io.druid.query.datasourcemetadata.DataSourceQueryQueryToolChest.java Source code

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Here is the source code for io.druid.query.datasourcemetadata.DataSourceQueryQueryToolChest.java

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/*
 * Druid - a distributed column store.
 * Copyright 2012 - 2015 Metamarkets Group Inc.
 *
 * 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 io.druid.query.datasourcemetadata;

import com.fasterxml.jackson.core.type.TypeReference;
import com.google.common.base.Function;
import com.google.common.base.Functions;
import com.google.common.base.Predicate;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.common.collect.Ordering;
import com.metamx.common.guava.MergeSequence;
import com.metamx.common.guava.Sequence;
import com.metamx.common.guava.Sequences;
import com.metamx.emitter.service.ServiceMetricEvent;
import io.druid.collections.OrderedMergeSequence;
import io.druid.query.BySegmentSkippingQueryRunner;
import io.druid.query.CacheStrategy;
import io.druid.query.DataSourceUtil;
import io.druid.query.Query;
import io.druid.query.QueryRunner;
import io.druid.query.QueryToolChest;
import io.druid.query.Result;
import io.druid.query.aggregation.MetricManipulationFn;
import io.druid.timeline.LogicalSegment;

import java.util.List;
import java.util.Map;

/**
 */
public class DataSourceQueryQueryToolChest
        extends QueryToolChest<Result<DataSourceMetadataResultValue>, DataSourceMetadataQuery> {
    private static final TypeReference<Result<DataSourceMetadataResultValue>> TYPE_REFERENCE = new TypeReference<Result<DataSourceMetadataResultValue>>() {
    };

    @Override
    public <T extends LogicalSegment> List<T> filterSegments(DataSourceMetadataQuery query, List<T> segments) {
        if (segments.size() <= 1) {
            return segments;
        }

        final T max = segments.get(segments.size() - 1);

        return Lists.newArrayList(Iterables.filter(segments, new Predicate<T>() {
            @Override
            public boolean apply(T input) {
                return max != null && input.getInterval().overlaps(max.getInterval());
            }
        }));
    }

    @Override
    public QueryRunner<Result<DataSourceMetadataResultValue>> mergeResults(
            final QueryRunner<Result<DataSourceMetadataResultValue>> runner) {
        return new BySegmentSkippingQueryRunner<Result<DataSourceMetadataResultValue>>(runner) {
            @Override
            protected Sequence<Result<DataSourceMetadataResultValue>> doRun(
                    QueryRunner<Result<DataSourceMetadataResultValue>> baseRunner,
                    Query<Result<DataSourceMetadataResultValue>> input, Map<String, Object> context) {
                DataSourceMetadataQuery query = (DataSourceMetadataQuery) input;
                return Sequences.simple(query.mergeResults(Sequences.toList(baseRunner.run(query, context),
                        Lists.<Result<DataSourceMetadataResultValue>>newArrayList())));
            }
        };
    }

    @Override
    public Sequence<Result<DataSourceMetadataResultValue>> mergeSequences(
            Sequence<Sequence<Result<DataSourceMetadataResultValue>>> seqOfSequences) {
        return new OrderedMergeSequence<>(getOrdering(), seqOfSequences);
    }

    @Override
    public Sequence<Result<DataSourceMetadataResultValue>> mergeSequencesUnordered(
            Sequence<Sequence<Result<DataSourceMetadataResultValue>>> seqOfSequences) {
        return new MergeSequence<>(getOrdering(), seqOfSequences);
    }

    @Override
    public ServiceMetricEvent.Builder makeMetricBuilder(DataSourceMetadataQuery query) {
        return new ServiceMetricEvent.Builder()
                .setDimension("dataSource", DataSourceUtil.getMetricName(query.getDataSource()))
                .setDimension("type", query.getType());
    }

    @Override
    public Function<Result<DataSourceMetadataResultValue>, Result<DataSourceMetadataResultValue>> makePreComputeManipulatorFn(
            DataSourceMetadataQuery query, MetricManipulationFn fn) {
        return Functions.identity();
    }

    @Override
    public TypeReference<Result<DataSourceMetadataResultValue>> getResultTypeReference() {
        return TYPE_REFERENCE;
    }

    @Override
    public CacheStrategy getCacheStrategy(DataSourceMetadataQuery query) {
        return null;
    }

    public Ordering<Result<DataSourceMetadataResultValue>> getOrdering() {
        return Ordering.natural();
    }
}