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.notifications;
  
  import java.util.Optional;
  
  import javax.annotation.Nullable;
  
  import org.apache.cassandra.db.memtable.Memtable;
  import org.apache.cassandra.io.sstable.format.SSTableReader;
  
  /**
   * Notification sent after SSTables are added to their {@link org.apache.cassandra.db.ColumnFamilyStore}.
   */
  public class SSTableAddedNotification implements INotification
  {
      /** The added SSTables */
      public final Iterable<SSTableReader> added;
  
      /** The memtable from which the tables come when they have been added due to a flush, {@code null} otherwise. */
      @Nullable
      private final Memtable memtable;
  
      /**
       * Creates a new {@code SSTableAddedNotification} for the specified SSTables and optional memtable.
       *
       * @param added    the added SSTables
       * @param memtable the memtable from which the tables come when they have been added due to a memtable flush,
       *                 or {@code null} if they don't come from a flush
       */
      public SSTableAddedNotification(Iterable<SSTableReader> added, @Nullable Memtable memtable)
      {
          this.added = added;
          this.memtable = memtable;
      }
  
      /**
       * Returns the memtable from which the tables come when they have been added due to a memtable flush. If not, an
       * empty Optional should be returned.
       *
       * @return the origin memtable in case of a flush, {@link Optional#empty()} otherwise
       */
      public Optional<Memtable> memtable()
      {
          return Optional.ofNullable(memtable);
      }
  }
  