code: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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 org.apache.skywalking.oap.server.core.analysis;
  
  import java.util.Calendar;
  import org.apache.skywalking.oap.server.core.UnexpectedException;
  
  public class TimeBucket {
  
      /**
       * Record time bucket format in Second Unit.
       *
       * @param time Timestamp
       * @return time in second format
       */
      public static long getRecordTimeBucket(long time) {
          return getTimeBucket(time, DownSampling.Second);
      }
  
      /**
       * Record time bucket format in Minute Unit.
       *
       * @param time Timestamp
       * @return time in minute format
       */
      public static long getMinuteTimeBucket(long time) {
          return getTimeBucket(time, DownSampling.Minute);
      }
  
      /**
       * Convert TimeBucket to Timestamp in millisecond.
       *
       * @param timeBucket long
       * @return timestamp in millisecond unit
       */
      public static long getTimestamp(long timeBucket) {
          if (isSecondBucket(timeBucket)) {
              return getTimestamp(timeBucket, DownSampling.Second);
          } else if (isMinuteBucket(timeBucket)) {
              return getTimestamp(timeBucket, DownSampling.Minute);
          } else if (isHourBucket(timeBucket)) {
              return getTimestamp(timeBucket, DownSampling.Hour);
          } else if (isDayBucket(timeBucket)) {
              return getTimestamp(timeBucket, DownSampling.Day);
          } else {
              throw new UnexpectedException("Unknown downsampling value.");
          }
      }
  
      /**
       * The format of timeBucket in minute Unit is "yyyyMMddHHmmss", so which means the TimeBucket must be between
       * 10000000000000 and 99999999999999.
       */
      public static boolean isSecondBucket(long timeBucket) {
          return timeBucket < 99999999999999L && timeBucket > 10000000000000L;
      }
  
      /**
       * The format of timeBucket in minute Unit is "yyyyMMddHHmm", so which means the TimeBucket must be between
       * 100000000000 and 999999999999.
       */
      public static boolean isMinuteBucket(long timeBucket) {
          return timeBucket < 999999999999L && timeBucket > 100000000000L;
      }
  
      /**
       * The format of timeBucket in hour Unit is "yyyyMMddHH", so which means the TimeBucket must be between 1000000000
       * and 9999999999.
       */
      public static boolean isHourBucket(long timeBucket) {
          return timeBucket < 9999999999L && timeBucket > 1000000000L;
      }
  
      /**
       * The format of timeBucket in day Unit is "yyyyMMdd", so which means the TimeBucket must be between 10000000 and
       * 99999999.
       */
      public static boolean isDayBucket(long timeBucket) {
          return timeBucket < 99999999L && timeBucket > 10000000L;
      }
  
      /**
       * Convert TimeBucket to Timestamp in millisecond.
       *
       * @param timeBucket   long
       * @param downsampling Downsampling
       * @return timestamp in millisecond unit
       */
      public static long getTimestamp(long timeBucket, DownSampling downsampling) {
          Calendar calendar = Calendar.getInstance();
          calendar.setTimeInMillis(0);
          calendar.set(Calendar.MINUTE, 0);
          calendar.set(Calendar.HOUR_OF_DAY, 0);
  
          switch (downsampling) {
              case Second:
                  calendar.set(Calendar.SECOND, (int) (timeBucket % 100));
                  timeBucket /= 100;
                  // Fall through
              case Minute:
                  calendar.set(Calendar.MINUTE, (int) (timeBucket % 100));
                  timeBucket /= 100;
                  // Fall through
              case Hour:
                  calendar.set(Calendar.HOUR_OF_DAY, (int) (timeBucket % 100));
                  timeBucket /= 100;
                  // Fall through
              case Day:
                  calendar.set(Calendar.DAY_OF_MONTH, (int) (timeBucket % 100));
                  timeBucket /= 100;
                  calendar.set(Calendar.MONTH, (int) (timeBucket % 100) - 1);
                  calendar.set(Calendar.YEAR, (int) (timeBucket / 100));
                  break;
              default:
                  throw new UnexpectedException("Unknown downsampling value.");
          }
          return calendar.getTimeInMillis();
      }
  
      /**
       * Record timestamp bucket format in Downsampling Unit.
       *
       * @param timestamp    Timestamp
       * @param downsampling Downsampling
       * @return timestamp in downsampling format
       */
      public static long getTimeBucket(long timestamp, DownSampling downsampling) {
          Calendar calendar = Calendar.getInstance();
          calendar.setTimeInMillis(timestamp);
  
          long year = calendar.get(Calendar.YEAR);
          long month = calendar.get(Calendar.MONTH) + 1;
          long day = calendar.get(Calendar.DAY_OF_MONTH);
          long hour = calendar.get(Calendar.HOUR_OF_DAY);
          long minute = calendar.get(Calendar.MINUTE);
          long second = calendar.get(Calendar.SECOND);
  
          switch (downsampling) {
              case Second:
                  return year * 10000000000L + month * 100000000 + day * 1000000 + hour * 10000 + minute * 100 + second;
              case Minute:
                  return year * 100000000 + month * 1000000 + day * 10000 + hour * 100 + minute;
              case Hour:
                  return year * 1000000 + month * 10000 + day * 100 + hour;
              case Day:
                  return year * 10000 + month * 100 + day;
              default:
                  throw new UnexpectedException("Unknown downsampling value.");
          }
      }
  }
  