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* 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
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package org.elasticsearch.search.aggregations.pipeline.serialdiff;
import com.google.common.collect.EvictingQueue;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.InternalAggregation.ReduceContext;
import org.elasticsearch.search.aggregations.InternalAggregation.Type;
import org.elasticsearch.search.aggregations.InternalAggregations;
import org.elasticsearch.search.aggregations.bucket.histogram.InternalHistogram;
import org.elasticsearch.search.aggregations.pipeline.InternalSimpleValue;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregatorFactory;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregatorStreams;
import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
import org.elasticsearch.search.aggregations.support.format.ValueFormatterStreams;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import static org.elasticsearch.common.util.CollectionUtils.eagerTransform;
import static org.elasticsearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
import static org.elasticsearch.search.aggregations.pipeline.BucketHelpers.resolveBucketValue;
public class SerialDiffPipelineAggregator extends PipelineAggregator {
public final static Type TYPE = new Type("serial_diff");
public final static PipelineAggregatorStreams.Stream STREAM = new PipelineAggregatorStreams.Stream() {
@Override
public SerialDiffPipelineAggregator readResult(StreamInput in) throws IOException {
SerialDiffPipelineAggregator result = new SerialDiffPipelineAggregator();
result.readFrom(in);
return result;
}
};
public static void registerStreams() {
PipelineAggregatorStreams.registerStream(STREAM, TYPE.stream());
}
private ValueFormatter formatter;
private GapPolicy gapPolicy;
private int lag;
public SerialDiffPipelineAggregator() {
}
public SerialDiffPipelineAggregator(String name, String[] bucketsPaths, @Nullable ValueFormatter formatter, GapPolicy gapPolicy,
int lag, Map<String, Object> metadata) {
super(name, bucketsPaths, metadata);
this.formatter = formatter;
this.gapPolicy = gapPolicy;
this.lag = lag;
}
@Override
public Type type() {
return TYPE;
}
@Override
public InternalAggregation reduce(InternalAggregation aggregation, ReduceContext reduceContext) {
InternalHistogram histo = (InternalHistogram) aggregation;
List<? extends InternalHistogram.Bucket> buckets = histo.getBuckets();
InternalHistogram.Factory<? extends InternalHistogram.Bucket> factory = histo.getFactory();
List newBuckets = new ArrayList<>();
EvictingQueue<Double> lagWindow = EvictingQueue.create(lag);
int counter = 0;
for (InternalHistogram.Bucket bucket : buckets) {
Double thisBucketValue = resolveBucketValue(histo, bucket, bucketsPaths()[0], gapPolicy);
InternalHistogram.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 = new ArrayList<>(eagerTransform(bucket.getAggregations().asList(), AGGREGATION_TRANFORM_FUNCTION));
aggs.add(new InternalSimpleValue(name(), diff, formatter, new ArrayList<PipelineAggregator>(), metaData()));
newBucket = factory.createBucket(bucket.getKey(), bucket.getDocCount(), new InternalAggregations(
aggs), bucket.getKeyed(), bucket.getFormatter());
}
newBuckets.add(newBucket);
lagWindow.add(thisBucketValue);
}
return factory.create(newBuckets, histo);
}
@Override
public void doReadFrom(StreamInput in) throws IOException {
formatter = ValueFormatterStreams.readOptional(in);
gapPolicy = GapPolicy.readFrom(in);
lag = in.readVInt();
}
@Override
public void doWriteTo(StreamOutput out) throws IOException {
ValueFormatterStreams.writeOptional(formatter, out);
gapPolicy.writeTo(out);
out.writeVInt(lag);
}
public static class Factory extends PipelineAggregatorFactory {
private final ValueFormatter formatter;
private GapPolicy gapPolicy;
private int lag;
public Factory(String name, String[] bucketsPaths, @Nullable ValueFormatter formatter, GapPolicy gapPolicy, int lag) {
super(name, TYPE.name(), bucketsPaths);
this.formatter = formatter;
this.gapPolicy = gapPolicy;
this.lag = lag;
}
@Override
protected PipelineAggregator createInternal(Map<String, Object> metaData) throws IOException {
return new SerialDiffPipelineAggregator(name, bucketsPaths, formatter, gapPolicy, lag, metaData);
}
}
}