diff --git a/gradle.properties b/gradle.properties
index 9d8f0ee..51e3b6d 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -4,7 +4,7 @@ kotlin.code.style=official
 specifyKotlinAsDependency=false
 
 projectGroup=ru.dbotthepony.kommons
-projectVersion=1.7.4
+projectVersion=1.7.5
 
 guavaDepVersion=33.0.0
 gsonDepVersion=2.8.9
diff --git a/src/main/kotlin/ru/dbotthepony/kommons/collect/CollectionUtils.kt b/src/main/kotlin/ru/dbotthepony/kommons/collect/CollectionUtils.kt
index 649ce25..fda0424 100644
--- a/src/main/kotlin/ru/dbotthepony/kommons/collect/CollectionUtils.kt
+++ b/src/main/kotlin/ru/dbotthepony/kommons/collect/CollectionUtils.kt
@@ -1,7 +1,9 @@
 package ru.dbotthepony.kommons.collect
 
+import ru.dbotthepony.kommons.core.KOptional
 import java.lang.ref.Reference
 import java.util.*
+import java.util.concurrent.CompletableFuture
 import java.util.stream.Stream
 import java.util.stream.StreamSupport
 
@@ -17,8 +19,8 @@ inline fun <reified T> Stream<*>.filterIsInstance(): Stream<T> {
 	return filter { it is T } as Stream<T>
 }
 
-inline fun <T> MutableList<out Reference<out T>>.forValidRefs(fn: (T) -> Unit) {
-	val iterator = listIterator()
+inline fun <T> MutableIterable<Reference<out T>>.forValidRefs(fn: (T) -> Unit) {
+	val iterator = iterator()
 
 	for (value in iterator) {
 		val get = value.get()
@@ -31,8 +33,8 @@ inline fun <T> MutableList<out Reference<out T>>.forValidRefs(fn: (T) -> Unit) {
 	}
 }
 
-inline fun <T> MutableList<out Reference<out T>>.forValidRefsBreak(fn: (T) -> Boolean) {
-	val iterator = listIterator()
+inline fun <T> MutableIterable<Reference<out T>>.forValidRefsBreak(fn: (T) -> Boolean) {
+	val iterator = iterator()
 
 	for (value in iterator) {
 		val get = value.get()
@@ -47,6 +49,21 @@ inline fun <T> MutableList<out Reference<out T>>.forValidRefsBreak(fn: (T) -> Bo
 	}
 }
 
+fun <S, T> chainOptionalFutures(source: Iterable<S>, mapper: (S) -> CompletableFuture<KOptional<T>>): CompletableFuture<KOptional<T>> {
+	val itr = source.iterator()
+
+	if (itr.hasNext()) {
+		var future = mapper.invoke(itr.next())
+
+		for (v in itr)
+			future = future.thenCompose { if (it.isPresent) CompletableFuture.completedFuture(it) else mapper.invoke(v) }
+
+		return future
+	}
+
+	return CompletableFuture.completedFuture(KOptional.empty())
+}
+
 fun <T> Stream<T>.asIterable(): Iterable<T> {
 	return object : Iterable<T> {
 		override fun iterator(): Iterator<T> {