Oracle Senior Software Engineer Technical Phone Interview Throttling Design

I recently had a phone screen with Oracle for a Senior Software Engineer role and was asked the following question: "In a first-person shooter (FPS) game, players trigger actions like shooting, reload

I recently had a phone screen with Oracle for a Senior Software Engineer role and was asked the following question: "In a first-person shooter (FPS) game, players trigger actions like shooting, reloading, or throwing grenades by pressing keys. During intense gameplay, players may press the same key repeatedly in a short period of time, which can lead to excessive event triggers." I was asked to design a throttling mechanism that ensures the same event type can only be triggered once within a given delay period. If the same event occurs again before the delay expires, it should be ignored. Each event type should be handled independently.

Example: delay = 5 events: [("shoot", 1), ("shoot", 2), ("reload", 3), ("shoot", 6)]

output: [true, false, true, true] This is the solution I came up with. Curious to know if there's a more optimal approach.

public class EventThrottler { private final Map lastTriggered; private final long delayMillis; public EventThrottler(long delayMillis) { this.delayMillis = delayMillis; this.lastTriggered = new HashMap<>(); } public boolean shouldTrigger(String eventType) { long currentTime = System.currentTimeMillis(); if (!lastTriggered.containsKey(eventType)) { lastTriggered.put(eventType, currentTime);

return true; } long lastTime = lastTriggered.get(eventType); if (currentTime - lastTime >= delayMillis) { lastTriggered.put(eventType, currentTime);

return true; }

return false; } }

One optimization I could think of is to use a ConcurrentHashMap instead of a regular HashMap for a multithreaded environment.