Design a Payment Processor
Strategy PatternState PatternCommand PatternIdempotencyRetry Logic
Design a payment processor system that supports multiple payment methods (credit card, PayPal, bank transfer), manages transaction states, ensures idempotency to prevent duplicate charges, and implements retry logic for handling transient failures. The system should handle concurrent transactions safely and be extensible for adding new payment methods.
What You'll Build
- The system should support multiple payment methods including credit cards, PayPal, and bank transfers, with the ability to easily add new payment methods.
- Each transaction must have a state (PENDING, PROCESSING, COMPLETED, FAILED, REFUNDED) and transition between states appropriately.
- The system must ensure idempotency - processing the same payment request multiple times should not result in duplicate charges. Each transaction must have a unique idempotency key.
- The system should implement retry logic for transient failures, automatically retrying failed transactions with exponential backoff up to a maximum number of attempts.
- The system must handle concurrent transactions safely, ensuring thread safety and preventing race conditions.
- ...and more
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