package org.apache.lucene.facet.search;
import java.io.IOException;
import java.util.List;
import org.apache.lucene.facet.params.FacetSearchParams;
import org.apache.lucene.facet.sampling.RandomSampler;
import org.apache.lucene.facet.sampling.Sampler;
import org.apache.lucene.facet.sampling.SamplingAccumulator;
import org.apache.lucene.facet.taxonomy.TaxonomyReader;
import org.apache.lucene.index.IndexReader;
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.
*/
/**
* {@link FacetsAccumulator} whose behavior regarding complements, sampling,
* etc. is not set up front but rather is determined at accumulation time
* according to the statistics of the accumulated set of documents and the
* index.
* <p>
* Note: Sampling accumulation (Accumulation over a sampled-set of the results),
* does not guarantee accurate values for
* {@link FacetResult#getNumValidDescendants()}.
*
* @lucene.experimental
*/
public final class AdaptiveFacetsAccumulator extends StandardFacetsAccumulator {
private Sampler sampler = new RandomSampler();
/**
* Create an {@link AdaptiveFacetsAccumulator}
* @see StandardFacetsAccumulator#StandardFacetsAccumulator(FacetSearchParams, IndexReader, TaxonomyReader)
*/
public AdaptiveFacetsAccumulator(FacetSearchParams searchParams, IndexReader indexReader,
TaxonomyReader taxonomyReader) {
super(searchParams, indexReader, taxonomyReader);
}
/**
* Create an {@link AdaptiveFacetsAccumulator}
*
* @see StandardFacetsAccumulator#StandardFacetsAccumulator(FacetSearchParams,
* IndexReader, TaxonomyReader, FacetArrays)
*/
public AdaptiveFacetsAccumulator(FacetSearchParams searchParams, IndexReader indexReader,
TaxonomyReader taxonomyReader, FacetArrays facetArrays) {
super(searchParams, indexReader, taxonomyReader, facetArrays);
}
/**
* Set the sampler.
* @param sampler sampler to set
*/
public void setSampler(Sampler sampler) {
this.sampler = sampler;
}
@Override
public List<FacetResult> accumulate(ScoredDocIDs docids) throws IOException {
StandardFacetsAccumulator delegee = appropriateFacetCountingAccumulator(docids);
if (delegee == this) {
return super.accumulate(docids);
}
return delegee.accumulate(docids);
}
/**
* Compute the appropriate facet accumulator to use.
* If no special/clever adaptation is possible/needed return this (self).
*/
private StandardFacetsAccumulator appropriateFacetCountingAccumulator(ScoredDocIDs docids) {
// Verify that searchPareams permit sampling/complement/etc... otherwise do default
if (!mayComplement()) {
return this;
}
// Now we're sure we can use the sampling methods as we're in a counting only mode
// Verify that sampling is enabled and required ... otherwise do default
if (sampler == null || !sampler.shouldSample(docids)) {
return this;
}
SamplingAccumulator samplingAccumulator = new SamplingAccumulator(sampler, searchParams, indexReader, taxonomyReader);
samplingAccumulator.setComplementThreshold(getComplementThreshold());
return samplingAccumulator;
}
/**
* @return the sampler in effect
*/
public final Sampler getSampler() {
return sampler;
}
}