Merge pull request #1345 from lowzj/locator-add-select

feature: add Select api into SupernodeLocator

dfget/locator/locator.go

@@ -32,6 +32,10 @@ type SupernodeLocator interface {
 	// purpose. The current supernode should be set as this result.
 	Next() *Supernode
 
+	// Select chooses a supernode based on the giving key.
+	// It should not affect the result of method 'Get()'.
+	Select(key interface{}) *Supernode
+
 	// GetGroup returns the group with the giving name.
 	GetGroup(name string) *SupernodeGroup
 

dfget/locator/static_locator.go

@@ -96,6 +96,11 @@ func (s *StaticLocator) Next() *Supernode {
 	return s.Group.GetNode(s.inc())
 }
 
+func (s *StaticLocator) Select(key interface{}) *Supernode {
+	// unnecessary to implement this method
+	return nil
+}
+
 func (s *StaticLocator) GetGroup(name string) *SupernodeGroup {
 	if s.Group == nil || s.Group.Name != name {
 		return nil