1 files changed, 45 insertions, 0 deletions
diff --git a/pkg/domain/entities/set.go b/pkg/domain/entities/set.go
new file mode 100644
index 000000000..c8d6cb1a9
--- /dev/null
+++ b/pkg/domain/entities/set.go
@@ -0,0 +1,45 @@
+package entities
+
+import (
+	"strings"
+)
+
+type stringSet struct {
+	m map[string]struct{}
+}
+
+func NewStringSet(elem ...string) *stringSet {
+	s := &stringSet{}
+	s.m = make(map[string]struct{}, len(elem))
+	for _, e := range elem {
+		s.Add(e)
+	}
+	return s
+}
+
+func (s *stringSet) Add(elem string) {
+	s.m[elem] = struct{}{}
+}
+
+func (s *stringSet) Remove(elem string) {
+	delete(s.m, elem)
+}
+
+func (s *stringSet) Contains(elem string) bool {
+	_, ok := s.m[elem]
+	return ok
+}
+
+func (s *stringSet) Elements() []string {
+	keys := make([]string, len(s.m))
+	i := 0
+	for k := range s.m {
+		keys[i] = k
+		i++
+	}
+	return keys
+}
+
+func (s *stringSet) String() string {
+	return strings.Join(s.Elements(), ", ")
+}