/*
 * 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.
/**
 * 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(){}
    };
}