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