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OOD - Coffee Shop Order Management System

mediumLast edited: January 1, 2026

1. Problem Statement
2. System Requirements
3. Use Case Diagram
4. Class Diagram
5. Activity Diagrams
Order Placement Workflow
Order Preparation Workflow
6. Java Implementation
7. Design Patterns Applied
1. Producer-Consumer Pattern
2. Observer Pattern (Notification Service)
3. Builder Pattern (Order Creation)
4. Singleton Pattern (NotificationService)
5. Command Pattern (Future Enhancement)
6. State Pattern (Order Status)
8. Key Design Decisions
Decision 1: BlockingQueue for Thread Safety
Decision 2: Immutable Order ID Generation
Decision 3: Barista as Runnable
Decision 4: Synchron ized Status Updates
Decision 5: Separate OrderItem from MenuItem
Decision 6: Observer Pattern for Notifications
Decision 7: Simple Payment Model
Decision 8: No Order Cancellation
Decision 9: Unbounded Queue
Decision 10: In-Memory Storage

Related Tags

ood-object-oriented-design coffee-shop order-queue producer-consumer

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