/**
    * 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.Collection;
  import java.util.List;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.TimeUnit;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.CompatibilitySingletonFactory;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.HDFSBlocksDistribution;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.ServerName;
  import org.apache.hadoop.hbase.io.hfile.BlockCache;
  import org.apache.hadoop.hbase.io.hfile.CacheConfig;
  import org.apache.hadoop.hbase.io.hfile.CacheStats;
  import org.apache.hadoop.hbase.wal.WALProvider;
  import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
  import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
  import org.apache.hadoop.metrics2.MetricsExecutor;
  
  /**
   * Impl for exposing HRegionServer Information through Hadoop's metrics 2 system.
   */
  @InterfaceAudience.Private
  class MetricsRegionServerWrapperImpl
      implements MetricsRegionServerWrapper {
  
    private static final Log LOG = LogFactory.getLog(MetricsRegionServerWrapperImpl.class);
  
    private final HRegionServer regionServer;
  
    private BlockCache blockCache;
  
    private volatile long numStores = 0;
    private volatile long numWALFiles = 0;
    private volatile long walFileSize = 0;
    private volatile long numStoreFiles = 0;
    private volatile long memstoreSize = 0;
    private volatile long storeFileSize = 0;
    private volatile long maxStoreFileAge = 0;
    private volatile long minStoreFileAge = 0;
    private volatile long avgStoreFileAge = 0;
    private volatile long numReferenceFiles = 0;
    private volatile double requestsPerSecond = 0.0;
    private volatile long readRequestsCount = 0;
    private volatile long writeRequestsCount = 0;
    private volatile double readRequestsRate = 0;
    private volatile double writeRequestsRate = 0;
    private volatile long checkAndMutateChecksFailed = 0;
    private volatile long checkAndMutateChecksPassed = 0;
    private volatile long storefileIndexSize = 0;
    private volatile long totalStaticIndexSize = 0;
    private volatile long totalStaticBloomSize = 0;
    private volatile long numMutationsWithoutWAL = 0;
    private volatile long dataInMemoryWithoutWAL = 0;
    private volatile double percentFileLocal = 0;
    private volatile double percentFileLocalSecondaryRegions = 0;
    private volatile long flushedCellsCount = 0;
    private volatile long compactedCellsCount = 0;
    private volatile long majorCompactedCellsCount = 0;
    private volatile long flushedCellsSize = 0;
    private volatile long compactedCellsSize = 0;
    private volatile long majorCompactedCellsSize = 0;
    private volatile long blockedRequestsCount = 0L;
    private volatile long averageRegionSize = 0L;
  
    private CacheStats cacheStats;
    private ScheduledExecutorService executor;
    private Runnable runnable;
    private long period;
  
    public MetricsRegionServerWrapperImpl(final HRegionServer regionServer) {
      this.regionServer = regionServer;
      initBlockCache();
  
      this.period =
          regionServer.conf.getLong(HConstants.REGIONSERVER_METRICS_PERIOD,
            HConstants.DEFAULT_REGIONSERVER_METRICS_PERIOD);
 
     this.executor = CompatibilitySingletonFactory.getInstance(MetricsExecutor.class).getExecutor();
     this.runnable = new RegionServerMetricsWrapperRunnable();
     this.executor.scheduleWithFixedDelay(this.runnable, this.period, this.period,
       TimeUnit.MILLISECONDS);
 
     if (LOG.isInfoEnabled()) {
       LOG.info("Computing regionserver metrics every " + this.period + " milliseconds");
     }
   }
 
   /**
    * It's possible that due to threading the block cache could not be initialized
    * yet (testing multiple region servers in one jvm).  So we need to try and initialize
    * the blockCache and cacheStats reference multiple times until we succeed.
    */
   private synchronized  void initBlockCache() {
     CacheConfig cacheConfig = this.regionServer.cacheConfig;
     if (cacheConfig != null && this.blockCache == null) {
       this.blockCache = cacheConfig.getBlockCache();
     }
 
     if (this.blockCache != null && this.cacheStats == null) {
       this.cacheStats = blockCache.getStats();
     }
   }
 
   @Override
   public String getClusterId() {
     return regionServer.getClusterId();
   }
 
   @Override
   public long getStartCode() {
     return regionServer.getStartcode();
   }
 
   @Override
   public String getZookeeperQuorum() {
     ZooKeeperWatcher zk = regionServer.getZooKeeper();
     if (zk == null) {
       return "";
     }
     return zk.getQuorum();
   }
 
   @Override
   public String getCoprocessors() {
     String[] coprocessors = regionServer.getRegionServerCoprocessors();
     if (coprocessors == null || coprocessors.length == 0) {
       return "";
     }
     return StringUtils.join(coprocessors, ", ");
   }
 
   @Override
   public String getServerName() {
     ServerName serverName = regionServer.getServerName();
     if (serverName == null) {
       return "";
     }
     return serverName.getServerName();
   }
 
   @Override
   public long getNumOnlineRegions() {
     Collection<Region> onlineRegionsLocalContext = regionServer.getOnlineRegionsLocalContext();
     if (onlineRegionsLocalContext == null) {
       return 0;
     }
     return onlineRegionsLocalContext.size();
   }
 
   @Override
   public long getTotalRequestCount() {
     return regionServer.rpcServices.requestCount.get();
   }
 
   @Override
   public int getSplitQueueSize() {
     if (this.regionServer.compactSplitThread == null) {
       return 0;
     }
     return this.regionServer.compactSplitThread.getSplitQueueSize();
   }
 
   @Override
   public int getCompactionQueueSize() {
     //The thread could be zero.  if so assume there is no queue.
     if (this.regionServer.compactSplitThread == null) {
       return 0;
     }
     return this.regionServer.compactSplitThread.getCompactionQueueSize();
   }
 
   @Override
   public int getSmallCompactionQueueSize() {
     //The thread could be zero.  if so assume there is no queue.
     if (this.regionServer.compactSplitThread == null) {
       return 0;
     }
     return this.regionServer.compactSplitThread.getSmallCompactionQueueSize();
   }
 
   @Override
   public int getLargeCompactionQueueSize() {
     //The thread could be zero.  if so assume there is no queue.
     if (this.regionServer.compactSplitThread == null) {
       return 0;
     }
     return this.regionServer.compactSplitThread.getLargeCompactionQueueSize();
   }
 
   @Override
   public int getFlushQueueSize() {
     //If there is no flusher there should be no queue.
     if (this.regionServer.cacheFlusher == null) {
       return 0;
     }
     return this.regionServer.cacheFlusher.getFlushQueueSize();
   }
 
   @Override
   public long getBlockCacheCount() {
     if (this.blockCache == null) {
       return 0;
     }
     return this.blockCache.getBlockCount();
   }
 
   @Override
   public long getBlockCacheSize() {
     if (this.blockCache == null) {
       return 0;
     }
     return this.blockCache.getCurrentSize();
   }
 
   @Override
   public long getBlockCacheFreeSize() {
     if (this.blockCache == null) {
       return 0;
     }
     return this.blockCache.getFreeSize();
   }
 
   @Override
   public long getBlockCacheHitCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return this.cacheStats.getHitCount();
   }
 
   @Override
   public long getBlockCachePrimaryHitCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return this.cacheStats.getPrimaryHitCount();
   }
 
   @Override
   public long getBlockCacheMissCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return this.cacheStats.getMissCount();
   }
 
   @Override
   public long getBlockCachePrimaryMissCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return this.cacheStats.getPrimaryMissCount();
   }
 
   @Override
   public long getBlockCacheEvictedCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return this.cacheStats.getEvictedCount();
   }
 
   @Override
   public long getBlockCachePrimaryEvictedCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return this.cacheStats.getPrimaryEvictedCount();
   }
 
   @Override
   public double getBlockCacheHitPercent() {
     if (this.cacheStats == null) {
       return 0;
     }
     double ratio = this.cacheStats.getHitRatio();
     if (Double.isNaN(ratio)) {
       ratio = 0;
     }
     return (ratio * 100);
   }
 
   @Override
   public double getBlockCacheHitCachingPercent() {
     if (this.cacheStats == null) {
       return 0;
     }
 
     double ratio = this.cacheStats.getHitCachingRatio();
 
     if (Double.isNaN(ratio)) {
       ratio = 0;
     }
     return (ratio * 100);
   }
 
   @Override
   public long getBlockCacheFailedInsertions() {
     if (this.cacheStats == null) {
       return 0;
     }
     return this.cacheStats.getFailedInserts();
   }
 
   @Override public void forceRecompute() {
     this.runnable.run();
   }
 
   @Override
   public long getNumStores() {
     return numStores;
   }
   
   @Override
   public long getNumWALFiles() {
     return numWALFiles;
   }
 
   @Override
   public long getWALFileSize() {
     return walFileSize;
   }
   
   @Override
   public long getNumStoreFiles() {
     return numStoreFiles;
   }
 
   @Override
   public long getMaxStoreFileAge() {
     return maxStoreFileAge;
   }
 
   @Override
   public long getMinStoreFileAge() {
     return minStoreFileAge;
   }
 
   @Override
   public long getAvgStoreFileAge() {
     return avgStoreFileAge;
   }
 
   @Override
   public long getNumReferenceFiles() {
     return numReferenceFiles;
   }
 
   @Override
   public long getMemstoreSize() {
     return memstoreSize;
   }
 
   @Override
   public long getStoreFileSize() {
     return storeFileSize;
   }
 
   @Override public double getRequestsPerSecond() {
     return requestsPerSecond;
   }
 
   @Override
   public long getReadRequestsCount() {
     return readRequestsCount;
   }
 
   @Override
   public long getWriteRequestsCount() {
     return writeRequestsCount;
   }
 
   @Override
   public double getReadRequestsRate() {
     return readRequestsRate;
   }
 
   @Override
   public double getWriteRequestsRate() {
     return writeRequestsRate;
   }
 
   @Override
   public long getRpcGetRequestsCount() {
     return regionServer.rpcServices.rpcGetRequestCount.get();
   }
 
   @Override
   public long getRpcScanRequestsCount() {
     return regionServer.rpcServices.rpcScanRequestCount.get();
   }
 
   @Override
   public long getRpcMultiRequestsCount() {
     return regionServer.rpcServices.rpcMultiRequestCount.get();
   }
 
   @Override
   public long getRpcMutateRequestsCount() {
     return regionServer.rpcServices.rpcMutateRequestCount.get();
   }
 
   @Override
   public long getCheckAndMutateChecksFailed() {
     return checkAndMutateChecksFailed;
   }
 
   @Override
   public long getCheckAndMutateChecksPassed() {
     return checkAndMutateChecksPassed;
   }
 
   @Override
   public long getStoreFileIndexSize() {
     return storefileIndexSize;
   }
 
   @Override
   public long getTotalStaticIndexSize() {
     return totalStaticIndexSize;
   }
 
   @Override
   public long getTotalStaticBloomSize() {
     return totalStaticBloomSize;
   }
 
   @Override
   public long getNumMutationsWithoutWAL() {
     return numMutationsWithoutWAL;
   }
 
   @Override
   public long getDataInMemoryWithoutWAL() {
     return dataInMemoryWithoutWAL;
   }
 
   @Override
   public double getPercentFileLocal() {
     return percentFileLocal;
   }
 
   @Override
   public double getPercentFileLocalSecondaryRegions() {
     return percentFileLocalSecondaryRegions;
   }
 
   @Override
   public long getUpdatesBlockedTime() {
     if (this.regionServer.cacheFlusher == null) {
       return 0;
     }
     return this.regionServer.cacheFlusher.getUpdatesBlockedMsHighWater().get();
   }
 
   @Override
   public long getFlushedCellsCount() {
     return flushedCellsCount;
   }
 
   @Override
   public long getCompactedCellsCount() {
     return compactedCellsCount;
   }
 
   @Override
   public long getMajorCompactedCellsCount() {
     return majorCompactedCellsCount;
   }
 
   @Override
   public long getFlushedCellsSize() {
     return flushedCellsSize;
   }
 
   @Override
   public long getCompactedCellsSize() {
     return compactedCellsSize;
   }
 
   @Override
   public long getMajorCompactedCellsSize() {
     return majorCompactedCellsSize;
   }
 
   /**
    * This is the runnable that will be executed on the executor every PERIOD number of seconds
    * It will take metrics/numbers from all of the regions and use them to compute point in
    * time metrics.
    */
   public class RegionServerMetricsWrapperRunnable implements Runnable {
 
     private long lastRan = 0;
     private long lastRequestCount = 0;
     private long lastReadRequestsCount = 0;
     private long lastWriteRequestsCount = 0;
 
     @Override
     synchronized public void run() {
       try {
         initBlockCache();
 
         HDFSBlocksDistribution hdfsBlocksDistribution = new HDFSBlocksDistribution();
         HDFSBlocksDistribution hdfsBlocksDistributionSecondaryRegions =
             new HDFSBlocksDistribution();
 
         long tempNumStores = 0;
         long tempNumStoreFiles = 0;
         long tempMemstoreSize = 0;
         long tempStoreFileSize = 0;
         long tempMaxStoreFileAge = 0;
         long tempNumReferenceFiles = 0;
         long avgAgeNumerator = 0;
         long numHFiles = 0;
         long tempMinStoreFileAge = Long.MAX_VALUE;
         long tempReadRequestsCount = 0;
         long tempWriteRequestsCount = 0;
         long tempCheckAndMutateChecksFailed = 0;
         long tempCheckAndMutateChecksPassed = 0;
         long tempStorefileIndexSize = 0;
         long tempTotalStaticIndexSize = 0;
         long tempTotalStaticBloomSize = 0;
         long tempNumMutationsWithoutWAL = 0;
         long tempDataInMemoryWithoutWAL = 0;
         double tempPercentFileLocal = 0;
         double tempPercentFileLocalSecondaryRegions = 0;
         long tempFlushedCellsCount = 0;
         long tempCompactedCellsCount = 0;
         long tempMajorCompactedCellsCount = 0;
         long tempFlushedCellsSize = 0;
         long tempCompactedCellsSize = 0;
         long tempMajorCompactedCellsSize = 0;
         long tempBlockedRequestsCount = 0L;
 
         int regionCount = 0;
         for (Region r : regionServer.getOnlineRegionsLocalContext()) {
           tempNumMutationsWithoutWAL += r.getNumMutationsWithoutWAL();
           tempDataInMemoryWithoutWAL += r.getDataInMemoryWithoutWAL();
           tempReadRequestsCount += r.getReadRequestsCount();
           tempWriteRequestsCount += r.getWriteRequestsCount();
           tempCheckAndMutateChecksFailed += r.getCheckAndMutateChecksFailed();
           tempCheckAndMutateChecksPassed += r.getCheckAndMutateChecksPassed();
           tempBlockedRequestsCount += r.getBlockedRequestsCount();
           List<Store> storeList = r.getStores();
           tempNumStores += storeList.size();
           for (Store store : storeList) {
             tempNumStoreFiles += store.getStorefilesCount();
             tempMemstoreSize += store.getMemStoreSize();
             tempStoreFileSize += store.getStorefilesSize();
 
             long storeMaxStoreFileAge = store.getMaxStoreFileAge();
             tempMaxStoreFileAge = (storeMaxStoreFileAge > tempMaxStoreFileAge) ?
               storeMaxStoreFileAge : tempMaxStoreFileAge;
 
             long storeMinStoreFileAge = store.getMinStoreFileAge();
             tempMinStoreFileAge = (storeMinStoreFileAge < tempMinStoreFileAge) ?
               storeMinStoreFileAge : tempMinStoreFileAge;
 
             long storeHFiles = store.getNumHFiles();
             avgAgeNumerator += store.getAvgStoreFileAge() * storeHFiles;
             numHFiles += storeHFiles;
             tempNumReferenceFiles += store.getNumReferenceFiles();
 
             tempStorefileIndexSize += store.getStorefilesIndexSize();
             tempTotalStaticBloomSize += store.getTotalStaticBloomSize();
             tempTotalStaticIndexSize += store.getTotalStaticIndexSize();
             tempFlushedCellsCount += store.getFlushedCellsCount();
             tempCompactedCellsCount += store.getCompactedCellsCount();
             tempMajorCompactedCellsCount += store.getMajorCompactedCellsCount();
             tempFlushedCellsSize += store.getFlushedCellsSize();
             tempCompactedCellsSize += store.getCompactedCellsSize();
             tempMajorCompactedCellsSize += store.getMajorCompactedCellsSize();
           }
 
           HDFSBlocksDistribution distro = r.getHDFSBlocksDistribution();
           hdfsBlocksDistribution.add(distro);
           if (r.getRegionInfo().getReplicaId() != HRegionInfo.DEFAULT_REPLICA_ID) {
             hdfsBlocksDistributionSecondaryRegions.add(distro);
           }
           regionCount++;
         }
 
         float localityIndex =
             hdfsBlocksDistribution
                 .getBlockLocalityIndex(regionServer.getServerName().getHostname());
         tempPercentFileLocal = Double.isNaN(tempBlockedRequestsCount) ? 0 : (localityIndex * 100);
 
         float localityIndexSecondaryRegions =
             hdfsBlocksDistributionSecondaryRegions.getBlockLocalityIndex(regionServer
                 .getServerName().getHostname());
         tempPercentFileLocalSecondaryRegions = Double
             .isNaN(localityIndexSecondaryRegions) ? 0 : (localityIndexSecondaryRegions * 100);
 
         // Compute the number of requests per second
         long currentTime = EnvironmentEdgeManager.currentTime();
 
         // assume that it took PERIOD seconds to start the executor.
         // this is a guess but it's a pretty good one.
         if (lastRan == 0) {
           lastRan = currentTime - period;
         }
 
         // If we've time traveled keep the last requests per second.
         if ((currentTime - lastRan) > 0) {
           long currentRequestCount = getTotalRequestCount();
           requestsPerSecond =
               (currentRequestCount - lastRequestCount) / ((currentTime - lastRan) / 1000.0);
           lastRequestCount = currentRequestCount;
 
           long intervalReadRequestsCount = tempReadRequestsCount - lastReadRequestsCount;
           long intervalWriteRequestsCount = tempWriteRequestsCount - lastWriteRequestsCount;
 
           double readRequestsRatePerMilliSecond = ((double)intervalReadRequestsCount/
               (double)period);
           double writeRequestsRatePerMilliSecond = ((double)intervalWriteRequestsCount/
               (double)period);
 
           readRequestsRate = readRequestsRatePerMilliSecond * 1000.0;
           writeRequestsRate = writeRequestsRatePerMilliSecond * 1000.0;
 
           lastReadRequestsCount = tempReadRequestsCount;
           lastWriteRequestsCount = tempWriteRequestsCount;
 
         }
         lastRan = currentTime;
 
         WALProvider provider = regionServer.walFactory.getWALProvider();
         WALProvider metaProvider = regionServer.walFactory.getMetaWALProvider();
         numWALFiles =
             (provider == null ? 0 : provider.getNumLogFiles())
                 + (metaProvider == null ? 0 : metaProvider.getNumLogFiles());
         walFileSize =
             (provider == null ? 0 : provider.getLogFileSize())
                 + (provider == null ? 0 : provider.getLogFileSize());
         // Copy over computed values so that no thread sees half computed values.
         numStores = tempNumStores;
         numStoreFiles = tempNumStoreFiles;
         memstoreSize = tempMemstoreSize;
         storeFileSize = tempStoreFileSize;
         maxStoreFileAge = tempMaxStoreFileAge;
         if (regionCount > 0) {
           averageRegionSize = (memstoreSize + storeFileSize) / regionCount;
         }
         if (tempMinStoreFileAge != Long.MAX_VALUE) {
           minStoreFileAge = tempMinStoreFileAge;
         }
 
         if (numHFiles != 0) {
           avgStoreFileAge = avgAgeNumerator / numHFiles;
         }
 
         numReferenceFiles= tempNumReferenceFiles;
         readRequestsCount = tempReadRequestsCount;
         writeRequestsCount = tempWriteRequestsCount;
         checkAndMutateChecksFailed = tempCheckAndMutateChecksFailed;
         checkAndMutateChecksPassed = tempCheckAndMutateChecksPassed;
         storefileIndexSize = tempStorefileIndexSize;
         totalStaticIndexSize = tempTotalStaticIndexSize;
         totalStaticBloomSize = tempTotalStaticBloomSize;
         numMutationsWithoutWAL = tempNumMutationsWithoutWAL;
         dataInMemoryWithoutWAL = tempDataInMemoryWithoutWAL;
         percentFileLocal = tempPercentFileLocal;
         percentFileLocalSecondaryRegions = tempPercentFileLocalSecondaryRegions;
         flushedCellsCount = tempFlushedCellsCount;
         compactedCellsCount = tempCompactedCellsCount;
         majorCompactedCellsCount = tempMajorCompactedCellsCount;
         flushedCellsSize = tempFlushedCellsSize;
         compactedCellsSize = tempCompactedCellsSize;
         majorCompactedCellsSize = tempMajorCompactedCellsSize;
         blockedRequestsCount = tempBlockedRequestsCount;
       } catch (Throwable e) {
         LOG.warn("Caught exception! Will suppress and retry.", e);
       }
     }
   }
 
   @Override
   public long getBlockedRequestsCount() {
     return blockedRequestsCount;
   }
 
   @Override
   public long getAverageRegionSize() {
     return averageRegionSize;
   }
 
   public long getDataMissCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getDataMissCount();
   }
 
   @Override
   public long getLeafIndexMissCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getLeafIndexMissCount();
   }
 
   @Override
   public long getBloomChunkMissCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getBloomChunkMissCount();
   }
 
   @Override
   public long getMetaMissCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getMetaMissCount();
   }
 
   @Override
   public long getRootIndexMissCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getRootIndexMissCount();
   }
 
   @Override
   public long getIntermediateIndexMissCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getIntermediateIndexMissCount();
   }
 
   @Override
   public long getFileInfoMissCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getFileInfoMissCount();
   }
 
   @Override
   public long getGeneralBloomMetaMissCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getGeneralBloomMetaMissCount();
   }
 
   @Override
   public long getDeleteFamilyBloomMissCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getDeleteFamilyBloomMissCount();
   }
 
   @Override
   public long getTrailerMissCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getTrailerMissCount();
   }
 
   @Override
   public long getDataHitCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getDataHitCount();
   }
 
   @Override
   public long getLeafIndexHitCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getLeafIndexHitCount();
   }
 
   @Override
   public long getBloomChunkHitCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getBloomChunkHitCount();
   }
 
   @Override
   public long getMetaHitCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getMetaHitCount();
   }
 
   @Override
   public long getRootIndexHitCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getRootIndexHitCount();
   }
 
   @Override
   public long getIntermediateIndexHitCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getIntermediateIndexHitCount();
   }
 
   @Override
   public long getFileInfoHitCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getFileInfoHitCount();
   }
 
   @Override
   public long getGeneralBloomMetaHitCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getGeneralBloomMetaHitCount();
   }
 
   @Override
   public long getDeleteFamilyBloomHitCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getDeleteFamilyBloomHitCount();
   }
 
   @Override
   public long getTrailerHitCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return cacheStats.getTrailerHitCount();
   }
 }