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.metrics;
  
  import lombok.Getter;
  import lombok.Setter;
  import org.apache.skywalking.oap.server.core.analysis.metrics.annotation.ConstOne;
  import org.apache.skywalking.oap.server.core.analysis.metrics.annotation.Entrance;
  import org.apache.skywalking.oap.server.core.analysis.metrics.annotation.MetricsFunction;
  import org.apache.skywalking.oap.server.core.analysis.metrics.annotation.SourceFrom;
  import org.apache.skywalking.oap.server.core.query.sql.Function;
  import org.apache.skywalking.oap.server.core.storage.annotation.BanyanDB;
  import org.apache.skywalking.oap.server.core.storage.annotation.Column;
  
  @MetricsFunction(functionName = "longAvg")
  public abstract class LongAvgMetrics extends Metrics implements LongValueHolder {
  
      protected static final String SUMMATION = "summation";
      protected static final String COUNT = "count";
      protected static final String VALUE = "value";
  
      @Getter
      @Setter
      @Column(name = SUMMATION, storageOnly = true)
      @BanyanDB.MeasureField
      protected long summation;
      @Getter
      @Setter
      @Column(name = COUNT, storageOnly = true)
      @BanyanDB.MeasureField
      protected long count;
      @Getter
      @Setter
      @Column(name = VALUE, dataType = Column.ValueDataType.COMMON_VALUE, function = Function.Avg)
      @BanyanDB.MeasureField
      private long value;
  
      @Entrance
      public final void combine(@SourceFrom long summation, @ConstOne long count) {
          this.summation += summation;
          this.count += count;
      }
  
      @Override
      public final boolean combine(Metrics metrics) {
          LongAvgMetrics longAvgMetrics = (LongAvgMetrics) metrics;
          combine(longAvgMetrics.summation, longAvgMetrics.count);
          return true;
      }
  
      @Override
      public final void calculate() {
          this.value = this.summation / this.count;
      }
  }
  