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* Licensed to Elasticsearch under one or more contributor
* 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.derivative;
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.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 DerivativePipelineAggregator extends PipelineAggregator {
private final DocValueFormat formatter;
private final GapPolicy gapPolicy;
private final Double xAxisUnits;
public DerivativePipelineAggregator(String name, String[] bucketsPaths, DocValueFormat formatter, GapPolicy gapPolicy, Long xAxisUnits,
Map<String, Object> metadata) {
super(name, bucketsPaths, metadata);
this.formatter = formatter;
this.gapPolicy = gapPolicy;
this.xAxisUnits = xAxisUnits == null ? null : (double) xAxisUnits;
}
/**
* Read from a stream.
*/
public DerivativePipelineAggregator(StreamInput in) throws IOException {
super(in);
formatter = in.readNamedWriteable(DocValueFormat.class);
gapPolicy = GapPolicy.readFrom(in);
xAxisUnits = in.readOptionalDouble();
}
@Override
public void doWriteTo(StreamOutput out) throws IOException {
out.writeNamedWriteable(formatter);
gapPolicy.writeTo(out);
out.writeOptionalDouble(xAxisUnits);
}
@Override
public String getWriteableName() {
return DerivativePipelineAggregationBuilder.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<>();
Number lastBucketKey = null;
Double lastBucketValue = null;
for (InternalMultiBucketAggregation.InternalBucket bucket : buckets) {
Number thisBucketKey = factory.getKey(bucket);
Double thisBucketValue = resolveBucketValue(histo, bucket, bucketsPaths()[0], gapPolicy);
if (lastBucketValue != null && thisBucketValue != null) {
double gradient = thisBucketValue - lastBucketValue;
double xDiff = -1;
if (xAxisUnits != null) {
xDiff = (thisBucketKey.doubleValue() - lastBucketKey.doubleValue()) / xAxisUnits;
}
final List<InternalAggregation> aggs = StreamSupport.stream(bucket.getAggregations().spliterator(), false).map((p) -> {
return (InternalAggregation) p;
}).collect(Collectors.toList());
aggs.add(new InternalDerivative(name(), gradient, xDiff, formatter, new ArrayList<PipelineAggregator>(), metaData()));
Bucket newBucket = factory.createBucket(factory.getKey(bucket), bucket.getDocCount(), new InternalAggregations(aggs));
newBuckets.add(newBucket);
} else {
newBuckets.add(bucket);
}
lastBucketKey = thisBucketKey;
lastBucketValue = thisBucketValue;
}
return factory.createAggregation(newBuckets);
}
}