CountAccumulator.java

/*
 * Copyright (c) 2001-2017, Zoltan Farkas All Rights Reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * Additionally licensed with:
 *
 * Licensed 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.spf4j.perf.impl.acc;

import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import javax.annotation.Nullable;
import org.spf4j.perf.MeasurementAccumulator;
import org.spf4j.perf.MeasurementsInfo;
import org.spf4j.perf.impl.MeasurementsInfoImpl;
import org.spf4j.tsdb2.avro.Aggregation;
import org.spf4j.tsdb2.avro.MeasurementType;

/**
 * @author zoly
 */
public final class CountAccumulator
        extends AbstractMeasurementAccumulator {

  private static final String[] MEASUREMENTS = {"count"};

  private static final Aggregation[] AGGS = {Aggregation.SUM};

  private long counter;
  private final MeasurementsInfo info;

  private CountAccumulator(final Object measuredEntity, final String description,
          final String unitOfMeasurement, final long counter) {
    this.info = new MeasurementsInfoImpl(measuredEntity, description,
            MEASUREMENTS, new String[]{unitOfMeasurement}, AGGS, MeasurementType.COUNTER);
    this.counter = counter;
  }

  public CountAccumulator(final Object measuredEntity, final String description,
          final String unitOfMeasurement) {
    this(measuredEntity, description, unitOfMeasurement, 0);
  }

  public String getUnitOfMeasurement() {
    return info.getMeasurementUnit(0);
  }

  @Override
  public synchronized void increment() {
    counter++;
  }

  @Override
  public synchronized void record(final long measurement) {
    counter += measurement;
  }

  @Override
  @SuppressFBWarnings("PZLA_PREFER_ZERO_LENGTH_ARRAYS")
  @Nullable
  public synchronized long[] get() {
    if (counter == 0) {
      return null;
    } else {
      return new long[]{counter};
    }
  }

  @SuppressFBWarnings({"CLI_CONSTANT_LIST_INDEX", "NOS_NON_OWNED_SYNCHRONIZATION"})
  @Override
  public MeasurementAccumulator aggregate(final MeasurementAccumulator mSource) {
    if (mSource instanceof CountAccumulator) {
      CountAccumulator other = (CountAccumulator) mSource;
      long[] measurements = other.get();
      if (measurements != null) {
        synchronized (this) {
          return new CountAccumulator(this.info.getMeasuredEntity(), this.info.getDescription(),
                  getUnitOfMeasurement(), counter + measurements[0]);
        }
      } else {
        return this.createClone();
      }
    } else {
      throw new IllegalArgumentException("Cannot aggregate " + this + " with " + mSource);
    }
  }

  @Override
  public synchronized CountAccumulator createClone() {
    return new CountAccumulator(this.info.getMeasuredEntity(),
            this.info.getDescription(), getUnitOfMeasurement(), counter);
  }

  @Override
  public CountAccumulator createLike(final Object entity) {
    return new CountAccumulator(entity, this.info.getDescription(), getUnitOfMeasurement());
  }

  @Override
  public MeasurementsInfo getInfo() {
    return info;
  }

  @Override
  @Nullable
  public synchronized MeasurementAccumulator reset() {
    if (counter == 0) {
      return null;
    } else {
      MeasurementAccumulator result = this.createClone();
      counter = 0;
      return result;
    }
  }

  @Override
  @SuppressFBWarnings("PZLA_PREFER_ZERO_LENGTH_ARRAYS")
  @Nullable
  public long[] getThenReset() {
    final MeasurementAccumulator vals = reset();
    if (vals == null) {
      return null;
    } else {
      return vals.get();
    }
  }

  @Override
  public String toString() {
    return "CountingAccumulator{" + "counter=" + counter + ", info=" + info + '}';
  }

}