Add ExpiringMemoryCache implementation #1
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@ -0,0 +1,29 @@
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---
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global-variables:
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gradle-image: &gradle-image gradle:7.1-jdk11
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kind: pipeline
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name: default
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type: docker
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steps:
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- name: gradle-test
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image: *gradle-image
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commands:
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- gradle test
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when:
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branch: develop
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- name: publish
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image: *gradle-image
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environment:
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MAVEN_REPOSITORY_URL: https://archiva.fyloz.dev/repository/internal/
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MAVEN_REPOSITORY_USERNAME:
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from_secret: maven_repository_username
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MAVEN_REPOSITORY_PASSWORD:
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from_secret: maven_repository_password
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commands:
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- gradle publish -Pversion=${DRONE_TAG}
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when:
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event:
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- tag
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@ -1,8 +1,8 @@
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group = "dev.fyloz"
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group = "dev.fyloz"
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version = "1.0"
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plugins {
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plugins {
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id("org.jetbrains.kotlin.jvm") version "1.6.10"
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id("org.jetbrains.kotlin.jvm") version "1.6.10"
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id("maven-publish")
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}
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}
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repositories {
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repositories {
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@ -21,6 +21,39 @@ dependencies {
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testImplementation("io.mockk:mockk:1.12.2")
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testImplementation("io.mockk:mockk:1.12.2")
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}
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}
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tasks.withType<Test> {
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publishing {
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useJUnitPlatform()
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publications {
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create<MavenPublication>("memory-cache") {
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from(components["kotlin"])
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}
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}
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repositories {
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maven {
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val repoUrl = System.getenv("MAVEN_REPOSITORY_URL")
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val repoUsername = System.getenv("MAVEN_REPOSITORY_USERNAME")
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val repoPassword = System.getenv("MAVEN_REPOSITORY_PASSWORD")
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val repoName = System.getenv("MAVEN_REPOSITORY_NAME") ?: "Archiva"
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if (repoUrl != null && repoUsername != null && repoPassword != null) {
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url = uri(repoUrl)
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name = repoName
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credentials {
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username = repoUsername
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password = repoPassword
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}
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} else {
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print("Some maven repository credentials were not configured, publishing is not configured")
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}
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}
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}
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}
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tasks.test {
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useJUnitPlatform()
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testLogging {
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events("failed")
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}
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}
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}
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@ -1 +1,2 @@
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kotlin.code.style=official
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kotlin.code.style=official
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version=dev
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@ -0,0 +1,129 @@
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package dev.fyloz.memorycache
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import dev.fyloz.memorycache.utils.removeFirst
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import java.time.Instant
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import java.util.*
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/**
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* A key-value memory cache allowing for expiring keys.
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*
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* The key's expiration can be setup with two methods:
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* - After a number of access to the cache
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* - After a duration
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*
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* Either methods can be used, or both. But at least one need to be configured.
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* Note that using a single method is more optimized, since the keys can be sorted easily.
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*
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* For both methods, the lifetime of the key will be renewed after it has been set or accessed.
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*
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* @param K The type of the keys.
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* @param V The type of the values.
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* @property maxAccessCount The number of access to the cache before a key expires.
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* @property maxLifetimeSeconds The duration of a key before its expiration in seconds.
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*/
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class ExpiringMemoryCache<K, V>(
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private val maxAccessCount: Long = -1,
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private val maxLifetimeSeconds: Long = -1
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) : BaseMemoryCache<K, V>() {
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private val keys: TreeSet<ExpiringKey<K>>
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private var accessCount = 0L
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private val maxLifetimeMillis = maxLifetimeSeconds * 1000
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private val expireByAccessCount: Boolean = maxAccessCount > 0
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private val expireByAccessTime: Boolean = maxLifetimeSeconds > 0
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init {
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// Determine the correct key comparator to use
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val keysComparator: Comparator<ExpiringKey<*>> = if (expireByAccessCount) {
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ExpiringKey.accessCountComparator
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} else if (expireByAccessTime) {
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ExpiringKey.timeComparator
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} else {
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throw InvalidExpiringCacheOptionsException()
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}
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keys = TreeSet(keysComparator)
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}
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override fun get(key: K): V? {
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accessCount++
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cleanup()
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renewKey(key)
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return super.get(key)
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}
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override fun set(key: K, value: V) {
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super.set(key, value)
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renewKey(key)
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}
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override fun remove(key: K) {
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super.remove(key)
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keys.removeFirst { it.key == key }
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}
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override fun clear() {
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super.clear()
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keys.clear()
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accessCount = 0
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}
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private fun renewKey(key: K) {
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keys.removeFirst { it.key == key }
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keys.add(getNewExpiringKey(key))
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}
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private fun cleanup() {
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with(keys.iterator()) {
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while (hasNext()) {
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val expiringKey = next()
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if (expireByAccessCount) {
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if (accessCount - expiringKey.lastAccessCount > maxAccessCount) {
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removeExpiringKey(expiringKey)
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} else if (!expireByAccessTime) {
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break // Keys are sorted, so if this key is not expired, the next ones are not
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}
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}
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if (expireByAccessTime) {
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if (getCurrentTime() - expiringKey.lastAccessMillis > maxLifetimeMillis) {
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removeExpiringKey(expiringKey)
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} else if (!expireByAccessCount) {
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break
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}
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}
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}
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}
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}
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private fun MutableIterator<ExpiringKey<K>>.removeExpiringKey(expiringKey: ExpiringKey<K>) {
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remove()
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super.remove(expiringKey.key)
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}
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private fun getNewExpiringKey(key: K) =
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ExpiringKey(key, accessCount, getCurrentTime())
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private fun getCurrentTime() =
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Instant.now().toEpochMilli()
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}
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private data class ExpiringKey<K>(val key: K, var lastAccessCount: Long, var lastAccessMillis: Long) {
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companion object {
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internal val accessCountComparator: Comparator<ExpiringKey<*>> =
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Comparator.comparingLong<ExpiringKey<*>> { it.lastAccessCount }
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.thenComparingLong { it.lastAccessMillis }
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.thenComparingInt { it.key.hashCode() }
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internal val timeComparator: Comparator<ExpiringKey<*>> =
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Comparator.comparingLong<ExpiringKey<*>> { it.lastAccessMillis }
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.thenComparingLong { it.lastAccessCount }
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.thenComparingInt { it.key.hashCode() }
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}
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}
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internal class InvalidExpiringCacheOptionsException :
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RuntimeException("An expiration cache must have at least one expiration method configured")
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@ -0,0 +1,41 @@
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package dev.fyloz.memorycache.utils
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/**
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* Removes the first element matching the given [predicate] in this [MutableIterable].
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* Returns true if any element was removed.
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*/
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inline fun <T> MutableIterable<T>.removeFirst(predicate: (T) -> Boolean): Boolean {
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with(iterator()) {
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while (hasNext()) {
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if (predicate(next())) {
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remove()
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return true
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}
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}
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}
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return false
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}
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/** Gets the nth item in this [Iterable]. */
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inline fun <T> Iterable<T>.nth(n: Int, predicate: (T) -> Boolean): T? {
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var matches = 0
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for (item in this) {
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if (!predicate(item)) {
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continue
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}
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matches++
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if (matches == n) {
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return item
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}
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}
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return null
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}
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/** Is this [Int] is even or not. */
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val Int.isEven: Boolean
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get() = this % 2 == 0
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@ -0,0 +1,98 @@
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package dev.fyloz.memorycache
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import io.kotest.assertions.throwables.shouldThrow
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import io.kotest.core.spec.style.ShouldSpec
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import io.kotest.matchers.shouldBe
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import kotlinx.coroutines.Dispatchers
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import kotlinx.coroutines.withContext
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class ExpiringMemoryCacheTest : ShouldSpec({
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context("expiration by access count") {
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val maxAccessCount = 5L
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val cache = ExpiringMemoryCache<Int, String>(maxAccessCount = maxAccessCount)
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val accessedKey = 0
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val expiringKey = Int.MAX_VALUE
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should("removes expired keys") {
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// Arrange
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cache[accessedKey] = accessedKey.toString()
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cache[expiringKey] = expiringKey.toString()
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// Act
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for (i in 0..maxAccessCount) {
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cache[accessedKey]
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}
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// Assert
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val containsUnusedKey = expiringKey in cache
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containsUnusedKey shouldBe false
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}
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should("renew keys on access") {
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// Arrange
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cache[accessedKey] = accessedKey.toString()
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cache[expiringKey] = expiringKey.toString()
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for (i in 0 until maxAccessCount - 1) {
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cache[accessedKey]
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}
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// Act
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cache[expiringKey]
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// Assert
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val containsUnusedKey = expiringKey in cache
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containsUnusedKey shouldBe true
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}
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}
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|
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context("expiration by access time") {
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val maxLifetimeSeconds = 2L
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val cache = ExpiringMemoryCache<Int, String>(maxLifetimeSeconds = maxLifetimeSeconds)
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|
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val key = Int.MAX_VALUE
|
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|
||||||
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suspend fun wait(seconds: Long) =
|
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withContext(Dispatchers.IO) {
|
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Thread.sleep(seconds * 1000)
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}
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|
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should("removes expired keys") {
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// Arrange
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cache[key] = key.toString()
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|
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// Act
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wait(maxLifetimeSeconds)
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cache[key]
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|
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// Assert
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val containsKey = key in cache
|
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containsKey shouldBe false
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}
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|
||||||
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should("renew keys on access") {
|
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// Arrange
|
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cache[key] = key.toString()
|
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|
|
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// Act
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wait(maxLifetimeSeconds / 2)
|
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cache[key] // Access key before expiration
|
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wait(maxLifetimeSeconds / 2)
|
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cache[key]
|
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|
|
||||||
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// Assert
|
||||||
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val containsKey = key in cache
|
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|
containsKey shouldBe true
|
||||||
|
}
|
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}
|
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|
|
||||||
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context("no expiration method defined") {
|
||||||
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should("throws InvalidExpiringCacheOptionsException") {
|
||||||
|
// Arrange
|
||||||
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// Act
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||||||
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// Assert
|
||||||
|
shouldThrow<InvalidExpiringCacheOptionsException> { ExpiringMemoryCache<Int, String>() }
|
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|
}
|
||||||
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}
|
||||||
|
})
|
|
@ -0,0 +1,42 @@
|
||||||
|
package dev.fyloz.memorycache.utils
|
||||||
|
|
||||||
|
import io.kotest.core.spec.style.ShouldSpec
|
||||||
|
import io.kotest.matchers.shouldBe
|
||||||
|
|
||||||
|
class CollectionsTest : ShouldSpec({
|
||||||
|
context("removeFirst") {
|
||||||
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val collection = setOf(1, 2, 3, 4, 5)
|
||||||
|
|
||||||
|
fun getMutableCollection() = mutableSetOf(*collection.toTypedArray())
|
||||||
|
|
||||||
|
var mutableCollection = getMutableCollection()
|
||||||
|
|
||||||
|
beforeEach {
|
||||||
|
mutableCollection = getMutableCollection()
|
||||||
|
}
|
||||||
|
|
||||||
|
should("remove first item matching predicate from collection") {
|
||||||
|
// Arrange
|
||||||
|
val firstEvenItem = mutableCollection.first { it.isEven }
|
||||||
|
|
||||||
|
// Act
|
||||||
|
mutableCollection.removeFirst { it.isEven }
|
||||||
|
|
||||||
|
// Assert
|
||||||
|
val contains = firstEvenItem in mutableCollection
|
||||||
|
contains shouldBe false
|
||||||
|
}
|
||||||
|
|
||||||
|
should("does not remove second item matching predicate from collection") {
|
||||||
|
// Arrange
|
||||||
|
val secondEvenItem = mutableCollection.nth(2) { it.isEven }
|
||||||
|
|
||||||
|
// Act
|
||||||
|
mutableCollection.removeFirst { it.isEven }
|
||||||
|
|
||||||
|
// Assert
|
||||||
|
val contains = secondEvenItem in mutableCollection
|
||||||
|
contains shouldBe true
|
||||||
|
}
|
||||||
|
}
|
||||||
|
})
|
Loading…
Reference in New Issue