From 438c969b7b07eeef0158b089e5a168849e04bf56 Mon Sep 17 00:00:00 2001
From: Sergey Tsypanov <stsypanov@openjdk.org>
Date: Wed, 29 Mar 2023 18:32:14 +0000
Subject: [PATCH] 8304976: Optimize
 DateTimeFormatterBuilder.ZoneTextPrinterParser.getTree()

Reviewed-by: naoto
---
 .../time/format/DateTimeFormatterBuilder.java | 11 ++--
 .../ZonedDateTimeFormatterBenchmark.java      | 55 +++++++++++++++++++
 2 files changed, 61 insertions(+), 5 deletions(-)
 create mode 100644 test/micro/org/openjdk/bench/java/time/format/ZonedDateTimeFormatterBenchmark.java

diff --git a/src/java.base/share/classes/java/time/format/DateTimeFormatterBuilder.java b/src/java.base/share/classes/java/time/format/DateTimeFormatterBuilder.java
index d4ee80d787d..c69b08e4a5f 100644
--- a/src/java.base/share/classes/java/time/format/DateTimeFormatterBuilder.java
+++ b/src/java.base/share/classes/java/time/format/DateTimeFormatterBuilder.java
@@ -4516,9 +4516,9 @@ public final class DateTimeFormatterBuilder {
 
         // cache per instance for now
         private final Map<Locale, Entry<Integer, SoftReference<PrefixTree>>>
-            cachedTree = new HashMap<>();
+            cachedTree = HashMap.newHashMap(1);
         private final Map<Locale, Entry<Integer, SoftReference<PrefixTree>>>
-            cachedTreeCI = new HashMap<>();
+            cachedTreeCI = HashMap.newHashMap(1);
 
         @Override
         protected PrefixTree getTree(DateTimeParseContext context) {
@@ -4527,9 +4527,8 @@ public final class DateTimeFormatterBuilder {
             }
             Locale locale = context.getLocale();
             boolean isCaseSensitive = context.isCaseSensitive();
-            Set<String> regionIds = new HashSet<>(ZoneRulesProvider.getAvailableZoneIds());
-            Set<String> nonRegionIds = new HashSet<>(64);
-            int regionIdsSize = regionIds.size();
+            Set<String> availableZoneIds = ZoneRulesProvider.getAvailableZoneIds();
+            int regionIdsSize = availableZoneIds.size();
 
             Map<Locale, Entry<Integer, SoftReference<PrefixTree>>> cached =
                 isCaseSensitive ? cachedTree : cachedTreeCI;
@@ -4542,6 +4541,8 @@ public final class DateTimeFormatterBuilder {
                 (tree = entry.getValue().get()) == null)) {
                 tree = PrefixTree.newTree(context);
                 zoneStrings = TimeZoneNameUtility.getZoneStrings(locale);
+                Set<String> nonRegionIds = HashSet.newHashSet(64);
+                Set<String> regionIds = new HashSet<>(availableZoneIds);
                 for (String[] names : zoneStrings) {
                     String zid = names[0];
                     if (!regionIds.remove(zid)) {
diff --git a/test/micro/org/openjdk/bench/java/time/format/ZonedDateTimeFormatterBenchmark.java b/test/micro/org/openjdk/bench/java/time/format/ZonedDateTimeFormatterBenchmark.java
new file mode 100644
index 00000000000..00a3729a337
--- /dev/null
+++ b/test/micro/org/openjdk/bench/java/time/format/ZonedDateTimeFormatterBenchmark.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package org.openjdk.bench.java.time.format;
+
+import org.openjdk.jmh.annotations.*;
+
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeFormatterBuilder;
+import java.util.concurrent.TimeUnit;
+
+@Fork(4)
+@State(Scope.Thread)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@Warmup(iterations = 5, time = 1)
+@Measurement(iterations = 5, time = 1)
+public class ZonedDateTimeFormatterBenchmark {
+
+    private static final DateTimeFormatter df = new DateTimeFormatterBuilder()
+            .appendPattern("yyyy:MM:dd:HH:mm:v")
+            .toFormatter();
+    private static final String TEXT = "2015:03:10:12:13:ECT";
+
+    @Setup
+    public void setUp() {
+        ZonedDateTime.parse(TEXT, df);
+    }
+
+    @Benchmark
+    public ZonedDateTime parse() {
+        return ZonedDateTime.parse(TEXT, df);
+    }
+
+}