HBASE-25740 - Backport HBASE-25629 to branch-1 (#3130)

Signed-off-by Reid Chan <reidchan@apache.org>

Author: gjacoby126

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/compactions/CurrentHourProvider.java

@@ -24,7 +24,10 @@
 
 @InterfaceAudience.Private
 public class CurrentHourProvider {
-  private CurrentHourProvider() { throw new AssertionError(); }
+
+  private CurrentHourProvider() {
+    throw new AssertionError();
+  }
 
   private static final class Tick {
     final int currentHour;
@@ -36,7 +39,7 @@ private static final class Tick {
     }
   }
 
-  static Tick nextTick() {
+  private static Tick nextTick() {
     Calendar calendar = new GregorianCalendar();
     calendar.setTimeInMillis(EnvironmentEdgeManager.currentTime());
     int currentHour = calendar.get(Calendar.HOUR_OF_DAY);
@@ -51,15 +54,20 @@ private static void moveToNextHour(Calendar calendar) {
     calendar.set(Calendar.MILLISECOND, 0);
   }
 
-  static volatile Tick tick = nextTick();
+  private static volatile Tick tick = nextTick();
 
   public static int getCurrentHour() {
     Tick tick = CurrentHourProvider.tick;
     if (EnvironmentEdgeManager.currentTime() < tick.expirationTimeInMillis) {
       return tick.currentHour;
     }
-
-    CurrentHourProvider.tick = tick = nextTick();
+    tick = nextTick();
+    CurrentHourProvider.tick = tick;
     return tick.currentHour;
   }
+
+  //RestrictedApi - only to be called for tests
+  static void advanceTick() {
+    tick = nextTick();
+  }
 }

hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/compactions/TestCurrentHourProvider.java

@@ -19,7 +19,9 @@
 
 import static org.junit.Assert.assertEquals;
 
+import com.google.common.collect.Lists;
 import java.util.Date;
+import java.util.List;
 import java.util.TimeZone;
 import org.apache.hadoop.hbase.testclassification.RegionServerTests;
 import org.apache.hadoop.hbase.testclassification.SmallTests;
@@ -31,20 +33,20 @@
 @Category({RegionServerTests.class, SmallTests.class})
 public class TestCurrentHourProvider {
 
+  private static final List<String> ZONE_IDS = Lists.newArrayList("UTC", "US/Pacific", "Etc/GMT+8");
+
   /**
-   * In timezone GMT+08:00, the unix time of 2020-08-20 11:52:41 is 1597895561000
-   * and the unix time of 2020-08-20 15:04:00 is 1597907081000,
-   * by calculating the delta time to get expected time in current timezone,
-   * then we can get special hour no matter which timezone it runs.
-   *
-   * In addition, we should consider the Daylight Saving Time.
-   * 1. If in DaylightTime, we need reduce one hour.
-   * 2. If in DaylightTime and timezone is "Antarctica/Troll", we need reduce two hours.
+   * In timezone GMT+08:00, the unix time of 2020-08-20 11:52:41 is 1597895561000 and the unix time
+   * of 2020-08-20 15:04:00 is 1597907081000, by calculating the delta time to get expected time in
+   * current timezone, then we can get special hour no matter which timezone it runs.
+   * <p/>
+   * In addition, we should consider the Daylight Saving Time. If in DaylightTime, we need reduce
+   * one hour.
    */
   @Test
   public void testWithEnvironmentEdge() {
     // test for all available zoneID
-    for (String zoneID : TimeZone.getAvailableIDs()) {
+    for (String zoneID : ZONE_IDS) {
       TimeZone timezone = TimeZone.getTimeZone(zoneID);
       TimeZone.setDefault(timezone);
 
@@ -57,12 +59,10 @@ public long currentTime() {
           return timeFor11;
         }
       });
-      CurrentHourProvider.tick = CurrentHourProvider.nextTick();
+      CurrentHourProvider.advanceTick();
       int hour11 = CurrentHourProvider.getCurrentHour();
       if (TimeZone.getDefault().inDaylightTime(new Date(timeFor11))) {
-        hour11 = "Antarctica/Troll".equals(zoneID) ?
-          CurrentHourProvider.getCurrentHour() - 2 :
-          CurrentHourProvider.getCurrentHour() - 1;
+        hour11 = CurrentHourProvider.getCurrentHour() - 1;
       }
       assertEquals(11, hour11);
 
@@ -75,12 +75,10 @@ public long currentTime() {
           return timeFor15;
         }
       });
-      CurrentHourProvider.tick = CurrentHourProvider.nextTick();
+      CurrentHourProvider.advanceTick();
       int hour15 = CurrentHourProvider.getCurrentHour();
       if (TimeZone.getDefault().inDaylightTime(new Date(timeFor15))) {
-        hour15 = "Antarctica/Troll".equals(zoneID) ?
-          CurrentHourProvider.getCurrentHour() - 2 :
-          CurrentHourProvider.getCurrentHour() - 1;
+        hour15 = CurrentHourProvider.getCurrentHour() - 1;
       }
       assertEquals(15, hour15);
     }