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.cache;
  
  import java.util.concurrent.atomic.AtomicLong;
  
  import com.google.common.base.Objects;
  
  /**
   * A sentinel object for row caches.  See comments to getThroughCache and CASSANDRA-3862.
   */
  public class RowCacheSentinel implements IRowCacheEntry
  {
      private static final AtomicLong generator = new AtomicLong();
  
      final long sentinelId;
  
      public RowCacheSentinel()
      {
          sentinelId = generator.getAndIncrement();
      }
  
      RowCacheSentinel(long sentinelId)
      {
          this.sentinelId = sentinelId;
      }
  
      @Override
      public boolean equals(Object o)
      {
          if (!(o instanceof RowCacheSentinel)) return false;
  
          RowCacheSentinel other = (RowCacheSentinel) o;
          return this.sentinelId == other.sentinelId;
      }
  
      @Override
      public int hashCode()
      {
          return Objects.hashCode(sentinelId);
      }
  }
  