diff --git a/core/src/main/scala/lightdb/Collection.scala b/core/src/main/scala/lightdb/Collection.scala
index d11c8e3e..145cb31b 100644
--- a/core/src/main/scala/lightdb/Collection.scala
+++ b/core/src/main/scala/lightdb/Collection.scala
@@ -8,13 +8,6 @@ import fabric.rw.RW
 import io.chrisdavenport.keysemaphore.KeySemaphore
 import lightdb.index._
 
-sealed trait DocLock[D <: Document[D]] extends Any
-
-object DocLock {
-  case class Set[D <: Document[D]](id: Id[D]) extends DocLock[D]
-  class Empty[D <: Document[D]] extends DocLock[D]
-}
-
 abstract class Collection[D <: Document[D]](val collectionName: String,
                                             protected[lightdb] val db: LightDB,
                                             val autoCommit: Boolean = false,
diff --git a/core/src/main/scala/lightdb/DocLock.scala b/core/src/main/scala/lightdb/DocLock.scala
new file mode 100644
index 00000000..d2772ee9
--- /dev/null
+++ b/core/src/main/scala/lightdb/DocLock.scala
@@ -0,0 +1,8 @@
+package lightdb
+
+sealed trait DocLock[D <: Document[D]] extends Any
+
+object DocLock {
+  case class Set[D <: Document[D]](id: Id[D]) extends DocLock[D]
+  class Empty[D <: Document[D]] extends DocLock[D]
+}
\ No newline at end of file