com.hazelcast.map.impl.query.PartitionScanExecutor Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2020, Hazelcast, Inc. All Rights Reserved.
*
* Licensed 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 com.hazelcast.map.impl.query;
import com.hazelcast.internal.iteration.IterationPointer;
import com.hazelcast.query.Predicate;
import com.hazelcast.query.impl.QueryableEntriesSegment;
import java.util.Collection;
/**
* Responsible for executing a full partition scan for the given partitions.
* May execute the scan in the calling thread or delegate to other thread - it depends on the implementation.
*/
public interface PartitionScanExecutor {
void execute(String mapName, Predicate predicate, Collection partitions, Result result);
/**
* Executes the predicate on a partition chunk. The offset in the partition
* is defined by the {@code pointers} and the soft limit is defined by the
* {@code fetchSize}. The method returns the matched entries and updated
* pointers from which new entries can be fetched which allows for efficient
* iteration of query results.
*
* NOTE
* The iteration may be done when the map is being mutated or when there are
* membership changes. The iterator does not reflect the state when it has
* been constructed - it may return some entries that were added after the
* iteration has started and may not return some entries that were removed
* after iteration has started.
* The iterator will not, however, skip an entry if it has not been changed
* and will not return an entry twice.
*
* @param mapName the map name
* @param predicate the predicate which the entries must match
* @param partitionId the partition which is queried
* @param pointers the pointers defining the state of iteration
* @param fetchSize the soft limit for the number of entries to fetch
* @return entries matching the predicate and a table index from which new
* entries can be fetched
*/
QueryableEntriesSegment execute(
String mapName, Predicate predicate, int partitionId,
IterationPointer[] pointers, int fetchSize);
}