/*
* Druid - a distributed column store.
* Copyright (C) 2012, 2013 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 io.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 io.druid.granularity.PeriodGranularity;
import io.druid.query.spec.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;
import java.util.Map;
/**
*/
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, final Map<String, Object> context)
{
if (period.getMillis() == 0) {
return baseRunner.run(query, context);
}
return Sequences.concat(
FunctionalIterable
.create(query.getIntervals())
.transformCat(
new Function<Interval, Iterable<Interval>>()
{
@Override
public Iterable<Interval> apply(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))),
context
);
}
}
)
);
}
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;
}
}