Add test and benchmarks for SimpleDateFormat.

Add a test that verifies that SimpleDateFormat uses zoneStrings for
parsing, when they are provided by the user. This test simply checks
existing behaviour in preparation of upcoming changes.

The SimpleDateFormatBenchmark has a main() method in addition to the
usual caliper tests to allow measuring some first-call times. Otherwise
the impact of calling a method on cold caches would be lost in the
caliper tests.

Test: vogar libcore/luni/src/test/java/libcore/java/text/SimpleDateFormatTest.java
Bug: 20879084
Change-Id: I01581a31566df8fa1b60ccce0c8ddecb0230b39e

2 files changed, 129 insertions, 0 deletions

diff --git a/benchmarks/src/benchmarks/regression/SimpleDateFormatBenchmark.java b/benchmarks/src/benchmarks/regression/SimpleDateFormatBenchmark.java
new file mode 100644
index 0000000000..b9becc7687
--- /dev/null
+++ b/benchmarks/src/benchmarks/regression/SimpleDateFormatBenchmark.java
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package benchmarks.regression;
+
+import android.icu.text.TimeZoneNames;
+
+import java.text.DateFormatSymbols;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Arrays;
+import java.util.Date;
+import java.util.Locale;
+import java.util.TimeZone;
+
+/**
+ * Benchmark for java.text.SimpleDateFormat. This tests common formatting, parsing and creation
+ * operations with a specific focus on TimeZone handling.
+ */
+public class SimpleDateFormatBenchmark {
+    public void time_createFormatWithTimeZone(int reps) {
+        for (int i = 0; i < reps; i++) {
+            SimpleDateFormat sdf = new SimpleDateFormat("yyyy.MM.dd z");
+        }
+    }
+
+    public void time_parseWithTimeZoneShort(int reps) throws ParseException {
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy.MM.dd z");
+        for (int i = 0; i < reps; i++) {
+            sdf.parse("2000.01.01 PST");
+        }
+    }
+
+    public void time_parseWithTimeZoneLong(int reps) throws ParseException {
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy.MM.dd zzzz");
+        for (int i = 0; i < reps; i++) {
+            sdf.parse("2000.01.01 Pacific Standard Time");
+        }
+    }
+
+    public void time_parseWithoutTimeZone(int reps) throws ParseException {
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy.MM.dd");
+        for (int i = 0; i < reps; i++) {
+            sdf.parse("2000.01.01");
+        }
+    }
+
+    public void time_createAndParseWithTimeZoneShort(int reps) throws ParseException {
+        for (int i = 0; i < reps; i++) {
+            SimpleDateFormat sdf = new SimpleDateFormat("yyyy.MM.dd z");
+            sdf.parse("2000.01.01 PST");
+        }
+    }
+
+    public void time_createAndParseWithTimeZoneLong(int reps) throws ParseException {
+        for (int i = 0; i < reps; i++) {
+            SimpleDateFormat sdf = new SimpleDateFormat("yyyy.MM.dd zzzz");
+            sdf.parse("2000.01.01 Pacific Standard Time");
+        }
+    }
+
+    public void time_formatWithTimeZoneShort(int reps) {
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy.MM.dd z");
+        for (int i = 0; i < reps; i++) {
+            sdf.format(new Date());
+        }
+    }
+
+    public void time_formatWithTimeZoneLong(int reps) {
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy.MM.dd zzzz");
+        for (int i = 0; i < reps; i++) {
+            sdf.format(new Date());
+        }
+    }
+
+    /**
+     * Times first-time execution to measure effects of initial loading of data that's lost in
+     * full caliper benchmarks.
+     */
+    public static void main(String[] args) throws ParseException {
+        long start, end;
+
+        Locale locale = Locale.GERMAN;
+        start = System.nanoTime();
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy.MM.dd zzzz", locale);
+        end = System.nanoTime();
+        System.out.printf("Creating first SDF: %,d ns\n", end-start);
+
+        // N code had special cases for currently-set and for default timezone. We want to measure
+        // the generic case.
+        sdf.setTimeZone(TimeZone.getTimeZone("Hongkong"));
+
+        start = System.nanoTime();
+        sdf.parse("2000.1.1 Kubanische Normalzeit");
+        end = System.nanoTime();
+        System.out.printf("First parse: %,d ns\n", end-start);
+
+        start = System.nanoTime();
+        sdf.format(new Date());
+        end = System.nanoTime();
+        System.out.printf("First format: %,d ns\n", end-start);
+    }
+}
diff --git a/luni/src/test/java/libcore/java/text/SimpleDateFormatTest.java b/luni/src/test/java/libcore/java/text/SimpleDateFormatTest.java
index a00110489f..d9656a0e2d 100644
--- a/luni/src/test/java/libcore/java/text/SimpleDateFormatTest.java
+++ b/luni/src/test/java/libcore/java/text/SimpleDateFormatTest.java
@@ -453,6 +453,20 @@ public class SimpleDateFormatTest extends junit.framework.TestCase {
         assertEquals(tz, df.getTimeZone());
     }
 
+    public void testZoneStringsUsedForParsingWhenPresent() throws ParseException {
+        DateFormatSymbols symbols = DateFormatSymbols.getInstance(Locale.ENGLISH);
+        String[][] zoneStrings = symbols.getZoneStrings();
+        TimeZone tz = TimeZone.getTimeZone(zoneStrings[0][0]);
+        zoneStrings[0][1] = "CustomTimeZone";
+        symbols.setZoneStrings(zoneStrings);
+
+        SimpleDateFormat sdf = new SimpleDateFormat("dd MM yyyy HH:mm zzz", symbols);
+
+        Date gmtDate = sdf.parse("1 1 2000 12:00 GMT");
+        Date customDate = sdf.parse("1 1 2000 12:00 CustomTimeZone");
+        assertEquals(tz.getOffset(gmtDate.getTime()), customDate.getTime() - gmtDate.getTime());
+    }
+
     public void testTimeZoneFormattingRespectsSetZoneStrings() throws ParseException {
         DateFormatSymbols symbols = DateFormatSymbols.getInstance(Locale.ENGLISH);
         String[][] zoneStrings = symbols.getZoneStrings();