← Akuna Capital Interview Insights
The spec looks simple but there are a lot of little branches to get right.
Start by clarifying requirements and defining the interface for CommsHandler and CommunicationException, then walk through the design of the abstract class and exception hierarchy, and finally discuss implementation details and edge cases. Emphasize clean separation of concerns, extensibility, and robust error handling.
Pro tip: Demonstrate awareness of thread safety and resource management, as these are critical in real-time communication systems like those at Akuna Capital. Mention how you would test the exception scenarios to ensure reliability.
Ask clarifying questions about expected behavior, such as whether connections are bidirectional, if multiple connections per caller are allowed, and what constitutes a 'busy' line. Confirm the need for thread safety and any performance constraints.
Design CommunicationException as a base class (likely extending std::exception or similar) with derived classes for specific errors like SelfConnectionException, BusyLineException, and InvalidHangupException. Ensure exceptions carry meaningful context.
Define pure virtual methods: connect(caller1, caller2), hangup(caller), and clearAll(). Specify preconditions and postconditions, and document which exceptions each method may throw.
Describe how you would implement the concrete class: maintain a mapping of active connections (e.g., a set of pairs or adjacency list), check for self-connection, busy lines, and invalid hangup attempts before modifying state. Use appropriate synchronization if needed.
Enumerate edge cases: connecting a caller to themselves, connecting when either caller is already in a call, hanging up a caller not in a call, clearing when no connections exist. Explain how you would test these scenarios, including unit tests for each exception.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.