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