added valid or empty semantics

1 files changed, 10 insertions, 2 deletions

diff --git a/src/main/scala/xyz/driver/core/database/Converters.scala b/src/main/scala/xyz/driver/core/database/Converters.scala
index 6faf627..1a40c45 100644
--- a/src/main/scala/xyz/driver/core/database/Converters.scala
+++ b/src/main/scala/xyz/driver/core/database/Converters.scala
@@ -4,6 +4,9 @@ import xyz.driver.core.rest.errors.DatabaseException
 
 import scala.reflect.ClassTag
 
+/**
+  * Helper methods for converting between table rows and Scala objects
+  */
 trait Converters {
   def fromStringOrThrow[ADT](entityStr: String, mapper: (String => Option[ADT]), entityName: String): ADT =
     mapper(entityStr).getOrElse(throw DatabaseException(s"Invalid $entityName in database: $entityStr"))
@@ -11,8 +14,13 @@ trait Converters {
   def expectValid[ADT](mapper: String => Option[ADT], query: String)(implicit ct: ClassTag[ADT]): ADT =
     fromStringOrThrow[ADT](query, mapper, ct.toString())
 
-  def expectExistsAndValid[ADT](mapper: String => Option[ADT], query: Option[String], contextMsg: String = "")(
-      implicit ct: ClassTag[ADT]): ADT = {
+  def expectExistsAndValid[ADT](mapper: String => Option[ADT], query: Option[String], contextMsg: String = "")
+                               (implicit ct: ClassTag[ADT]): ADT = {
     expectValid[ADT](mapper, query.getOrElse(throw DatabaseException(contextMsg)))
   }
+
+  def expectValidOrEmpty[ADT](mapper: String => Option[ADT], query: Option[String], contextMsg: String = "")
+                             (implicit ct: ClassTag[ADT]): Option[ADT] = {
+    if (query.isDefined) Some(expectValid[ADT](mapper, query.get)) else None
+  }
 }