import { OnModuleDestroy } from '@nestjs/common';
export interface EventHandlerMetadata {
    methodKey: string;
    targetCallback: Function;
    eventType: string;
    options?: any;
}
export declare class EventMetadataExplorer implements OnModuleDestroy {
    private readonly metadataScanner;
    private metadataCache;
    private readonly cacheTTL;
    private cacheHits;
    private cacheMisses;
    /**
     * Explore an instance for event handler methods with caching
     * Based on NestJS microservices ListenerMetadataExplorer pattern
     */
    explore(instance: any): EventHandlerMetadata[];
    /**
     * Explore a single method for event handler metadata
     */
    private exploreMethodMetadata;
    /**
     * Check if an instance has any event handlers with caching
     */
    hasEventHandlers(instance: any): boolean;
    /**
     * Get all event types that an instance handles with caching
     */
    getEventTypes(instance: any): string[];
    /**
     * Check if cached data is still valid
     */
    private isCacheValid;
    /**
     * Invalidate cache for a specific instance
     * Useful when instance methods are modified at runtime
     */
    invalidateCache(instance: any): void;
    /**
     * Clear all cached data
     * Useful for testing or when memory usage is a concern
     */
    clearCache(): void;
    /**
     * Get cache statistics for monitoring
     */
    getCacheStats(): {
        hits: number;
        misses: number;
        hitRate: number;
        cacheSize: number;
    };
    /**
     * Cleanup on module destroy
     */
    onModuleDestroy(): void;
    /**
     * Pre-warm cache for known instances
     * Useful for frequently accessed services
     */
    preWarmCache(instances: any[]): void;
}