1 files changed, 27 insertions, 0 deletions
diff --git a/src/main/java/org/zwobble/couscous/util/InsertionOrderSet.java b/src/main/java/org/zwobble/couscous/util/InsertionOrderSet.java
new file mode 100644
index 0000000..4272add
--- /dev/null
+++ b/src/main/java/org/zwobble/couscous/util/InsertionOrderSet.java
@@ -0,0 +1,27 @@
+package org.zwobble.couscous.util;
+
+import java.util.Iterator;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
+
+public interface InsertionOrderSet<T> extends Iterable<T> {
+    static <T> InsertionOrderSet<T> copyOf(Iterable<T> iterable) {
+        List<T> list = StreamSupport.stream(iterable.spliterator(), false)
+            .distinct()
+            .collect(Collectors.toList());
+        return new InsertionOrderSet<T>() {
+            @Override
+            public List<T> asList() {
+                return list;
+            }
+
+            @Override
+            public Iterator<T> iterator() {
+                return list.iterator();
+            }
+        };
+    }
+
+    List<T> asList();
+}