com.metamx.druid.query.IntervalChunkingQueryRunner.java Source code

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Here is the source code for com.metamx.druid.query.IntervalChunkingQueryRunner.java

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/*
 * Druid - a distributed column store.
 * Copyright (C) 2012  Metamarkets Group Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package com.metamx.druid.query;

import com.google.common.base.Function;
import com.google.common.collect.Lists;
import com.metamx.common.guava.FunctionalIterable;
import com.metamx.common.guava.Sequence;
import com.metamx.common.guava.Sequences;
import com.metamx.druid.PeriodGranularity;
import com.metamx.druid.Query;
import com.metamx.druid.query.segment.MultipleIntervalSegmentSpec;
import org.joda.time.Interval;
import org.joda.time.Period;

import javax.annotation.Nullable;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;

/**
 */
public class IntervalChunkingQueryRunner<T> implements QueryRunner<T> {
    private final QueryRunner<T> baseRunner;
    private final Period period;

    public IntervalChunkingQueryRunner(QueryRunner<T> baseRunner, Period period) {
        this.baseRunner = baseRunner;
        this.period = period;
    }

    @Override
    public Sequence<T> run(final Query<T> query) {
        return Sequences.concat(FunctionalIterable.create(query.getIntervals())
                .transformCat(new Function<Interval, Iterable<Interval>>() {
                    @Override
                    public Iterable<Interval> apply(@Nullable Interval input) {
                        return splitInterval(input);
                    }
                }).transform(new Function<Interval, Sequence<T>>() {
                    @Override
                    public Sequence<T> apply(Interval singleInterval) {
                        return baseRunner.run(query.withQuerySegmentSpec(
                                new MultipleIntervalSegmentSpec(Arrays.asList(singleInterval))));
                    }
                }));
    }

    private Iterable<Interval> splitInterval(Interval interval) {
        if (interval.getEndMillis() == interval.getStartMillis()) {
            return Lists.newArrayList(interval);
        }

        List<Interval> intervals = Lists.newArrayList();
        Iterator<Long> timestamps = new PeriodGranularity(period, null, null)
                .iterable(interval.getStartMillis(), interval.getEndMillis()).iterator();

        long start = Math.max(timestamps.next(), interval.getStartMillis());
        while (timestamps.hasNext()) {
            long end = timestamps.next();
            intervals.add(new Interval(start, end));
            start = end;
        }

        if (start < interval.getEndMillis()) {
            intervals.add(new Interval(start, interval.getEndMillis()));
        }

        return intervals;
    }
}