(beam) branch master updated: Minor optimization for the common case of merging empty string sets. (#31803)

[robertwb]

This is an automated email from the ASF dual-hosted git repository.

robertwb pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/beam.git


The following commit(s) were added to refs/heads/master by this push:
     new 80ae93217c5 Minor optimization for the common case of merging empty 
string sets. (#31803)
80ae93217c5 is described below

commit 80ae93217c5ac74e41cbedaeea7806fb0f05c2a9
Author: Robert Bradshaw <rober...@gmail.com>
AuthorDate: Mon Aug 5 09:49:55 2024 -0700

    Minor optimization for the common case of merging empty string sets. 
(#31803)
---
 .../apache/beam/runners/core/metrics/StringSetData.java | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git 
a/runners/core-java/src/main/java/org/apache/beam/runners/core/metrics/StringSetData.java
 
b/runners/core-java/src/main/java/org/apache/beam/runners/core/metrics/StringSetData.java
index 93dfb8e3ebc..466d4ad46eb 100644
--- 
a/runners/core-java/src/main/java/org/apache/beam/runners/core/metrics/StringSetData.java
+++ 
b/runners/core-java/src/main/java/org/apache/beam/runners/core/metrics/StringSetData.java
@@ -19,7 +19,6 @@ package org.apache.beam.runners.core.metrics;
 
 import com.google.auto.value.AutoValue;
 import java.io.Serializable;
-import java.util.HashSet;
 import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
@@ -50,12 +49,16 @@ public abstract class StringSetData implements Serializable 
{
    * Combines this {@link StringSetData} with other, both original 
StringSetData are left intact.
    */
   public StringSetData combine(StringSetData other) {
-    // do not merge other on this as this StringSetData might hold an 
immutable set like in case
-    // of  EmptyStringSetData
-    Set<String> combined = new HashSet<>();
-    combined.addAll(this.stringSet());
-    combined.addAll(other.stringSet());
-    return StringSetData.create(combined);
+    if (this.stringSet().isEmpty()) {
+      return other;
+    } else if (other.stringSet().isEmpty()) {
+      return this;
+    } else {
+      ImmutableSet.Builder<String> combined = ImmutableSet.builder();
+      combined.addAll(this.stringSet());
+      combined.addAll(other.stringSet());
+      return StringSetData.create(combined.build());
+    }
   }
 
   /**