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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.
*/
package org.elasticsearch.search.aggregations.pipeline;
import org.elasticsearch.common.ParseField;
import org.elasticsearch.common.ParsingException;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.xcontent.XContentLocation;
import org.elasticsearch.index.query.QueryParseContext;
import org.elasticsearch.search.aggregations.AggregationExecutionException;
import org.elasticsearch.search.aggregations.InternalMultiBucketAggregation;
import org.elasticsearch.search.aggregations.InvalidAggregationPathException;
import org.elasticsearch.search.aggregations.bucket.MultiBucketsAggregation;
import org.elasticsearch.search.aggregations.metrics.InternalNumericMetricsAggregation;
import org.elasticsearch.search.aggregations.support.AggregationPath;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* A set of static helpers to simplify working with aggregation buckets, in
* particular providing utilities that help pipeline aggregations.
*/
public class BucketHelpers {
/**
* A gap policy determines how "holes" in a set of buckets should be handled. For example,
* a date_histogram might have empty buckets due to no data existing for that time interval.
* This can cause problems for operations like a derivative, which relies on a continuous
* function.
*
* "insert_zeros": empty buckets will be filled with zeros for all metrics
* "ignore": empty buckets will simply be ignored
*/
public enum GapPolicy {
INSERT_ZEROS((byte) 0, "insert_zeros"), SKIP((byte) 1, "skip");
/**
* Parse a string GapPolicy into the byte enum
*
* @param context SearchContext this is taking place in
* @param text GapPolicy in string format (e.g. "ignore")
* @return GapPolicy enum
*/
public static GapPolicy parse(QueryParseContext context, String text, XContentLocation tokenLocation) {
GapPolicy result = null;
for (GapPolicy policy : values()) {
if (policy.parseField.match(text)) {
if (result == null) {
result = policy;
} else {
throw new IllegalStateException("Text can be parsed to 2 different gap policies: text=[" + text
+ "], " + "policies=" + Arrays.asList(result, policy));
}
}
}
if (result == null) {
final List<String> validNames = new ArrayList<>();
for (GapPolicy policy : values()) {
validNames.add(policy.getName());
}
throw new ParsingException(tokenLocation, "Invalid gap policy: [" + text + "], accepted values: " + validNames);
}
return result;
}
private final byte id;
private final ParseField parseField;
GapPolicy(byte id, String name) {
this.id = id;
this.parseField = new ParseField(name);
}
/**
* Serialize the GapPolicy to the output stream
*/
public void writeTo(StreamOutput out) throws IOException {
out.writeByte(id);
}
/**
* Deserialize the GapPolicy from the input stream
*
* @return GapPolicy Enum
*/
public static GapPolicy readFrom(StreamInput in) throws IOException {
byte id = in.readByte();
for (GapPolicy gapPolicy : values()) {
if (id == gapPolicy.id) {
return gapPolicy;
}
}
throw new IllegalStateException("Unknown GapPolicy with id [" + id + "]");
}
/**
* Return the english-formatted name of the GapPolicy
*
* @return English representation of GapPolicy
*/
public String getName() {
return parseField.getPreferredName();
}
}
/**
* Given a path and a set of buckets, this method will return the value
* inside the agg at that path. This is used to extract values for use by
* pipeline aggregations (e.g. a derivative might need the price for each
* bucket). If the bucket is empty, the configured GapPolicy is invoked to
* resolve the missing bucket
*
* @param agg
* A series of agg buckets in the form of a histogram
* @param bucket
* A specific bucket that a value needs to be extracted from.
* This bucket should be present in the <code>histo</code>
* parameter
* @param aggPath
* The path to a particular value that needs to be extracted.
* This path should point to a metric inside the
* <code>bucket</code>
* @param gapPolicy
* The gap policy to apply if empty buckets are found
* @return The value extracted from <code>bucket</code> found at
* <code>aggPath</code>
*/
public static Double resolveBucketValue(MultiBucketsAggregation agg,
InternalMultiBucketAggregation.InternalBucket bucket, String aggPath, GapPolicy gapPolicy) {
List<String> aggPathsList = AggregationPath.parse(aggPath).getPathElementsAsStringList();
return resolveBucketValue(agg, bucket, aggPathsList, gapPolicy);
}
public static Double resolveBucketValue(MultiBucketsAggregation agg,
InternalMultiBucketAggregation.InternalBucket bucket, List<String> aggPathAsList, GapPolicy gapPolicy) {
try {
Object propertyValue = bucket.getProperty(agg.getName(), aggPathAsList);
if (propertyValue == null) {
throw new AggregationExecutionException(AbstractPipelineAggregationBuilder.BUCKETS_PATH_FIELD.getPreferredName()
+ " must reference either a number value or a single value numeric metric aggregation");
} else {
double value;
if (propertyValue instanceof Number) {
value = ((Number) propertyValue).doubleValue();
} else if (propertyValue instanceof InternalNumericMetricsAggregation.SingleValue) {
value = ((InternalNumericMetricsAggregation.SingleValue) propertyValue).value();
} else {
throw new AggregationExecutionException(AbstractPipelineAggregationBuilder.BUCKETS_PATH_FIELD.getPreferredName()
+ " must reference either a number value or a single value numeric metric aggregation, got: "
+ propertyValue.getClass().getCanonicalName());
}
// doc count never has missing values so gap policy doesn't apply here
boolean isDocCountProperty = aggPathAsList.size() == 1 && "_count".equals(aggPathAsList.get(0));
if (Double.isInfinite(value) || Double.isNaN(value) || (bucket.getDocCount() == 0 && !isDocCountProperty)) {
switch (gapPolicy) {
case INSERT_ZEROS:
return 0.0;
case SKIP:
default:
return Double.NaN;
}
} else {
return value;
}
}
} catch (InvalidAggregationPathException e) {
return null;
}
}
}