001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018package org.apache.hadoop.hbase.regionserver.compactions; 019 020import java.util.Calendar; 021import java.util.GregorianCalendar; 022 023import org.apache.hadoop.hbase.util.EnvironmentEdgeManager; 024import org.apache.yetus.audience.InterfaceAudience; 025 026@InterfaceAudience.Private 027public class CurrentHourProvider { 028 private CurrentHourProvider() { throw new AssertionError(); } 029 030 private static final class Tick { 031 final int currentHour; 032 final long expirationTimeInMillis; 033 034 Tick(int currentHour, long expirationTimeInMillis) { 035 this.currentHour = currentHour; 036 this.expirationTimeInMillis = expirationTimeInMillis; 037 } 038 } 039 040 static Tick nextTick() { 041 Calendar calendar = new GregorianCalendar(); 042 calendar.setTimeInMillis(EnvironmentEdgeManager.currentTime()); 043 int currentHour = calendar.get(Calendar.HOUR_OF_DAY); 044 moveToNextHour(calendar); 045 return new Tick(currentHour, calendar.getTimeInMillis()); 046 } 047 048 private static void moveToNextHour(Calendar calendar) { 049 calendar.add(Calendar.HOUR_OF_DAY, 1); 050 calendar.set(Calendar.MINUTE, 0); 051 calendar.set(Calendar.SECOND, 0); 052 calendar.set(Calendar.MILLISECOND, 0); 053 } 054 055 static volatile Tick tick = nextTick(); 056 057 public static int getCurrentHour() { 058 Tick tick = CurrentHourProvider.tick; 059 if (EnvironmentEdgeManager.currentTime() < tick.expirationTimeInMillis) { 060 return tick.currentHour; 061 } 062 063 CurrentHourProvider.tick = tick = nextTick(); 064 return tick.currentHour; 065 } 066}