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.worker;
  
  import java.util.Objects;
  import org.apache.skywalking.oap.server.core.analysis.metrics.Metrics;
  import org.apache.skywalking.oap.server.core.worker.AbstractWorker;
  import org.apache.skywalking.oap.server.library.module.ModuleDefineHolder;
  
  /**
   * MetricsTransWorker is transferring the metrics for down sampling. All streaming process metrics are in the minute
   * precision, but at the storage layer, in order to enhance the query performance, metrics could be saved in minute,
   * hour, day and month, including some of them through CoreModuleConfig#downsampling.
   */
  public class MetricsTransWorker extends AbstractWorker<Metrics> {
      private final MetricsPersistentWorker hourPersistenceWorker;
      private final MetricsPersistentWorker dayPersistenceWorker;
  
      public MetricsTransWorker(ModuleDefineHolder moduleDefineHolder,
                                MetricsPersistentWorker hourPersistenceWorker,
                                MetricsPersistentWorker dayPersistenceWorker) {
          super(moduleDefineHolder);
          this.hourPersistenceWorker = hourPersistenceWorker;
          this.dayPersistenceWorker = dayPersistenceWorker;
      }
  
      /**
       * Use the {@link Metrics#toHour()} and {@link Metrics#toDay()}to clone a new metrics instance then process the
       * downsampling. Then forward the data to different works of different precisions for another round
       * aggregation/merging.
       */
      @Override
      public void in(Metrics metrics) {
          if (Objects.nonNull(hourPersistenceWorker)) {
              hourPersistenceWorker.in(metrics.toHour());
          }
          if (Objects.nonNull(dayPersistenceWorker)) {
              dayPersistenceWorker.in(metrics.toDay());
          }
      }
  }
  