1 files changed, 19 insertions, 0 deletions
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/result/NullId.java b/container-search/src/main/java/com/yahoo/search/grouping/result/NullId.java
new file mode 100644
index 00000000000..a6473837c76
--- /dev/null
+++ b/container-search/src/main/java/com/yahoo/search/grouping/result/NullId.java
@@ -0,0 +1,19 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.search.grouping.result;
+
+/**
+ * This class is in {@link Group} instances where the identifying expression evaluated to null. For example, hits that
+ * fall outside the buckets of a {@link com.yahoo.search.grouping.request.PredefinedFunction} are added to an
+ * auto-generated group with this id.
+ *
+ * @author <a href="mailto:simon@yahoo-inc.com">Simon Thoresen</a>
+ */
+public class NullId extends GroupId {
+
+    /**
+     * Constructs a new instance of this class.
+     */
+    public NullId() {
+        super("null");
+    }
+}