data

### Modified Files
- All entity classes now implement `Serializable`
- `EventManager.java` - Added data persistence methods
- `RegistrationManager.java` - Added data persistence methods
- `CampusEventManagementGUI.java` - Enhanced validation and UI updates
- `Registration.java` - Fixed group fee calculations

### Data Files (Created at Runtime)
- `events_data.ser` - Serialized events data
- `registrations_data.ser` - Serialized registrations data

## Quality Assurance

All improvements have been tested and verified to work correctly. The application now provides a robust, persistent, and user-friendly experience that meets all the original requirements plus the requested enhancements.

