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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.bucket.nested;
import org.apache.lucene.index.IndexReaderContext;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.index.ReaderUtil;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.Weight;
import org.apache.lucene.search.join.BitSetProducer;
import org.apache.lucene.util.BitSet;
import org.elasticsearch.common.lucene.search.Queries;
import org.elasticsearch.index.mapper.object.ObjectMapper;
import org.elasticsearch.search.aggregations.AggregationExecutionException;
import org.elasticsearch.search.aggregations.Aggregator;
import org.elasticsearch.search.aggregations.AggregatorFactories;
import org.elasticsearch.search.aggregations.AggregatorFactory;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.LeafBucketCollector;
import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
import org.elasticsearch.search.aggregations.NonCollectingAggregator;
import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregator;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
import org.elasticsearch.search.aggregations.support.AggregationContext;
import java.io.IOException;
import java.util.List;
import java.util.Map;
/**
*
*/
public class NestedAggregator extends SingleBucketAggregator {
private BitSetProducer parentFilter;
private final Query childFilter;
private DocIdSetIterator childDocs;
private BitSet parentDocs;
public NestedAggregator(String name, AggregatorFactories factories, ObjectMapper objectMapper, AggregationContext aggregationContext, Aggregator parentAggregator, List pipelineAggregators, Map metaData) throws IOException {
super(name, factories, aggregationContext, parentAggregator, pipelineAggregators, metaData);
childFilter = objectMapper.nestedTypeFilter();
}
@Override
public LeafBucketCollector getLeafCollector(final LeafReaderContext ctx, final LeafBucketCollector sub) throws IOException {
// Reset parentFilter, so we resolve the parentDocs for each new segment being searched
this.parentFilter = null;
final IndexReaderContext topLevelContext = ReaderUtil.getTopLevelContext(ctx);
final IndexSearcher searcher = new IndexSearcher(topLevelContext);
searcher.setQueryCache(null);
final Weight weight = searcher.createNormalizedWeight(childFilter, false);
Scorer childDocsScorer = weight.scorer(ctx);
if (childDocsScorer == null) {
childDocs = null;
} else {
childDocs = childDocsScorer.iterator();
}
return new LeafBucketCollectorBase(sub, null) {
@Override
public void collect(int parentDoc, long bucket) throws IOException {
// here we translate the parent doc to a list of its nested docs, and then call super.collect for evey one of them so they'll be collected
// if parentDoc is 0 then this means that this parent doesn't have child docs (b/c these appear always before the parent doc), so we can skip:
if (parentDoc == 0 || childDocs == null) {
return;
}
if (parentFilter == null) {
// The aggs are instantiated in reverse, first the most inner nested aggs and lastly the top level aggs
// So at the time a nested 'nested' aggs is parsed its closest parent nested aggs hasn't been constructed.
// So the trick is to set at the last moment just before needed and we can use its child filter as the
// parent filter.
// Additional NOTE: Before this logic was performed in the setNextReader(...) method, but the the assumption
// that aggs instances are constructed in reverse doesn't hold when buckets are constructed lazily during
// aggs execution
Query parentFilterNotCached = findClosestNestedPath(parent());
if (parentFilterNotCached == null) {
parentFilterNotCached = Queries.newNonNestedFilter();
}
parentFilter = context.searchContext().bitsetFilterCache().getBitSetProducer(parentFilterNotCached);
parentDocs = parentFilter.getBitSet(ctx);
if (parentDocs == null) {
// There are no parentDocs in the segment, so return and set childDocs to null, so we exit early for future invocations.
childDocs = null;
return;
}
}
final int prevParentDoc = parentDocs.prevSetBit(parentDoc - 1);
int childDocId = childDocs.docID();
if (childDocId <= prevParentDoc) {
childDocId = childDocs.advance(prevParentDoc + 1);
}
for (; childDocId < parentDoc; childDocId = childDocs.nextDoc()) {
collectBucket(sub, childDocId, bucket);
}
}
};
}
@Override
public InternalAggregation buildAggregation(long owningBucketOrdinal) throws IOException {
return new InternalNested(name, bucketDocCount(owningBucketOrdinal), bucketAggregations(owningBucketOrdinal), pipelineAggregators(),
metaData());
}
@Override
public InternalAggregation buildEmptyAggregation() {
return new InternalNested(name, 0, buildEmptySubAggregations(), pipelineAggregators(), metaData());
}
private static Query findClosestNestedPath(Aggregator parent) {
for (; parent != null; parent = parent.parent()) {
if (parent instanceof NestedAggregator) {
return ((NestedAggregator) parent).childFilter;
} else if (parent instanceof ReverseNestedAggregator) {
return ((ReverseNestedAggregator) parent).getParentFilter();
}
}
return null;
}
public static class Factory extends AggregatorFactory {
private final String path;
public Factory(String name, String path) {
super(name, InternalNested.TYPE.name());
this.path = path;
}
@Override
public Aggregator createInternal(AggregationContext context, Aggregator parent, boolean collectsFromSingleBucket,
List pipelineAggregators, Map metaData) throws IOException {
if (collectsFromSingleBucket == false) {
return asMultiBucketAggregator(this, context, parent);
}
ObjectMapper objectMapper = context.searchContext().getObjectMapper(path);
if (objectMapper == null) {
return new Unmapped(name, context, parent, pipelineAggregators, metaData);
}
if (!objectMapper.nested().isNested()) {
throw new AggregationExecutionException("[nested] nested path [" + path + "] is not nested");
}
return new NestedAggregator(name, factories, objectMapper, context, parent, pipelineAggregators, metaData);
}
private final static class Unmapped extends NonCollectingAggregator {
public Unmapped(String name, AggregationContext context, Aggregator parent, List pipelineAggregators, Map metaData)
throws IOException {
super(name, context, parent, pipelineAggregators, metaData);
}
@Override
public InternalAggregation buildEmptyAggregation() {
return new InternalNested(name, 0, buildEmptySubAggregations(), pipelineAggregators(), metaData());
}
}
}
}