io.druid.query.select.SelectResultValueBuilder Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of druid-processing Show documentation
Show all versions of druid-processing Show documentation
A module that is everything required to understands Druid Segments
/*
* Licensed to Metamarkets Group Inc. (Metamarkets) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Metamarkets licenses this file
* to you 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.select;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.MinMaxPriorityQueue;
import com.google.common.collect.Queues;
import com.google.common.primitives.Longs;
import com.metamx.common.guava.Comparators;
import io.druid.query.Result;
import org.joda.time.DateTime;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.Queue;
/**
*/
public class SelectResultValueBuilder
{
private static final Comparator comparator = new Comparator()
{
@Override
public int compare(EventHolder o1, EventHolder o2)
{
int retVal = Longs.compare(o1.getTimestamp().getMillis(), o2.getTimestamp().getMillis());
if (retVal == 0) {
retVal = o1.getSegmentId().compareTo(o2.getSegmentId());
}
if (retVal == 0) {
retVal = Integer.compare(o1.getOffset(), o2.getOffset());
}
return retVal;
}
};
private final DateTime timestamp;
private final PagingSpec pagingSpec;
private Queue pQueue = null;
public SelectResultValueBuilder(
DateTime timestamp,
PagingSpec pagingSpec,
boolean descending
)
{
this.timestamp = timestamp;
this.pagingSpec = pagingSpec;
instantiatePQueue(pagingSpec.getThreshold(), descending ? Comparators.inverse(comparator) : comparator);
}
public void addEntry(
EventHolder event
)
{
pQueue.add(event);
}
public Result build()
{
// Pull out top aggregated values
List values = Lists.newArrayListWithCapacity(pQueue.size());
Map pagingIdentifiers = Maps.newLinkedHashMap();
while (!pQueue.isEmpty()) {
EventHolder event = pQueue.remove();
pagingIdentifiers.put(event.getSegmentId(), event.getOffset());
values.add(event);
}
if (pagingIdentifiers.isEmpty()) {
pagingIdentifiers.putAll(pagingSpec.getPagingIdentifiers());
}
return new Result(
timestamp,
new SelectResultValue(pagingIdentifiers, values)
);
}
private void instantiatePQueue(int threshold, final Comparator comparator)
{
this.pQueue = threshold > 0
? MinMaxPriorityQueue.orderedBy(comparator).maximumSize(threshold).create()
: Queues.newArrayDeque();
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy