Optimize CompoundName.first with 0 elements to return CompoundName.empty.

Optimize CompoundName.first with all elements to return self.

1 files changed, 2 insertions, 0 deletions

diff --git a/container-core/src/main/java/com/yahoo/processing/request/CompoundName.java b/container-core/src/main/java/com/yahoo/processing/request/CompoundName.java
index 5e52f8d8b37..6af4811fa1b 100644
--- a/container-core/src/main/java/com/yahoo/processing/request/CompoundName.java
+++ b/container-core/src/main/java/com/yahoo/processing/request/CompoundName.java
@@ -175,6 +175,8 @@ public final class CompoundName {
         if (compounds.size() < n)
             throw new IllegalArgumentException("Asked for the first " + n + " components but '" +
                                                this + "' only have " + compounds.size() + " components.");
+        if (compounds.size() == n) return this;
+        if (compounds.size() == 0) return empty;
         return new CompoundName(compounds.subList(0, n));
     }