PartitionScanRunner.java example

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/*
 * Copyright (c) 2008-2017, 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.config.CacheDeserializedValues;
import com.hazelcast.internal.cluster.ClusterService;
import com.hazelcast.internal.serialization.InternalSerializationService;
import com.hazelcast.logging.ILogger;
import com.hazelcast.map.impl.MapContainer;
import com.hazelcast.map.impl.MapServiceContext;
import com.hazelcast.map.impl.PartitionContainer;
import com.hazelcast.map.impl.record.Record;
import com.hazelcast.map.impl.record.Records;
import com.hazelcast.nio.serialization.Data;
import com.hazelcast.query.PagingPredicate;
import com.hazelcast.query.Predicate;
import com.hazelcast.query.impl.CachedQueryEntry;
import com.hazelcast.query.impl.QueryableEntry;
import com.hazelcast.query.impl.getters.Extractors;
import com.hazelcast.spi.NodeEngine;
import com.hazelcast.spi.OperationService;
import com.hazelcast.spi.partition.IPartitionService;
import com.hazelcast.util.Clock;

import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import static com.hazelcast.query.PagingPredicateAccessor.getNearestAnchorEntry;
import static com.hazelcast.util.SortingUtil.compareAnchor;
import static com.hazelcast.util.SortingUtil.getSortedSubList;

/**
 * Responsible for running a full-partition scna for a single partition in the calling thread.
 */
public class PartitionScanRunner {

    protected final MapServiceContext mapServiceContext;
    protected final NodeEngine nodeEngine;
    protected final ILogger logger;
    protected final InternalSerializationService serializationService;
    protected final IPartitionService partitionService;
    protected final OperationService operationService;
    protected final ClusterService clusterService;

    public PartitionScanRunner(MapServiceContext mapServiceContext) {
        this.mapServiceContext = mapServiceContext;
        this.nodeEngine = mapServiceContext.getNodeEngine();
        this.serializationService = (InternalSerializationService) nodeEngine.getSerializationService();
        this.partitionService = nodeEngine.getPartitionService();
        this.logger = nodeEngine.getLogger(getClass());
        this.operationService = nodeEngine.getOperationService();
        this.clusterService = nodeEngine.getClusterService();
    }

    @SuppressWarnings("unchecked")
    public Collection<QueryableEntry> run(String mapName, Predicate predicate, int partitionId) {
        PagingPredicate pagingPredicate = predicate instanceof PagingPredicate ? (PagingPredicate) predicate : null;
        List<QueryableEntry> resultList = new LinkedList<QueryableEntry>();

        PartitionContainer partitionContainer = mapServiceContext.getPartitionContainer(partitionId);
        MapContainer mapContainer = mapServiceContext.getMapContainer(mapName);
        Iterator<Record> iterator = partitionContainer.getRecordStore(mapName).loadAwareIterator(getNow(), false);
        Map.Entry<Integer, Map.Entry> nearestAnchorEntry = getNearestAnchorEntry(pagingPredicate);
        boolean useCachedValues = isUseCachedDeserializedValuesEnabled(mapContainer);
        Extractors extractors = mapServiceContext.getExtractors(mapName);
        while (iterator.hasNext()) {
            Record record = iterator.next();
            Data key = (Data) toData(record.getKey());
            Object value = toData(
                    useCachedValues ? Records.getValueOrCachedValue(record, serializationService) : record.getValue());
            if (value == null) {
                continue;
            }
            //we want to always use CachedQueryEntry as these are short-living objects anyway
            QueryableEntry queryEntry = new CachedQueryEntry(serializationService, key, value, extractors);

            if (predicate.apply(queryEntry) && compareAnchor(pagingPredicate, queryEntry, nearestAnchorEntry)) {
                resultList.add(queryEntry);
            }
        }
        return getSortedSubList(resultList, pagingPredicate, nearestAnchorEntry);
    }

    protected boolean isUseCachedDeserializedValuesEnabled(MapContainer mapContainer) {
        CacheDeserializedValues cacheDeserializedValues = mapContainer.getMapConfig().getCacheDeserializedValues();
        switch (cacheDeserializedValues) {
            case NEVER:
                return false;
            case ALWAYS:
                return true;
            default:
                //if index exists then cached value is already set -> let's use it
                return mapContainer.getIndexes().hasIndex();
        }
    }

    protected <T> Object toData(T input) {
        return input;
    }

    protected long getNow() {
        return Clock.currentTimeMillis();
    }
}