    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *     http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.lucene.demo.facet;
    018
    019import java.io.IOException;
    020import java.text.ParseException;
    021import org.apache.lucene.analysis.core.WhitespaceAnalyzer;
    022import org.apache.lucene.document.Document;
    023import org.apache.lucene.document.Field.Store;
    024import org.apache.lucene.document.NumericDocValuesField;
    025import org.apache.lucene.document.TextField;
    026import org.apache.lucene.expressions.Expression;
    027import org.apache.lucene.expressions.SimpleBindings;
    028import org.apache.lucene.expressions.js.JavascriptCompiler;
    029import org.apache.lucene.facet.FacetField;
    030import org.apache.lucene.facet.FacetResult;
    031import org.apache.lucene.facet.Facets;
    032import org.apache.lucene.facet.FacetsCollector;
    033import org.apache.lucene.facet.FacetsConfig;
    034import org.apache.lucene.facet.taxonomy.AssociationAggregationFunction;
    035import org.apache.lucene.facet.taxonomy.TaxonomyFacetFloatAssociations;
    036import org.apache.lucene.facet.taxonomy.TaxonomyReader;
    037import org.apache.lucene.facet.taxonomy.directory.DirectoryTaxonomyReader;
    038import org.apache.lucene.facet.taxonomy.directory.DirectoryTaxonomyWriter;
    039import org.apache.lucene.index.DirectoryReader;
    040import org.apache.lucene.index.IndexWriter;
    041import org.apache.lucene.index.IndexWriterConfig;
    042import org.apache.lucene.index.IndexWriterConfig.OpenMode;
    043import org.apache.lucene.search.DoubleValuesSource;
    044import org.apache.lucene.search.IndexSearcher;
    045import org.apache.lucene.search.MatchAllDocsQuery;
    046import org.apache.lucene.store.ByteBuffersDirectory;
    047import org.apache.lucene.store.Directory;
    048
    049/** Shows facets aggregation by an expression. */
    050public class ExpressionAggregationFacetsExample {
    051
    052  private final Directory indexDir = new ByteBuffersDirectory();
    053  private final Directory taxoDir = new ByteBuffersDirectory();
    054  private final FacetsConfig config = new FacetsConfig();
    055
    056  /** Empty constructor */
    057  public ExpressionAggregationFacetsExample() {}
    058
    059  /** Build the example index. */
    060  private void index() throws IOException {
    061    IndexWriter indexWriter =
    062        new IndexWriter(
    063            indexDir, new IndexWriterConfig(new WhitespaceAnalyzer()).setOpenMode(OpenMode.CREATE));
    064
    065    // Writes facet ords to a separate directory from the main index
    066    DirectoryTaxonomyWriter taxoWriter = new DirectoryTaxonomyWriter(taxoDir);
    067
    068    Document doc = new Document();
    069    doc.add(new TextField("c", "foo bar", Store.NO));
    070    doc.add(new NumericDocValuesField("popularity", 5L));
    071    doc.add(new FacetField("A", "B"));
    072    indexWriter.addDocument(config.build(taxoWriter, doc));
    073
    074    doc = new Document();
    075    doc.add(new TextField("c", "foo foo bar", Store.NO));
    076    doc.add(new NumericDocValuesField("popularity", 3L));
    077    doc.add(new FacetField("A", "C"));
    078    indexWriter.addDocument(config.build(taxoWriter, doc));
    079
    080    indexWriter.close();
    081    taxoWriter.close();
    082  }
    083
    084  /** User runs a query and aggregates facets. */
    085  private FacetResult search() throws IOException, ParseException {
    086    DirectoryReader indexReader = DirectoryReader.open(indexDir);
    087    IndexSearcher searcher = new IndexSearcher(indexReader);
    088    TaxonomyReader taxoReader = new DirectoryTaxonomyReader(taxoDir);
    089
    090    // Aggregate categories by an expression that combines the document's score
    091    // and its popularity field
    092    Expression expr = JavascriptCompiler.compile("_score * sqrt(popularity)");
    093    SimpleBindings bindings = new SimpleBindings();
    094    bindings.add("_score", DoubleValuesSource.SCORES); // the score of the document
    095    bindings.add(
    096        "popularity",
    097        DoubleValuesSource.fromLongField("popularity")); // the value of the 'popularity' field
    098
    099    // Aggregates the facet values
    100    FacetsCollector fc = new FacetsCollector(true);
    101
    102    // MatchAllDocsQuery is for "browsing" (counts facets
    103    // for all non-deleted docs in the index); normally
    104    // you'd use a "normal" query:
    105    FacetsCollector.search(searcher, new MatchAllDocsQuery(), 10, fc);
    106
    107    // Retrieve results
    108    Facets facets =
    109        new TaxonomyFacetFloatAssociations(
    110            taxoReader,
    111            config,
    112            fc,
    113            AssociationAggregationFunction.SUM,
    114            expr.getDoubleValuesSource(bindings));
    115    FacetResult result = facets.getTopChildren(10, "A");
    116
    117    indexReader.close();
    118    taxoReader.close();
    119
    120    return result;
    121  }
    122
    123  /** Runs the search example. */
    124  public FacetResult runSearch() throws IOException, ParseException {
    125    index();
    126    return search();
    127  }
    128
    129  /** Runs the search and drill-down examples and prints the results. */
    130  public static void main(String[] args) throws Exception {
    131    System.out.println("Facet counting example:");
    132    System.out.println("-----------------------");
    133    FacetResult result = new ExpressionAggregationFacetsExample().runSearch();
    134    System.out.println(result);
    135  }
    136}