Source code

001package org.apache.lucene.demo.facet;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one or more
005 * contributor license agreements.  See the NOTICE file distributed with
006 * this work for additional information regarding copyright ownership.
007 * The ASF licenses this file to You under the Apache License, Version 2.0
008 * (the "License"); you may not use this file except in compliance with
009 * the License.  You may obtain a copy of the License at
010 *
011 *     http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 */
019
020import java.io.Closeable;
021import java.io.IOException;
022import java.text.ParseException;
023
024import org.apache.lucene.analysis.core.WhitespaceAnalyzer;
025import org.apache.lucene.document.Document;
026import org.apache.lucene.document.DoubleField;
027import org.apache.lucene.document.Field;
028import org.apache.lucene.expressions.Expression;
029import org.apache.lucene.expressions.SimpleBindings;
030import org.apache.lucene.expressions.js.JavascriptCompiler;
031import org.apache.lucene.facet.DrillDownQuery;
032import org.apache.lucene.facet.DrillSideways;
033import org.apache.lucene.facet.FacetResult;
034import org.apache.lucene.facet.Facets;
035import org.apache.lucene.facet.FacetsCollector;
036import org.apache.lucene.facet.FacetsConfig;
037import org.apache.lucene.facet.range.DoubleRange;
038import org.apache.lucene.facet.range.DoubleRangeFacetCounts;
039import org.apache.lucene.facet.taxonomy.TaxonomyReader;
040import org.apache.lucene.index.DirectoryReader;
041import org.apache.lucene.index.IndexWriter;
042import org.apache.lucene.index.IndexWriterConfig;
043import org.apache.lucene.queries.BooleanFilter;
044import org.apache.lucene.queries.function.ValueSource;
045import org.apache.lucene.search.BooleanClause;
046import org.apache.lucene.search.Filter;
047import org.apache.lucene.search.IndexSearcher;
048import org.apache.lucene.search.MatchAllDocsQuery;
049import org.apache.lucene.search.NumericRangeFilter;
050import org.apache.lucene.search.SortField;
051import org.apache.lucene.search.TopDocs;
052import org.apache.lucene.store.Directory;
053import org.apache.lucene.store.RAMDirectory;
054import org.apache.lucene.util.SloppyMath;
055
056
057
058/** Shows simple usage of dynamic range faceting, using the
059 *  expressions module to calculate distance. */
060public class DistanceFacetsExample implements Closeable {
061
062  final DoubleRange ONE_KM = new DoubleRange("< 1 km", 0.0, true, 1.0, false);
063  final DoubleRange TWO_KM = new DoubleRange("< 2 km", 0.0, true, 2.0, false);
064  final DoubleRange FIVE_KM = new DoubleRange("< 5 km", 0.0, true, 5.0, false);
065  final DoubleRange TEN_KM = new DoubleRange("< 10 km", 0.0, true, 10.0, false);
066
067  private final Directory indexDir = new RAMDirectory();
068  private IndexSearcher searcher;
069  private final FacetsConfig config = new FacetsConfig();
070
071  /** The "home" latitude. */
072  public final static double ORIGIN_LATITUDE = 40.7143528;
073
074  /** The "home" longitude. */
075  public final static double ORIGIN_LONGITUDE = -74.0059731;
076
077  /** Radius of the Earth in KM
078   *
079   * NOTE: this is approximate, because the earth is a bit
080   * wider at the equator than the poles.  See
081   * http://en.wikipedia.org/wiki/Earth_radius */
082  public final static double EARTH_RADIUS_KM = 6371.01;
083
084  /** Empty constructor */
085  public DistanceFacetsExample() {}
086  
087  /** Build the example index. */
088  public void index() throws IOException {
089    IndexWriter writer = new IndexWriter(indexDir, new IndexWriterConfig(FacetExamples.EXAMPLES_VER, 
090        new WhitespaceAnalyzer(FacetExamples.EXAMPLES_VER)));
091
092    // TODO: we could index in radians instead ... saves all the conversions in getBoundingBoxFilter
093
094    // Add documents with latitude/longitude location:
095    Document doc = new Document();
096    doc.add(new DoubleField("latitude", 40.759011, Field.Store.NO));
097    doc.add(new DoubleField("longitude", -73.9844722, Field.Store.NO));
098    writer.addDocument(doc);
099    
100    doc = new Document();
101    doc.add(new DoubleField("latitude", 40.718266, Field.Store.NO));
102    doc.add(new DoubleField("longitude", -74.007819, Field.Store.NO));
103    writer.addDocument(doc);
104    
105    doc = new Document();
106    doc.add(new DoubleField("latitude", 40.7051157, Field.Store.NO));
107    doc.add(new DoubleField("longitude", -74.0088305, Field.Store.NO));
108    writer.addDocument(doc);
109
110    // Open near-real-time searcher
111    searcher = new IndexSearcher(DirectoryReader.open(writer, true));
112    writer.close();
113  }
114
115  private ValueSource getDistanceValueSource() {
116    Expression distance;
117    try {
118      distance = JavascriptCompiler.compile(
119                  "haversin(" + ORIGIN_LATITUDE + "," + ORIGIN_LONGITUDE + ",latitude,longitude)");
120    } catch (ParseException pe) {
121      // Should not happen
122      throw new RuntimeException(pe);
123    }
124    SimpleBindings bindings = new SimpleBindings();
125    bindings.add(new SortField("latitude", SortField.Type.DOUBLE));
126    bindings.add(new SortField("longitude", SortField.Type.DOUBLE));
127
128    return distance.getValueSource(bindings);
129  }
130
131  /** Given a latitude and longitude (in degrees) and the
132   *  maximum great circle (surface of the earth) distance,
133   *  returns a simple Filter bounding box to "fast match"
134   *  candidates. */
135  public static Filter getBoundingBoxFilter(double originLat, double originLng, double maxDistanceKM) {
136
137    // Basic bounding box geo math from
138    // http://JanMatuschek.de/LatitudeLongitudeBoundingCoordinates,
139    // licensed under creative commons 3.0:
140    // http://creativecommons.org/licenses/by/3.0
141
142    // TODO: maybe switch to recursive prefix tree instead
143    // (in lucene/spatial)?  It should be more efficient
144    // since it's a 2D trie...
145
146    // Degrees -> Radians:
147    double originLatRadians = Math.toRadians(originLat);
148    double originLngRadians = Math.toRadians(originLng);
149
150    double angle = maxDistanceKM / (SloppyMath.earthDiameter(originLat) / 2.0);
151
152    double minLat = originLatRadians - angle;
153    double maxLat = originLatRadians + angle;
154
155    double minLng;
156    double maxLng;
157    if (minLat > Math.toRadians(-90) && maxLat < Math.toRadians(90)) {
158      double delta = Math.asin(Math.sin(angle)/Math.cos(originLatRadians));
159      minLng = originLngRadians - delta;
160      if (minLng < Math.toRadians(-180)) {
161        minLng += 2 * Math.PI;
162      }
163      maxLng = originLngRadians + delta;
164      if (maxLng > Math.toRadians(180)) {
165        maxLng -= 2 * Math.PI;
166      }
167    } else {
168      // The query includes a pole!
169      minLat = Math.max(minLat, Math.toRadians(-90));
170      maxLat = Math.min(maxLat, Math.toRadians(90));
171      minLng = Math.toRadians(-180);
172      maxLng = Math.toRadians(180);
173    }
174
175    BooleanFilter f = new BooleanFilter();
176
177    // Add latitude range filter:
178    f.add(NumericRangeFilter.newDoubleRange("latitude", Math.toDegrees(minLat), Math.toDegrees(maxLat), true, true),
179          BooleanClause.Occur.MUST);
180
181    // Add longitude range filter:
182    if (minLng > maxLng) {
183      // The bounding box crosses the international date
184      // line:
185      BooleanFilter lonF = new BooleanFilter();
186      lonF.add(NumericRangeFilter.newDoubleRange("longitude", Math.toDegrees(minLng), null, true, true),
187               BooleanClause.Occur.SHOULD);
188      lonF.add(NumericRangeFilter.newDoubleRange("longitude", null, Math.toDegrees(maxLng), true, true),
189               BooleanClause.Occur.SHOULD);
190      f.add(lonF, BooleanClause.Occur.MUST);
191    } else {
192      f.add(NumericRangeFilter.newDoubleRange("longitude", Math.toDegrees(minLng), Math.toDegrees(maxLng), true, true),
193            BooleanClause.Occur.MUST);
194    }
195
196    return f;
197  }
198
199  /** User runs a query and counts facets. */
200  public FacetResult search() throws IOException {
201
202    FacetsCollector fc = new FacetsCollector();
203
204    searcher.search(new MatchAllDocsQuery(), fc);
205
206    Facets facets = new DoubleRangeFacetCounts("field", getDistanceValueSource(), fc,
207                                               getBoundingBoxFilter(ORIGIN_LATITUDE, ORIGIN_LONGITUDE, 10.0),
208                                               ONE_KM,
209                                               TWO_KM,
210                                               FIVE_KM,
211                                               TEN_KM);
212
213    return facets.getTopChildren(10, "field");
214  }
215
216  /** User drills down on the specified range. */
217  public TopDocs drillDown(DoubleRange range) throws IOException {
218
219    // Passing no baseQuery means we drill down on all
220    // documents ("browse only"):
221    DrillDownQuery q = new DrillDownQuery(null);
222    final ValueSource vs = getDistanceValueSource();
223    q.add("field", range.getFilter(getBoundingBoxFilter(ORIGIN_LATITUDE, ORIGIN_LONGITUDE, range.max), vs));
224    DrillSideways ds = new DrillSideways(searcher, config, (TaxonomyReader) null) {
225        @Override
226        protected Facets buildFacetsResult(FacetsCollector drillDowns, FacetsCollector[] drillSideways, String[] drillSidewaysDims) throws IOException {        
227          assert drillSideways.length == 1;
228          return new DoubleRangeFacetCounts("field", vs, drillSideways[0], ONE_KM, TWO_KM, FIVE_KM, TEN_KM);
229        }
230      };
231    return ds.search(q, 10).hits;
232  }
233
234  @Override
235  public void close() throws IOException {
236    searcher.getIndexReader().close();
237    indexDir.close();
238  }
239
240  /** Runs the search and drill-down examples and prints the results. */
241  @SuppressWarnings("unchecked")
242  public static void main(String[] args) throws Exception {
243    DistanceFacetsExample example = new DistanceFacetsExample();
244    example.index();
245
246    System.out.println("Distance facet counting example:");
247    System.out.println("-----------------------");
248    System.out.println(example.search());
249
250    System.out.println("\n");
251    System.out.println("Distance facet drill-down example (field/< 2 km):");
252    System.out.println("---------------------------------------------");
253    TopDocs hits = example.drillDown(example.TWO_KM);
254    System.out.println(hits.totalHits + " totalHits");
255
256    example.close();
257  }
258}