Requirements

Imagine you're building a comment filtering system for Amazon product reviews. This system needs to efficiently and accurately filter comments based on various criteria such as profanity, spam, and adherence to community guidelines. The goal is to create a robust, extensible, and maintainable system that can adapt to evolving filtering requirements and increasing comment volume. Think about how you'd design the core components of such a system, focusing on object-oriented principles and design patterns. How would you make it flexible enough to add new filtering rules without modifying existing code? How would you handle potentially large volumes of comments efficiently? # Requirements ## Functional Requirements 1. **Comment Submission:** The system should accept comment submissions, including the comment text, author information (e.g., user ID), and product ID. 2. **Filtering Rules:** * Profanity filtering: Detect and flag comments containing profane language. This should support a configurable list of profane words and phrases. * Spam detection: Identify and flag comments that are likely spam, based on criteria such as excessive use of links, promotional content, or repetitive phrases. * Length restriction: Filter out comments that exceed a specified maximum length. * Content guideline compliance: Enforce specific content guidelines, such as restrictions on hate speech, personal attacks, or off-topic content. This can be rule-based. * Customizable rule sets: Allow different filtering rules to be applied to different product categories or user groups. 3. **Filtering Results:** The system should provide clear and actionable filtering results, indicating which rules were violated (if any) and providing a score or confidence level for each rule. 4. **Escalation:** Flag comments for manual review if filtering rules are violated above a certain threshold. 5. **Reporting/Metrics:** Provide metrics on the number of comments processed, the number of comments flagged by each rule, and the average processing time. 6. **Asynchronous Processing:** Handle comment filtering asynchronously to avoid blocking the comment submission process. 7. **Rule Management:** (Bonus) Allow administrators to add, remove, and update filtering rules dynamically. ## Non-Functional Requirements 1. **Thread Safety:** The system must be thread-safe to handle concurrent comment submissions and filtering operations. Consider how multiple threads will access and modify shared data structures like the rule sets. 2. **Extensibility:** The system must be easily extensible to support new filtering rules and criteria without modifying existing code. Consider using design patterns that promote loose coupling and open/closed principle. 3. **Modularity:** The system should be modular, with clear separation of concerns between different components (e.g., comment submission, rule management, filtering engine). 4. **Testability:** The system must be designed to be easily testable, with well-defined interfaces and dependencies. Consider using dependency injection to facilitate unit testing. 5. **Performance:** The filtering process should be efficient to handle a high volume of comment submissions. Consider optimizing the filtering algorithms and using appropriate data structures. Consider approaches for caching frequently used data (e.g., profanity lists) but keep the cache implementation details simple for this exercise (e.g., in-memory). 6. **Configurability:** The system should be configurable, allowing administrators to adjust filtering thresholds, rule sets, and other parameters. 7. **Maintainability:** The code should be well-documented, easy to understand, and follow coding best practices to ensure long-term maintainability. ## Core Entities 1. **Comment:** Represents a single comment submitted by a user. Attributes include text, author ID, product ID, submission timestamp, and filtering status. 2. **FilteringRule:** An abstract base class or interface for defining filtering rules. Subclasses could include `ProfanityFilter`, `SpamFilter`, `LengthFilter`, and `ContentGuidelineFilter`. 3. **FilteringEngine:** The core component responsible for applying filtering rules to comments and generating filtering results. 4. **FilteringResult:** Represents the outcome of applying a filtering rule to a comment. Includes information about whether the rule was violated, the severity of the violation, and any relevant details. 5. **RuleManager:** A component responsible for managing the set of active filtering rules. This may include adding, removing, and updating rules. 6. **CommentProcessor:** (Asynchronous) A component to actually queue the comment for processing and invoke the FilteringEngine.

Design Amazon comments filtering system

Requirements

Interview Simulation

Functional Requirements

💡 Interview Tip

Non-Functional Requirements

Core Entity Identification

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