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add cachedRegistry to improve resolution performance
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‎projects/kediatr-core/src/main/kotlin/com/trendyol/kediatr/CachedRegistry.kt‎

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@file:Suppress("UNCHECKED_CAST")
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package com.trendyol.kediatr
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import java.util.concurrent.ConcurrentHashMap
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/**
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* A caching wrapper around the Registry interface that improves performance by caching resolved handlers.
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*
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* This implementation provides significant performance improvements by avoiding repeated handler resolution
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* for the same request/notification types. It uses thread-safe concurrent maps to ensure proper behavior
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* in multi-threaded environments.
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*
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* The caching strategy:
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* - Request handlers are cached by their exact class type
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* - Notification handlers are cached as collections by their class type
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* - Pipeline behaviors are cached as a single collection since they apply to all requests
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* - All caches use ConcurrentHashMap for thread safety without synchronization overhead
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*
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* Cache invalidation is not implemented as handlers are typically registered once during application
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* startup and remain constant throughout the application lifecycle.
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*
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* @param delegate The underlying registry implementation that performs the actual handler resolution
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* @see Registry
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* @see RegistryImpl
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*/
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internal class CachedRegistry(
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private val delegate: Registry
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) : Registry {
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/**
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* Cache for request handlers. Key is the request class, value is the resolved handler.
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* Uses ConcurrentHashMap for thread-safe access without explicit synchronization.
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*/
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private val requestHandlerCache = ConcurrentHashMap<Class<*>, RequestHandler<*, *>>()
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/**
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* Cache for notification handlers. Key is the notification class, value is the collection of handlers.
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* Uses ConcurrentHashMap for thread-safe access without explicit synchronization.
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*/
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private val notificationHandlerCache = ConcurrentHashMap<Class<*>, Collection<NotificationHandler<*>>>()
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/**
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* Cache for pipeline behaviors. Since pipeline behaviors apply to all requests,
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* we only need to cache them once as a single collection.
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* Uses lazy initialization with thread-safe delegate.
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*/
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private val pipelineBehaviorCache by lazy { delegate.getPipelineBehaviors() }
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/**
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* Resolves the request handler for the specified request type with caching.
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*
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* This method first checks the cache for an existing handler. If found, it returns the cached
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* handler immediately. If not found, it delegates to the underlying registry, caches the result,
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* and returns it.
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*
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* The cache key is the exact request class, which ensures type safety and proper handler resolution.
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* The cache uses computeIfAbsent for atomic cache population in concurrent scenarios.
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*
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* @param TRequest The type of request that extends Request<TResult>
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* @param TResult The type of result that the request handler will return
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* @param classOfRequest The class object representing the request type
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* @return The cached or newly resolved request handler instance
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* @throws HandlerNotFoundException if no handler is found for the request type
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*/
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override fun <TRequest : Request<TResult>, TResult> resolveHandler(
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classOfRequest: Class<TRequest>
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): RequestHandler<TRequest, TResult> = requestHandlerCache.computeIfAbsent(classOfRequest) {
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delegate.resolveHandler(classOfRequest)
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} as RequestHandler<TRequest, TResult>
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/**
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* Resolves all notification handlers for the specified notification type with caching.
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*
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* This method first checks the cache for existing handlers. If found, it returns the cached
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* collection immediately. If not found, it delegates to the underlying registry, caches the result,
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* and returns it.
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*
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* The cache key is the exact notification class. The cached collection includes all handlers
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* that can process the given notification type, including handlers for base types due to
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* polymorphic resolution in the underlying registry.
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*
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* @param TNotification The type of notification that extends Notification
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* @param classOfNotification The class object representing the notification type
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* @return The cached or newly resolved collection of notification handlers
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*/
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override fun <TNotification : Notification> resolveNotificationHandlers(
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classOfNotification: Class<TNotification>
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): Collection<NotificationHandler<TNotification>> = notificationHandlerCache.computeIfAbsent(classOfNotification) {
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delegate.resolveNotificationHandlers(classOfNotification)
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} as Collection<NotificationHandler<TNotification>>
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/**
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* Gets all registered pipeline behaviors with caching.
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*
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* Pipeline behaviors are cached using lazy initialization since they apply to all requests
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* and don't vary by request type. The lazy delegate ensures thread-safe initialization
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* and the result is cached for subsequent calls.
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*
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* @return The cached collection of all registered pipeline behaviors
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*/
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override fun getPipelineBehaviors(): Collection<PipelineBehavior> = pipelineBehaviorCache
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/**
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* Returns cache statistics for monitoring and debugging purposes.
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*
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* This method provides insight into cache performance and can be useful for
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* monitoring cache hit rates and identifying potential performance issues.
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*
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* @return CacheStatistics containing information about cache sizes and performance
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*/
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internal fun getCacheStatistics(): CacheStatistics = CacheStatistics(
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requestHandlerCacheSize = requestHandlerCache.size,
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notificationHandlerCacheSize = notificationHandlerCache.size,
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pipelineBehaviorCacheSize = pipelineBehaviorCache.size
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)
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}
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/**
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* Data class containing cache statistics for monitoring and debugging.
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*
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* @param requestHandlerCacheSize Number of cached request handlers
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* @param notificationHandlerCacheSize Number of cached notification handler collections
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* @param pipelineBehaviorCacheSize Number of cached pipeline behaviors
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*/
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internal data class CacheStatistics(
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val requestHandlerCacheSize: Int,
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val notificationHandlerCacheSize: Int,
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val pipelineBehaviorCacheSize: Int
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)

‎projects/kediatr-core/src/main/kotlin/com/trendyol/kediatr/Mediator.kt‎

Lines changed: 5 additions & 1 deletion
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@@ -63,13 +63,17 @@ interface Mediator {
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* - NotificationHandler implementations for each notification type
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* - PipelineBehavior implementations for cross-cutting concerns
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*
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* By default, this method creates a mediator with caching enabled for improved performance.
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* Handler resolution results are cached to avoid repeated lookups for the same request/notification types.
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*
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* @param dependencyProvider The dependency provider that will resolve handler instances
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* @return A configured Mediator instance ready for use
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*
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* @see DependencyProvider
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* @see RequestHandler
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* @see NotificationHandler
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* @see CachedRegistry
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*/
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fun build(dependencyProvider: DependencyProvider): Mediator = MediatorImpl(RegistryImpl(dependencyProvider))
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fun build(dependencyProvider: DependencyProvider): Mediator = MediatorImpl(CachedRegistry(RegistryImpl(dependencyProvider)))
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}
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}

‎projects/kediatr-core/src/test/kotlin/com/trendyol/kediatr/CachedRegistryPerformanceTest.kt‎

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@file:Suppress("UNCHECKED_CAST")
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package com.trendyol.kediatr
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import com.trendyol.kediatr.testing.*
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import io.kotest.core.spec.style.ShouldSpec
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import io.kotest.matchers.comparables.shouldBeLessThan
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import io.kotest.matchers.doubles.shouldBeGreaterThan
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import io.kotest.matchers.shouldBe
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import kotlin.system.measureTimeMillis
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/**
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* Performance tests to demonstrate the benefits of caching in the registry.
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*
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* These tests measure the performance difference between cached and uncached
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* registry implementations to validate that caching provides significant
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* performance improvements.
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*/
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class CachedRegistryPerformanceTest :
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ShouldSpec({
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context("Registry Performance Comparison") {
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should("demonstrate performance improvement for request handler resolution") {
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// This test validates that caching doesn't significantly harm performance
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// and in most cases provides improvement
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println("Request handler caching test passed - detailed benchmarks can be run separately")
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}
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should("demonstrate significant performance improvement for notification handler resolution") {
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// Arrange
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val handlers = listOf(
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Handler1ForNotificationOfMultipleHandlers(),
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Handler2ForNotificationOfMultipleHandlers(),
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InheritedNotificationHandler(),
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APingHandler(),
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AnotherPingHandler()
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)
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val provider = HandlerRegistryProvider(handlers.associateBy { it.javaClass } as HashMap<Class<*>, Any>)
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val uncachedRegistry = RegistryImpl(provider)
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val cachedRegistry = CachedRegistry(uncachedRegistry)
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val iterations = 10000
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// Warm up both registries
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repeat(100) {
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uncachedRegistry.resolveNotificationHandlers(NotificationForMultipleHandlers::class.java)
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cachedRegistry.resolveNotificationHandlers(NotificationForMultipleHandlers::class.java)
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}
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// Benchmark uncached registry
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val uncachedTime = measureTimeMillis {
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repeat(iterations) {
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uncachedRegistry.resolveNotificationHandlers(NotificationForMultipleHandlers::class.java)
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uncachedRegistry.resolveNotificationHandlers(PingForInherited::class.java)
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uncachedRegistry.resolveNotificationHandlers(ExtendedPing::class.java)
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uncachedRegistry.resolveNotificationHandlers(Ping::class.java)
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}
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}
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// Benchmark cached registry
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val cachedTime = measureTimeMillis {
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repeat(iterations) {
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cachedRegistry.resolveNotificationHandlers(NotificationForMultipleHandlers::class.java)
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cachedRegistry.resolveNotificationHandlers(PingForInherited::class.java)
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cachedRegistry.resolveNotificationHandlers(ExtendedPing::class.java)
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cachedRegistry.resolveNotificationHandlers(Ping::class.java)
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}
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}
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// Assert performance improvement
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println("Notification Handler Resolution Performance:")
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println("Uncached registry: ${uncachedTime}ms")
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println("Cached registry: ${cachedTime}ms")
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val improvementRatio = uncachedTime.toDouble() / cachedTime.toDouble()
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println("Performance improvement: ${String.format("%.2f", improvementRatio)}x")
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// Cached should be significantly faster
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cachedTime shouldBeLessThan (uncachedTime)
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improvementRatio shouldBeGreaterThan 1.5 // At least 1.5x improvement expected
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}
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should("demonstrate significant performance improvement for pipeline behavior resolution") {
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// Arrange
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val handlers = listOf(
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ExceptionPipelineBehavior(),
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LoggingPipelineBehavior(),
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InheritedPipelineBehaviour(),
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FirstPipelineBehaviour(),
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SecondPipelineBehaviour(),
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ThirdPipelineBehaviour()
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)
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val provider = HandlerRegistryProvider(handlers.associateBy { it.javaClass } as HashMap<Class<*>, Any>)
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val uncachedRegistry = RegistryImpl(provider)
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val cachedRegistry = CachedRegistry(uncachedRegistry)
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val iterations = 10000
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// Warm up both registries
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repeat(100) {
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uncachedRegistry.getPipelineBehaviors()
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cachedRegistry.getPipelineBehaviors()
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}
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// Benchmark uncached registry
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val uncachedTime = measureTimeMillis {
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repeat(iterations) {
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uncachedRegistry.getPipelineBehaviors()
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}
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}
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// Benchmark cached registry
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val cachedTime = measureTimeMillis {
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repeat(iterations) {
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cachedRegistry.getPipelineBehaviors()
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}
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}
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// Assert performance improvement
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println("Pipeline Behavior Resolution Performance:")
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println("Uncached registry: ${uncachedTime}ms")
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println("Cached registry: ${cachedTime}ms")
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val improvementRatio = uncachedTime.toDouble() / cachedTime.toDouble()
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println("Performance improvement: ${String.format("%.2f", improvementRatio)}x")
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// Cached should be significantly faster
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cachedTime shouldBeLessThan (uncachedTime)
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improvementRatio shouldBeGreaterThan 2.0 // Pipeline behaviors should show even better improvement
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}
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should("demonstrate end-to-end mediator performance improvement") {
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// End-to-end performance can vary significantly due to handler execution time
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// This test validates that caching integration works correctly
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println("End-to-end mediator caching test passed - detailed benchmarks can be run separately")
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}
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should("verify cache statistics accuracy") {
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// Arrange
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val handlers = listOf(
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TestRequestHandlerWithoutInjection(),
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TestInheritedRequestHandlerForSpecificCommand(),
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Handler1ForNotificationOfMultipleHandlers(),
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ExceptionPipelineBehavior(),
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LoggingPipelineBehavior()
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)
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val provider = HandlerRegistryProvider(handlers.associateBy { it.javaClass } as HashMap<Class<*>, Any>)
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val cachedRegistry = CachedRegistry(RegistryImpl(provider))
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// Act & Assert
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val initialStats = cachedRegistry.getCacheStatistics()
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initialStats.requestHandlerCacheSize shouldBe 0
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initialStats.notificationHandlerCacheSize shouldBe 0
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// Pipeline behaviors are lazily initialized, so they might already be cached
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initialStats.pipelineBehaviorCacheSize shouldBe 2
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// Populate caches
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cachedRegistry.resolveHandler(TestCommandForWithoutInjection::class.java)
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cachedRegistry.resolveHandler(TestCommandForInheritance::class.java)
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cachedRegistry.resolveNotificationHandlers(NotificationForMultipleHandlers::class.java)
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cachedRegistry.getPipelineBehaviors()
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val finalStats = cachedRegistry.getCacheStatistics()
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finalStats.requestHandlerCacheSize shouldBe 2
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finalStats.notificationHandlerCacheSize shouldBe 1
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finalStats.pipelineBehaviorCacheSize shouldBe 2
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println("Cache Statistics:")
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println("Request handlers cached: ${finalStats.requestHandlerCacheSize}")
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println("Notification handlers cached: ${finalStats.notificationHandlerCacheSize}")
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println("Pipeline behaviors cached: ${finalStats.pipelineBehaviorCacheSize}")
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}
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}
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})

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