Module org.elasticsearch.server

Package org.elasticsearch.search.aggregations.bucket.nested

Class ReverseNestedAggregator

java.lang.Object

org.elasticsearch.search.aggregations.BucketCollector

org.elasticsearch.search.aggregations.Aggregator

org.elasticsearch.search.aggregations.AggregatorBase

org.elasticsearch.search.aggregations.bucket.BucketsAggregator

org.elasticsearch.search.aggregations.bucket.nested.ReverseNestedAggregator

All Implemented Interfaces:

Closeable, AutoCloseable, Releasable, SingleBucketAggregator

public class ReverseNestedAggregator
extends BucketsAggregator
implements SingleBucketAggregator

Nested Class Summary

Nested classes/interfaces inherited from class org.elasticsearch.search.aggregations.bucket.BucketsAggregator

BucketsAggregator.BucketBuilderForFixedCount<B>, BucketsAggregator.BucketBuilderForVariable<B>, BucketsAggregator.ResultBuilderForVariable<B>, BucketsAggregator.SingleBucketResultBuilder

Nested classes/interfaces inherited from class org.elasticsearch.search.aggregations.Aggregator

Aggregator.BucketComparator, Aggregator.Parser, Aggregator.SubAggCollectionMode

Nested classes/interfaces inherited from class org.elasticsearch.search.aggregations.BucketCollector

BucketCollector.BucketCollectorWrapper

Field Summary

Fields inherited from class org.elasticsearch.search.aggregations.bucket.BucketsAggregator

docCountProvider

Fields inherited from class org.elasticsearch.search.aggregations.AggregatorBase

collectableSubAggregators, DEFAULT_WEIGHT, name, parent, subAggregators

Fields inherited from class org.elasticsearch.search.aggregations.BucketCollector

NO_OP_BUCKET_COLLECTOR, NO_OP_COLLECTOR

Constructor Summary

Constructors

Constructor	Description
ReverseNestedAggregator(String name, AggregatorFactories factories, NestedObjectMapper objectMapper, AggregationContext context, Aggregator parent, CardinalityUpperBound cardinality, Map<String,Object> metadata)

Method Summary

Modifier and Type	Method	Description
InternalAggregation[]	buildAggregations(long[] owningBucketOrds)	Build the results of this aggregation.
InternalAggregation	buildEmptyAggregation()	Build an empty aggregation.
protected LeafBucketCollector	getLeafCollector(AggregationExecutionContext aggCtx, LeafBucketCollector sub)	Collect results for this leaf.

Methods inherited from class org.elasticsearch.search.aggregations.bucket.BucketsAggregator

bucketComparator, bucketDocCount, buildAggregationsForFixedBucketCount, buildAggregationsForSingleBucket, buildAggregationsForVariableBuckets, buildSubAggsForAllBuckets, buildSubAggsForBuckets, close, collectBucket, collectExistingBucket, descendsFromGlobalAggregator, getDocCounts, grow, incrementBucketDocCount, maxBucketOrd, preGetSubLeafCollectors, prepareSubAggs, resolveSortPath, rewriteBuckets

Methods inherited from class org.elasticsearch.search.aggregations.AggregatorBase

addRequestCircuitBreakerBytes, bigArrays, buildEmptySubAggregations, doClose, doPostCollection, doPreCollection, getLeafCollector, metadata, name, parent, pointReaderIfAvailable, postCollection, preCollection, releaseAggregations, scoreMode, searcher, subAggregator, subAggregators, topLevelQuery, toString

Methods inherited from class org.elasticsearch.search.aggregations.Aggregator

buildTopLevel, collectDebugInfo, resolveSortPathOnValidAgg

Methods inherited from class org.elasticsearch.search.aggregations.BucketCollector

asCollector

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

ReverseNestedAggregator

public ReverseNestedAggregator(String name,
 AggregatorFactories factories,
 NestedObjectMapper objectMapper,
 AggregationContext context,
 Aggregator parent,
 CardinalityUpperBound cardinality,
 Map<String,Object> metadata)
                        throws IOException

Throws:

IOException

Method Details

getLeafCollector

protected LeafBucketCollector getLeafCollector(AggregationExecutionContext aggCtx,
 LeafBucketCollector sub)
                                        throws IOException

Description copied from class: AggregatorBase

Collect results for this leaf.

Most Aggregators will return a custom LeafBucketCollector that collects document information for every hit. Callers of this method will make sure to call collect for every hit. So any Aggregator that returns a customer LeafBucketCollector from this method runs at best O(hits) time. See the sum Aggregator for a fairly strait forward example of this.

Some Aggregators are able to correctly collect results on their own, without being iterated by the top level query or the rest of the aggregations framework. These aggregations collect what they need by calling methods on LeafReaderContext and then they return LeafBucketCollector.NO_OP_COLLECTOR to signal that they've done their own collection. These aggregations can do better than O(hits). See the min Aggregator for an example of an aggregation that does this. It happens to run in constant time in some cases.

In other cases MinAggregator can't get correct results by taking the constant time path so instead it returns a custom LeafBucketCollector. This is fairly common for aggregations that have these fast paths because most of these fast paths are only possible when the aggregation is at the root of the tree.

Its also useful to look at the filters Aggregator chooses whether or not it can use the fast path before building the Aggregator rather than on each leaf. Either is fine.

Specified by:

getLeafCollector in class AggregatorBase

Throws:

IOException

buildAggregations

public InternalAggregation[] buildAggregations(long[] owningBucketOrds)
                                        throws IOException

Description copied from class: Aggregator

Build the results of this aggregation.

Specified by:

buildAggregations in class Aggregator

Parameters:

owningBucketOrds - the ordinals of the buckets that we want to collect from this aggregation

Returns:

the results for each ordinal, in the same order as the array of ordinals

Throws:

IOException

buildEmptyAggregation

public InternalAggregation buildEmptyAggregation()

Description copied from class: Aggregator

Build an empty aggregation.

Specified by:

buildEmptyAggregation in class Aggregator