/**
 * 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.hadoop.hbase.regionserver;

import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.ScheduledChore;
import org.apache.hadoop.hbase.Server;
import org.apache.hadoop.hbase.Stoppable;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.executor.EventType;
import org.apache.hadoop.hbase.regionserver.Region;
import org.apache.hadoop.hbase.regionserver.RegionServerServices;
import org.apache.hadoop.hbase.regionserver.Store;

import com.google.common.annotations.VisibleForTesting;

/**
 * A chore service that periodically cleans up the compacted files when there are no active readers
 * using those compacted files and also helps in clearing the block cache with these compacted
 * file entries
 */
@InterfaceAudience.Private
public class CompactedHFilesDischarger extends ScheduledChore {
  private static final Log LOG = LogFactory.getLog(CompactedHFilesDischarger.class);
  private RegionServerServices regionServerServices;
  // Default is to use executor
  @VisibleForTesting
  private boolean useExecutor = true;

  /**
   * @param period the period of time to sleep between each run
   * @param stopper the stopper
   * @param regionServerServices the region server that starts this chore
   */
  public CompactedHFilesDischarger(final int period, final Stoppable stopper,
      final RegionServerServices regionServerServices) {
    // Need to add the config classes
    super("CompactedHFilesCleaner", stopper, period);
    this.regionServerServices = regionServerServices;
  }

  /**
   * @param period the period of time to sleep between each run
   * @param stopper the stopper
   * @param regionServerServices the region server that starts this chore
   * @param useExecutor true if to use the region server's executor service, false otherwise
   */
  @VisibleForTesting
  public CompactedHFilesDischarger(final int period, final Stoppable stopper,
      final RegionServerServices regionServerServices, boolean useExecutor) {
    // Need to add the config classes
    this(period, stopper, regionServerServices);
    this.useExecutor = useExecutor;
  }

  @Override
  public void chore() {
    // Noop if rss is null. This will never happen in a normal condition except for cases
    // when the test case is not spinning up a cluster
    if (regionServerServices == null) return;
    List<Region> onlineRegions = regionServerServices.getOnlineRegions();
    if (onlineRegions != null) {
      for (Region region : onlineRegions) {
        if (LOG.isTraceEnabled()) {
          LOG.trace(
              "Started the compacted hfiles cleaner for the region " + region.getRegionInfo());
        }
        for (Store store : region.getStores()) {
          try {
            if (useExecutor && regionServerServices != null) {
              CompactedHFilesDischargeHandler handler = new CompactedHFilesDischargeHandler(
                  (Server) regionServerServices, EventType.RS_COMPACTED_FILES_DISCHARGER,
                  (HStore) store);
              regionServerServices.getExecutorService().submit(handler);
            } else {
              // call synchronously if the RegionServerServices are not
              // available
              store.closeAndArchiveCompactedFiles();
            }
            if (LOG.isTraceEnabled()) {
              LOG.trace("Completed archiving the compacted files for the region "
                  + region.getRegionInfo() + " under the store " + store.getColumnFamilyName());
            }
          } catch (Exception e) {
            LOG.error("Exception while trying to close and archive the compacted store "
                + "files of the store  " + store.getColumnFamilyName() + " in the" + " region "
                + region.getRegionInfo(), e);
          }
        }
        if (LOG.isTraceEnabled()) {
          LOG.trace(
              "Completed the compacted hfiles cleaner for the region " + region.getRegionInfo());
        }
      }
    }
  }
}