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.cassandra.metrics;
  
  import com.codahale.metrics.Gauge;
  import com.codahale.metrics.Meter;
  import org.apache.cassandra.utils.memory.BufferPool;
  
  import static org.apache.cassandra.metrics.CassandraMetricsRegistry.Metrics;
  
  public class BufferPoolMetrics
  {
      public static final String TYPE_NAME = "BufferPool";
      /** Total number of hits */
      public final Meter hits;
  
      /** Total number of misses */
      public final Meter misses;
  
      /** Total threshold for a certain type of buffer pool*/
      public final Gauge<Long> capacity;
  
      /** Total size of buffer pools, in bytes, including overflow allocation */
      public final Gauge<Long> size;
  
      /** Total size, in bytes, of active buffered being used from the pool currently + overflow */
      public final Gauge<Long> usedSize;
  
      /**
       * Total size, in bytes, of direct or heap buffers allocated by the pool but not part of the pool
       * either because they are too large to fit or because the pool has exceeded its maximum limit or because it's
       * on-heap allocation.
       */
      public final Gauge<Long> overflowSize;
  
      public BufferPoolMetrics(String scope, BufferPool bufferPool)
      {
          MetricNameFactory factory = new DefaultNameFactory(TYPE_NAME, scope);
  
          hits = Metrics.meter(factory.createMetricName("Hits"));
  
          misses = Metrics.meter(factory.createMetricName("Misses"));
  
          capacity = Metrics.register(factory.createMetricName("Capacity"), bufferPool::memoryUsageThreshold);
  
          overflowSize = Metrics.register(factory.createMetricName("OverflowSize"), bufferPool::overflowMemoryInBytes);
  
          usedSize = Metrics.register(factory.createMetricName("UsedSize"), bufferPool::usedSizeInBytes);
  
          size = Metrics.register(factory.createMetricName("Size"), bufferPool::sizeInBytes);
      }
  
  }
  