From 00db6563406a6225fc06ceab88309336afde30b7 Mon Sep 17 00:00:00 2001
From: Matt Jarvie <mjarvie@newrelic.com>
Date: Mon, 5 Aug 2019 11:39:02 -0700
Subject: [PATCH] KAFKA-8736: Streams performance improvement, use isEmpty()
 rather than size() == 0

---
 .../org/apache/kafka/streams/state/internals/NamedCache.java  | 4 ++++
 .../org/apache/kafka/streams/state/internals/ThreadCache.java | 4 ++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/streams/src/main/java/org/apache/kafka/streams/state/internals/NamedCache.java b/streams/src/main/java/org/apache/kafka/streams/state/internals/NamedCache.java
index 0201f20f9fbf4..ec53dfa5d46cd 100644
--- a/streams/src/main/java/org/apache/kafka/streams/state/internals/NamedCache.java
+++ b/streams/src/main/java/org/apache/kafka/streams/state/internals/NamedCache.java
@@ -266,6 +266,10 @@ public long size() {
         return cache.size();
     }
 
+    public boolean isEmpty() {
+        return cache.isEmpty();
+    }
+
     synchronized Iterator<Map.Entry<Bytes, LRUNode>> subMapIterator(final Bytes from, final Bytes to) {
         return cache.subMap(from, true, to, true).entrySet().iterator();
     }
diff --git a/streams/src/main/java/org/apache/kafka/streams/state/internals/ThreadCache.java b/streams/src/main/java/org/apache/kafka/streams/state/internals/ThreadCache.java
index 0db6c78a5772e..116b1ef8b7d1a 100644
--- a/streams/src/main/java/org/apache/kafka/streams/state/internals/ThreadCache.java
+++ b/streams/src/main/java/org/apache/kafka/streams/state/internals/ThreadCache.java
@@ -193,7 +193,7 @@ public MemoryLRUCacheBytesIterator all(final String namespace) {
         }
         return new MemoryLRUCacheBytesIterator(cache.allIterator());
     }
-    
+
     public long size() {
         long size = 0;
         for (final NamedCache cache : caches.values()) {
@@ -235,7 +235,7 @@ private void maybeEvict(final String namespace) {
             // a put on another cache. So even though the sizeInBytes() is
             // still > maxCacheSizeBytes there is nothing to evict from this
             // namespaced cache.
-            if (cache.size() == 0) {
+            if (cache.isEmpty()) {
                 return;
             }
             cache.evict();