Package org.elasticsearch.search.aggregations

Class NonCollectingAggregator

java.lang.Object

org.elasticsearch.search.aggregations.BucketCollector

org.elasticsearch.search.aggregations.Aggregator

org.elasticsearch.search.aggregations.AggregatorBase

org.elasticsearch.search.aggregations.NonCollectingAggregator

All Implemented Interfaces:

Closeable, AutoCloseable, org.apache.lucene.search.Collector, org.elasticsearch.core.Releasable

Direct Known Subclasses:

RangeAggregator.Unmapped

public abstract class NonCollectingAggregator
extends AggregatorBase

An aggregator that is not collected, this can typically be used when running an aggregation over a field that doesn't have a mapping.

Nested Class Summary

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

Aggregator.BucketComparator, Aggregator.Parser, Aggregator.SubAggCollectionMode

Field Summary

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_COLLECTOR

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	NonCollectingAggregator(String name, AggregationContext context, Aggregator parent, AggregatorFactories subFactories, Map<String,Object> metadata)	Build a NonCollectingAggregator for any aggregator.

Method Summary

Modifier and Type	Method	Description
InternalAggregation[]	buildAggregations(long[] owningBucketOrds)	Build the results of this aggregation.
LeafBucketCollector	getLeafCollector(org.apache.lucene.index.LeafReaderContext reader, LeafBucketCollector sub)	Collect results for this leaf.

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

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

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

bucketComparator, buildEmptyAggregation, buildTopLevel, collectDebugInfo, resolveSortPath, resolveSortPathOnValidAgg

Methods inherited from class java.lang.Object

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

Constructor Details

NonCollectingAggregator

protected NonCollectingAggregator(String name,
 AggregationContext context,
 Aggregator parent,
 AggregatorFactories subFactories,
 Map<String,Object> metadata)
                           throws IOException

Build a NonCollectingAggregator for any aggregator.

Throws:

IOException

Method Details

getLeafCollector

public final LeafBucketCollector getLeafCollector(org.apache.lucene.index.LeafReaderContext reader,
 LeafBucketCollector sub)

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

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