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* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.
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package org.elasticsearch.search.aggregations.pipeline.serialdiff;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.collect.EvictingQueue;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.search.DocValueFormat;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.InternalAggregation.ReduceContext;
import org.elasticsearch.search.aggregations.InternalAggregations;
import org.elasticsearch.search.aggregations.InternalMultiBucketAggregation;
import org.elasticsearch.search.aggregations.bucket.MultiBucketsAggregation.Bucket;
import org.elasticsearch.search.aggregations.bucket.histogram.HistogramFactory;
import org.elasticsearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
import org.elasticsearch.search.aggregations.pipeline.InternalSimpleValue;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;
import static org.elasticsearch.search.aggregations.pipeline.BucketHelpers.resolveBucketValue;
public class SerialDiffPipelineAggregator extends PipelineAggregator {
private DocValueFormat formatter;
private GapPolicy gapPolicy;
private int lag;
public SerialDiffPipelineAggregator(String name, String[] bucketsPaths, @Nullable DocValueFormat formatter, GapPolicy gapPolicy,
int lag, Map<String, Object> metadata) {
super(name, bucketsPaths, metadata);
this.formatter = formatter;
this.gapPolicy = gapPolicy;
this.lag = lag;
}
/**
* Read from a stream.
*/
public SerialDiffPipelineAggregator(StreamInput in) throws IOException {
super(in);
formatter = in.readNamedWriteable(DocValueFormat.class);
gapPolicy = GapPolicy.readFrom(in);
lag = in.readVInt();
}
@Override
public void doWriteTo(StreamOutput out) throws IOException {
out.writeNamedWriteable(formatter);
gapPolicy.writeTo(out);
out.writeVInt(lag);
}
@Override
public String getWriteableName() {
return SerialDiffPipelineAggregationBuilder.NAME;
}
@Override
public InternalAggregation reduce(InternalAggregation aggregation, ReduceContext reduceContext) {
InternalMultiBucketAggregation<? extends InternalMultiBucketAggregation, ? extends InternalMultiBucketAggregation.InternalBucket>
histo = (InternalMultiBucketAggregation<? extends InternalMultiBucketAggregation, ? extends
InternalMultiBucketAggregation.InternalBucket>) aggregation;
List<? extends InternalMultiBucketAggregation.InternalBucket> buckets = histo.getBuckets();
HistogramFactory factory = (HistogramFactory) histo;
List<Bucket> newBuckets = new ArrayList<>();
EvictingQueue<Double> lagWindow = new EvictingQueue<>(lag);
int counter = 0;
for (InternalMultiBucketAggregation.InternalBucket bucket : buckets) {
Double thisBucketValue = resolveBucketValue(histo, bucket, bucketsPaths()[0], gapPolicy);
Bucket newBucket = bucket;
counter += 1;
// Still under the initial lag period, add nothing and move on
Double lagValue;
if (counter <= lag) {
lagValue = Double.NaN;
} else {
lagValue = lagWindow.peek(); // Peek here, because we rely on add'ing to always move the window
}
// Normalize null's to NaN
if (thisBucketValue == null) {
thisBucketValue = Double.NaN;
}
// Both have values, calculate diff and replace the "empty" bucket
if (!Double.isNaN(thisBucketValue) && !Double.isNaN(lagValue)) {
double diff = thisBucketValue - lagValue;
List<InternalAggregation> aggs = StreamSupport.stream(bucket.getAggregations().spliterator(), false).map(
(p) -> (InternalAggregation) p).collect(Collectors.toList());
aggs.add(new InternalSimpleValue(name(), diff, formatter, new ArrayList<>(), metaData()));
newBucket = factory.createBucket(factory.getKey(bucket), bucket.getDocCount(), new InternalAggregations(aggs));
}
newBuckets.add(newBucket);
lagWindow.add(thisBucketValue);
}
return factory.createAggregation(newBuckets);
}
}