1 files changed, 10 insertions, 4 deletions
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingExpression.java b/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingExpression.java
index 2f7691156e5..ad97f5519ee 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingExpression.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingExpression.java
@@ -15,10 +15,14 @@ public abstract class GroupingExpression extends GroupingNode {
 
     private Integer level = null;
 
-    protected GroupingExpression(String image) {
-        super(image);
+    protected GroupingExpression(String image, String label, Integer level) {
+        super(image, label);
+        this.level = level;
     }
 
+    /** Returns a deep copy of this */
+    public abstract GroupingExpression copy();
+
     /**
      * Resolves the conceptual level of this expression. This level represents the type of data that is consumed by this
      * expression, where level 0 is a single hit, level 1 is a group, level 2 is a list of groups, and so forth. This
@@ -39,8 +43,8 @@ public abstract class GroupingExpression extends GroupingNode {
     /**
      * Returns the conceptual level of this expression.
      *
-     * @return The level.
-     * @throws IllegalArgumentException Thrown if the level of this expression has not been resolved.
+     * @return the level.
+     * @throws IllegalArgumentException thrown if the level of this expression has not been resolved.
      * @see #resolveLevel(int)
      */
     public int getLevel() {
@@ -50,6 +54,8 @@ public abstract class GroupingExpression extends GroupingNode {
         return level;
     }
 
+    protected final Integer getLevelOrNull() { return level; }
+
     /**
      * Recursively calls {@link ExpressionVisitor#visitExpression(GroupingExpression)} for this expression and all of
      * its argument expressions.