content: /*
   * 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.bookkeeper.bookie.stats;
  
  import static org.apache.bookkeeper.bookie.BookKeeperServerStats.BOOKIE_SCOPE;
  import static org.apache.bookkeeper.bookie.BookKeeperServerStats.CATEGORY_SERVER;
  import static org.apache.bookkeeper.bookie.BookKeeperServerStats.LEDGER_CACHE_NUM_EVICTED_LEDGERS;
  import static org.apache.bookkeeper.bookie.BookKeeperServerStats.PENDING_GET_FILE_INFO;
  import static org.apache.bookkeeper.bookie.BookKeeperServerStats.READ_FILE_INFO_CACHE_SIZE;
  import static org.apache.bookkeeper.bookie.BookKeeperServerStats.WRITE_FILE_INFO_CACHE_SIZE;
  
  import java.util.function.Supplier;
  import lombok.Getter;
  import org.apache.bookkeeper.stats.Counter;
  import org.apache.bookkeeper.stats.Gauge;
  import org.apache.bookkeeper.stats.StatsLogger;
  import org.apache.bookkeeper.stats.annotations.StatsDoc;
  
  /**
   * A umbrella class for {@link org.apache.bookkeeper.bookie.IndexPersistenceMgr} stats.
   */
  @StatsDoc(
      name = BOOKIE_SCOPE,
      category = CATEGORY_SERVER,
      help = "Index Persistence Manager related stats"
  )
  @Getter
  public class IndexPersistenceMgrStats {
  
      // Stats
      @StatsDoc(
          name = LEDGER_CACHE_NUM_EVICTED_LEDGERS,
          help = "Number of ledgers evicted from ledger caches"
      )
      private final Counter evictedLedgersCounter;
      @StatsDoc(
          name = PENDING_GET_FILE_INFO,
          help = "Number of pending get-file-info requests"
      )
      private final Counter pendingGetFileInfoCounter;
      @StatsDoc(
          name = WRITE_FILE_INFO_CACHE_SIZE,
          help = "Current write file info cache size"
      )
      private final Gauge<Number> writeFileInfoCacheSizeGauge;
      @StatsDoc(
          name = READ_FILE_INFO_CACHE_SIZE,
          help = "Current read file info cache size"
      )
      private final Gauge<Number> readFileInfoCacheSizeGauge;
  
      public IndexPersistenceMgrStats(StatsLogger statsLogger,
                                      Supplier<Number> writeFileInfoCacheSizeSupplier,
                                      Supplier<Number> readFileInfoCacheSizeSupplier) {
          evictedLedgersCounter = statsLogger.getCounter(LEDGER_CACHE_NUM_EVICTED_LEDGERS);
          pendingGetFileInfoCounter = statsLogger.getCounter(PENDING_GET_FILE_INFO);
          writeFileInfoCacheSizeGauge = new Gauge<Number>() {
              @Override
              public Number getDefaultValue() {
                  return 0;
              }
  
              @Override
              public Number getSample() {
                  return writeFileInfoCacheSizeSupplier.get();
              }
          };
          statsLogger.registerGauge(WRITE_FILE_INFO_CACHE_SIZE, writeFileInfoCacheSizeGauge);
          readFileInfoCacheSizeGauge = new Gauge<Number>() {
              @Override
              public Number getDefaultValue() {
                  return 0;
              }
  
              @Override
              public Number getSample() {
                  return readFileInfoCacheSizeSupplier.get();
              }
          };
          statsLogger.registerGauge(READ_FILE_INFO_CACHE_SIZE, readFileInfoCacheSizeGauge);
      }
  
  
  }
  