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.index.transactions;
  
  import org.apache.cassandra.db.DeletionTime;
  import org.apache.cassandra.db.rows.Row;
  
  /**
   * Performs garbage collection of index entries during a cleanup.
   *
   * Notifies registered indexers of each partition being removed and
   *
   * Compaction and Cleanup are somewhat simpler than dealing with incoming writes,
   * being only concerned with cleaning up stale index entries.
   *
   * When multiple versions of a row are compacted, the CleanupTransaction is
   * notified of the versions being merged, which it diffs against the merge result
   * and forwards to the registered Index.Indexer instances when on commit.
   *
   * Instances are currently scoped to a single row within a partition, but this could be improved to batch process
   * multiple rows within a single partition.
   */
  public interface CleanupTransaction extends IndexTransaction
  {
  
      void onPartitionDeletion(DeletionTime deletionTime);
      void onRowDelete(Row row);
  
      CleanupTransaction NO_OP = new CleanupTransaction()
      {
          public void start(){}
          public void onPartitionDeletion(DeletionTime deletionTime){}
          public void onRowDelete(Row row){}
          public void commit(){}
      };
  }
  