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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.support;
import org.elasticsearch.common.Strings;
import org.elasticsearch.search.aggregations.Aggregation;
import org.elasticsearch.search.aggregations.AggregationExecutionException;
import org.elasticsearch.search.aggregations.Aggregator;
import org.elasticsearch.search.aggregations.HasAggregations;
import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregation;
import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregator;
import org.elasticsearch.search.aggregations.metrics.InternalNumericMetricsAggregation;
import org.elasticsearch.search.aggregations.metrics.NumericMetricsAggregator;
import java.util.ArrayList;
import java.util.List;
/**
* A path that can be used to sort/order buckets (in some multi-bucket aggregations, e.g. terms & histogram) based on
* sub-aggregations. The path may point to either a single-bucket aggregation or a metrics aggregation. If the path
* points to a single-bucket aggregation, the sort will be applied based on the {@code doc_count} of the bucket. If this
* path points to a metrics aggregation, if it's a single-value metrics (eg. avg, max, min, etc..) the sort will be
* applied on that single value. If it points to a multi-value metrics, the path should point out what metric should be
* the sort-by value.
* <p>
* The path has the following form:
* <center>{@code <aggregation_name>['>'<aggregation_name>*]['.'<metric_name>]}</center>
* <p>
* Examples:
*
* <ul>
* <li>
* {@code agg1>agg2>agg3} - where agg1, agg2 and agg3 are all single-bucket aggs (eg filter, nested, missing, etc..). In
* this case, the order will be based on the number of documents under {@code agg3}.
* </li>
* <li>
* {@code agg1>agg2>agg3} - where agg1 and agg2 are both single-bucket aggs and agg3 is a single-value metrics agg (eg avg, max, min, etc..).
* In this case, the order will be based on the value of {@code agg3}.
* </li>
* <li>
* {@code agg1>agg2>agg3.avg} - where agg1 and agg2 are both single-bucket aggs and agg3 is a multi-value metrics agg (eg stats, extended_stats, etc...).
* In this case, the order will be based on the avg value of {@code agg3}.
* </li>
* </ul>
*
*/
public class AggregationPath {
private static final String AGG_DELIM = ">";
public static AggregationPath parse(String path) {
String[] elements = Strings.tokenizeToStringArray(path, AGG_DELIM);
List<PathElement> tokens = new ArrayList<>(elements.length);
String[] tuple = new String[2];
for (int i = 0; i < elements.length; i++) {
String element = elements[i];
if (i == elements.length - 1) {
int index = element.lastIndexOf('[');
if (index >= 0) {
if (index == 0 || index > element.length() - 3) {
throw new AggregationExecutionException("Invalid path element [" + element + "] in path [" + path + "]");
}
if (element.charAt(element.length() - 1) != ']') {
throw new AggregationExecutionException("Invalid path element [" + element + "] in path [" + path + "]");
}
tokens.add(new PathElement(element, element.substring(0, index), element.substring(index + 1, element.length() - 1)));
continue;
}
index = element.lastIndexOf('.');
if (index < 0) {
tokens.add(new PathElement(element, element, null));
continue;
}
if (index == 0 || index > element.length() - 2) {
throw new AggregationExecutionException("Invalid path element [" + element + "] in path [" + path + "]");
}
tuple = split(element, index, tuple);
tokens.add(new PathElement(element, tuple[0], tuple[1]));
} else {
int index = element.lastIndexOf('[');
if (index >= 0) {
if (index == 0 || index > element.length() - 3) {
throw new AggregationExecutionException("Invalid path element [" + element + "] in path [" + path + "]");
}
if (element.charAt(element.length() - 1) != ']') {
throw new AggregationExecutionException("Invalid path element [" + element + "] in path [" + path + "]");
}
tokens.add(new PathElement(element, element.substring(0, index), element.substring(index + 1, element.length() - 1)));
continue;
}
tokens.add(new PathElement(element, element, null));
}
}
return new AggregationPath(tokens);
}
public static class PathElement {
private final String fullName;
public final String name;
public final String key;
public PathElement(String fullName, String name, String key) {
this.fullName = fullName;
this.name = name;
this.key = key;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
PathElement token = (PathElement) o;
if (key != null ? !key.equals(token.key) : token.key != null) return false;
if (!name.equals(token.name)) return false;
return true;
}
@Override
public int hashCode() {
int result = name.hashCode();
result = 31 * result + (key != null ? key.hashCode() : 0);
return result;
}
@Override
public String toString() {
return fullName;
}
}
private final List<PathElement> pathElements;
public AggregationPath(List<PathElement> tokens) {
this.pathElements = tokens;
if (tokens == null || tokens.size() == 0) {
throw new IllegalArgumentException("Invalid path [" + this + "]");
}
}
@Override
public String toString() {
return Strings.arrayToDelimitedString(pathElements.toArray(), AGG_DELIM);
}
public PathElement lastPathElement() {
return pathElements.get(pathElements.size() - 1);
}
public List<PathElement> getPathElements() {
return this.pathElements;
}
public List<String> getPathElementsAsStringList() {
List<String> stringPathElements = new ArrayList<>();
for (PathElement pathElement : this.pathElements) {
stringPathElements.add(pathElement.name);
if (pathElement.key != null) {
stringPathElements.add(pathElement.key);
}
}
return stringPathElements;
}
public AggregationPath subPath(int offset, int length) {
List<PathElement> subTokens = new ArrayList<>(pathElements.subList(offset, offset + length));
return new AggregationPath(subTokens);
}
/**
* Resolves the value pointed by this path given an aggregations root
*
* @param root The root that serves as a point of reference for this path
* @return The resolved value
*/
public double resolveValue(HasAggregations root) {
HasAggregations parent = root;
double value = Double.NaN;
for (int i = 0; i < pathElements.size(); i++) {
AggregationPath.PathElement token = pathElements.get(i);
Aggregation agg = parent.getAggregations().get(token.name);
if (agg == null) {
throw new IllegalArgumentException("Invalid order path [" + this +
"]. Cannot find aggregation named [" + token.name + "]");
}
if (agg instanceof SingleBucketAggregation) {
if (token.key != null && !token.key.equals("doc_count")) {
throw new IllegalArgumentException("Invalid order path [" + this +
"]. Unknown value key [" + token.key + "] for single-bucket aggregation [" + token.name +
"]. Either use [doc_count] as key or drop the key all together");
}
parent = (SingleBucketAggregation) agg;
value = ((SingleBucketAggregation) agg).getDocCount();
continue;
}
// the agg can only be a metrics agg, and a metrics agg must be at the end of the path
if (i != pathElements.size() - 1) {
throw new IllegalArgumentException("Invalid order path [" + this +
"]. Metrics aggregations cannot have sub-aggregations (at [" + token + ">" + pathElements.get(i + 1) + "]");
}
if (agg instanceof InternalNumericMetricsAggregation.SingleValue) {
if (token.key != null && !token.key.equals("value")) {
throw new IllegalArgumentException("Invalid order path [" + this +
"]. Unknown value key [" + token.key + "] for single-value metric aggregation [" + token.name +
"]. Either use [value] as key or drop the key all together");
}
parent = null;
value = ((InternalNumericMetricsAggregation.SingleValue) agg).value();
continue;
}
// we're left with a multi-value metric agg
if (token.key == null) {
throw new IllegalArgumentException("Invalid order path [" + this +
"]. Missing value key in [" + token + "] which refers to a multi-value metric aggregation");
}
parent = null;
value = ((InternalNumericMetricsAggregation.MultiValue) agg).value(token.key);
}
return value;
}
/**
* Resolves the aggregator pointed by this path using the given root as a point of reference.
*
* @param root The point of reference of this path
* @return The aggregator pointed by this path starting from the given aggregator as a point of reference
*/
public Aggregator resolveAggregator(Aggregator root) {
Aggregator aggregator = root;
for (int i = 0; i < pathElements.size(); i++) {
AggregationPath.PathElement token = pathElements.get(i);
aggregator = aggregator.subAggregator(token.name);
assert (aggregator instanceof SingleBucketAggregator && i <= pathElements.size() - 1)
|| (aggregator instanceof NumericMetricsAggregator && i == pathElements.size() - 1) :
"this should be picked up before aggregation execution - on validate";
}
return aggregator;
}
/**
* Resolves the topmost aggregator pointed by this path using the given root as a point of reference.
*
* @param root The point of reference of this path
* @return The first child aggregator of the root pointed by this path
*/
public Aggregator resolveTopmostAggregator(Aggregator root) {
AggregationPath.PathElement token = pathElements.get(0);
Aggregator aggregator = root.subAggregator(token.name);
assert (aggregator instanceof SingleBucketAggregator )
|| (aggregator instanceof NumericMetricsAggregator) : "this should be picked up before aggregation execution - on validate";
return aggregator;
}
/**
* Validates this path over the given aggregator as a point of reference.
*
* @param root The point of reference of this path
* @throws AggregationExecutionException on validation error
*/
public void validate(Aggregator root) throws AggregationExecutionException {
Aggregator aggregator = root;
for (int i = 0; i < pathElements.size(); i++) {
aggregator = aggregator.subAggregator(pathElements.get(i).name);
if (aggregator == null) {
throw new AggregationExecutionException("Invalid aggregator order path [" + this + "]. Unknown aggregation ["
+ pathElements.get(i).name + "]");
}
if (i < pathElements.size() - 1) {
// we're in the middle of the path, so the aggregator can only be a single-bucket aggregator
if (!(aggregator instanceof SingleBucketAggregator)) {
throw new AggregationExecutionException("Invalid aggregation order path [" + this +
"]. Buckets can only be sorted on a sub-aggregator path " +
"that is built out of zero or more single-bucket aggregations within the path and a final " +
"single-bucket or a metrics aggregation at the path end. Sub-path [" +
subPath(0, i + 1) + "] points to non single-bucket aggregation");
}
if (pathElements.get(i).key != null) {
throw new AggregationExecutionException("Invalid aggregation order path [" + this +
"]. Buckets can only be sorted on a sub-aggregator path " +
"that is built out of zero or more single-bucket aggregations within the path and a " +
"final single-bucket or a metrics aggregation at the path end. Sub-path [" +
subPath(0, i + 1) + "] points to non single-bucket aggregation");
}
}
}
boolean singleBucket = aggregator instanceof SingleBucketAggregator;
if (!singleBucket && !(aggregator instanceof NumericMetricsAggregator)) {
throw new AggregationExecutionException("Invalid aggregation order path [" + this +
"]. Buckets can only be sorted on a sub-aggregator path " +
"that is built out of zero or more single-bucket aggregations within the path and a final " +
"single-bucket or a metrics aggregation at the path end.");
}
AggregationPath.PathElement lastToken = lastPathElement();
if (singleBucket) {
if (lastToken.key != null && !"doc_count".equals(lastToken.key)) {
throw new AggregationExecutionException("Invalid aggregation order path [" + this +
"]. Ordering on a single-bucket aggregation can only be done on its doc_count. " +
"Either drop the key (a la \"" + lastToken.name + "\") or change it to \"doc_count\" (a la \"" + lastToken.name + ".doc_count\")");
}
return; // perfectly valid to sort on single-bucket aggregation (will be sored on its doc_count)
}
if (aggregator instanceof NumericMetricsAggregator.SingleValue) {
if (lastToken.key != null && !"value".equals(lastToken.key)) {
throw new AggregationExecutionException("Invalid aggregation order path [" + this +
"]. Ordering on a single-value metrics aggregation can only be done on its value. " +
"Either drop the key (a la \"" + lastToken.name + "\") or change it to \"value\" (a la \"" + lastToken.name + ".value\")");
}
return; // perfectly valid to sort on single metric aggregation (will be sorted on its associated value)
}
// the aggregator must be of a multi-value metrics type
if (lastToken.key == null) {
throw new AggregationExecutionException("Invalid aggregation order path [" + this +
"]. When ordering on a multi-value metrics aggregation a metric name must be specified");
}
if (!((NumericMetricsAggregator.MultiValue) aggregator).hasMetric(lastToken.key)) {
throw new AggregationExecutionException("Invalid aggregation order path [" + this +
"]. Unknown metric name [" + lastToken.key + "] on multi-value metrics aggregation [" + lastToken.name + "]");
}
}
private static String[] split(String toSplit, int index, String[] result) {
result[0] = toSplit.substring(0, index);
result[1] = toSplit.substring(index + 1);
return result;
}
}