diff --git a/integration/service/oasis/selectionstrategy/doc.go b/integration/service/oasis/selectionstrategy/doc.go
index 3a9e447065f..8676cbc077c 100644
--- a/integration/service/oasis/selectionstrategy/doc.go
+++ b/integration/service/oasis/selectionstrategy/doc.go
@@ -1,4 +1,11 @@
 /*
 Package selectionstrategy contains logic related with charge station selection related logic.
+It contains logic of:
+- detect wether destination is reachable or not
+- detect whether charge is needed or not
+- if charge for one time could reach destination, find best solution
+- best solution for multiple charge
+   + SearchAlongRoute(comment temporarily)
+   + ChargeStationBasedStrategy
 */
 package selectionstrategy
diff --git a/integration/service/oasis/selectionstrategy/resource_manager.go b/integration/service/oasis/selectionstrategy/resource_manager.go
index c74158adbbe..e97c104c4de 100644
--- a/integration/service/oasis/selectionstrategy/resource_manager.go
+++ b/integration/service/oasis/selectionstrategy/resource_manager.go
@@ -11,10 +11,13 @@ import (
 	"github.com/golang/glog"
 )
 
+// StaionSelectionStrategy defines enum of how to select optimal charge stations
 type StaionSelectionStrategy int
 
 const (
+	// FindChargeStaionsAlongRoute means first calculate a route, then try to find charge stations along the route when energy is low
 	FindChargeStaionsAlongRoute = StaionSelectionStrategy(iota) + 1
+	// ChargeStaionBasedRouting builds a graph of charge stations and apply shortest-path-algorithm on to it
 	ChargeStaionBasedRouting
 )