package org.apache.lucene.demo.facet;
import java.io.IOException;
import java.text.ParseException;
import java.util.Collections;
import java.util.List;
import org.apache.lucene.analysis.core.WhitespaceAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field.Store;
import org.apache.lucene.document.NumericDocValuesField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.expressions.Expression;
import org.apache.lucene.expressions.SimpleBindings;
import org.apache.lucene.expressions.js.JavascriptCompiler;
import org.apache.lucene.facet.index.FacetFields;
import org.apache.lucene.facet.params.FacetSearchParams;
import org.apache.lucene.facet.search.FacetResult;
import org.apache.lucene.facet.search.FacetsCollector;
import org.apache.lucene.facet.search.SumValueSourceFacetRequest;
import org.apache.lucene.facet.taxonomy.CategoryPath;
import org.apache.lucene.facet.taxonomy.TaxonomyReader;
import org.apache.lucene.facet.taxonomy.directory.DirectoryTaxonomyReader;
import org.apache.lucene.facet.taxonomy.directory.DirectoryTaxonomyWriter;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.MatchAllDocsQuery;
import org.apache.lucene.search.SortField;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.RAMDirectory;
/*
* 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.
*/
/** Shows facets aggregation by an expression. */
public class ExpressionAggregationFacetsExample {
private final Directory indexDir = new RAMDirectory();
private final Directory taxoDir = new RAMDirectory();
/** Empty constructor */
public ExpressionAggregationFacetsExample() {}
private void add(IndexWriter indexWriter, FacetFields facetFields, String text, String category, long popularity) throws IOException {
Document doc = new Document();
doc.add(new TextField("c", text, Store.NO));
doc.add(new NumericDocValuesField("popularity", popularity));
facetFields.addFields(doc, Collections.singletonList(new CategoryPath(category, '/')));
indexWriter.addDocument(doc);
}
/** Build the example index. */
private void index() throws IOException {
IndexWriter indexWriter = new IndexWriter(indexDir, new IndexWriterConfig(FacetExamples.EXAMPLES_VER,
new WhitespaceAnalyzer(FacetExamples.EXAMPLES_VER)));
// Writes facet ords to a separate directory from the main index
DirectoryTaxonomyWriter taxoWriter = new DirectoryTaxonomyWriter(taxoDir);
// Reused across documents, to add the necessary facet fields
FacetFields facetFields = new FacetFields(taxoWriter);
add(indexWriter, facetFields, "foo bar", "A/B", 5L);
add(indexWriter, facetFields, "foo foo bar", "A/C", 3L);
indexWriter.close();
taxoWriter.close();
}
/** User runs a query and aggregates facets. */
private List<FacetResult> search() throws IOException, ParseException {
DirectoryReader indexReader = DirectoryReader.open(indexDir);
IndexSearcher searcher = new IndexSearcher(indexReader);
TaxonomyReader taxoReader = new DirectoryTaxonomyReader(taxoDir);
// Aggregate categories by an expression that combines the document's score
// and its popularity field
Expression expr = JavascriptCompiler.compile("_score * sqrt(popularity)");
SimpleBindings bindings = new SimpleBindings();
bindings.add(new SortField("_score", SortField.Type.SCORE)); // the score of the document
bindings.add(new SortField("popularity", SortField.Type.LONG)); // the value of the 'popularity' field
FacetSearchParams fsp = new FacetSearchParams(
new SumValueSourceFacetRequest(new CategoryPath("A"), 10, expr.getValueSource(bindings), true));
// Aggregates the facet values
FacetsCollector fc = FacetsCollector.create(fsp, searcher.getIndexReader(), taxoReader);
// MatchAllDocsQuery is for "browsing" (counts facets
// for all non-deleted docs in the index); normally
// you'd use a "normal" query, and use MultiCollector to
// wrap collecting the "normal" hits and also facets:
searcher.search(new MatchAllDocsQuery(), fc);
// Retrieve results
List<FacetResult> facetResults = fc.getFacetResults();
indexReader.close();
taxoReader.close();
return facetResults;
}
/** Runs the search example. */
public List<FacetResult> runSearch() throws IOException, ParseException {
index();
return search();
}
/** Runs the search and drill-down examples and prints the results. */
public static void main(String[] args) throws Exception {
System.out.println("Facet counting example:");
System.out.println("-----------------------");
List<FacetResult> results = new ExpressionAggregationFacetsExample().runSearch();
for (FacetResult res : results) {
System.out.println(res);
}
}
}