Practice/Amazon/Design a Notification System

Design a Notification System

Object Oriented DesignMust

Problem

Design and implement a message delivery validation system that determines whether an incoming notification request meets all necessary criteria before it can be processed and sent to users.

Your system should implement a NotificationValidator class that checks notification requests against a set of business rules. A notification is represented as a dictionary/object containing various fields, and your validator must verify that all required fields are present and contain valid values.

The validation rules are:

• user_id: Must be present and must be a positive integer
• channel: Must be present and must be one of: "email", "sms", "push"
• content: Must be present and must be a non-empty string
• priority: Must be present and must be an integer between 1 and 5 (inclusive)

Requirements

1. Implement a NotificationValidator class with a method validate_notification that accepts a notification dictionary
2. Return True if the notification passes all validation rules, False otherwise
3. Handle missing fields gracefully (return False rather than raising exceptions)
4. Validate data types as well as values
5. The validator should be reusable across multiple validation calls

Constraints

• The notification dictionary may contain additional fields beyond the required ones (these should be ignored)
• Priority levels range from 1 (lowest) to 5 (highest)
• Content must have at least one character
• All inputs will be valid Python dictionaries/objects

Examples

Example 1:

Input: \{"user_id": 101, "channel": "email", "content": "Welcome!", "priority": 1\} Output: True Explanation: All required fields are present with valid values

Example 2:

Input: \{"user_id": 102, "channel": "telegram", "content": "Alert", "priority": 3\} Output: False Explanation: "telegram" is not a valid channel type

Example 3:

Input: \{"channel": "sms", "content": "Message", "priority": 2\} Output: False Explanation: Missing required field "user_id"

Example 4:

Input: \{"user_id": 103, "channel": "push", "content": "", "priority": 4\} Output: False Explanation: Content cannot be empty