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;
054
055
056
057/** Shows simple usage of dynamic range faceting, using the
058 *  expressions module to calculate distance. */
059public class DistanceFacetsExample implements Closeable {
060
061  final DoubleRange ONE_KM = new DoubleRange("< 1 km", 0.0, true, 1.0, false);
062  final DoubleRange TWO_KM = new DoubleRange("< 2 km", 0.0, true, 2.0, false);
063  final DoubleRange FIVE_KM = new DoubleRange("< 5 km", 0.0, true, 5.0, false);
064  final DoubleRange TEN_KM = new DoubleRange("< 10 km", 0.0, true, 10.0, false);
065
066  private final Directory indexDir = new RAMDirectory();
067  private IndexSearcher searcher;
068  private final FacetsConfig config = new FacetsConfig();
069
070  /** The "home" latitude. */
071  public final static double ORIGIN_LATITUDE = 40.7143528;
072
073  /** The "home" longitude. */
074  public final static double ORIGIN_LONGITUDE = -74.0059731;
075
076  /** Radius of the Earth in KM
077   *
078   * NOTE: this is approximate, because the earth is a bit
079   * wider at the equator than the poles.  See
080   * http://en.wikipedia.org/wiki/Earth_radius */
081  public final static double EARTH_RADIUS_KM = 6371.01;
082
083  /** Empty constructor */
084  public DistanceFacetsExample() {}
085  
086  /** Build the example index. */
087  public void index() throws IOException {
088    IndexWriter writer = new IndexWriter(indexDir, new IndexWriterConfig(FacetExamples.EXAMPLES_VER, 
089        new WhitespaceAnalyzer(FacetExamples.EXAMPLES_VER)));
090
091    // TODO: we could index in radians instead ... saves all the conversions in getBoundingBoxFilter
092
093    // Add documents with latitude/longitude location:
094    Document doc = new Document();
095    doc.add(new DoubleField("latitude", 40.759011, Field.Store.NO));
096    doc.add(new DoubleField("longitude", -73.9844722, Field.Store.NO));
097    writer.addDocument(doc);
098    
099    doc = new Document();
100    doc.add(new DoubleField("latitude", 40.718266, Field.Store.NO));
101    doc.add(new DoubleField("longitude", -74.007819, Field.Store.NO));
102    writer.addDocument(doc);
103    
104    doc = new Document();
105    doc.add(new DoubleField("latitude", 40.7051157, Field.Store.NO));
106    doc.add(new DoubleField("longitude", -74.0088305, Field.Store.NO));
107    writer.addDocument(doc);
108
109    // Open near-real-time searcher
110    searcher = new IndexSearcher(DirectoryReader.open(writer, true));
111    writer.close();
112  }
113
114  private ValueSource getDistanceValueSource() {
115    Expression distance;
116    try {
117      distance = JavascriptCompiler.compile(
118                  "haversin(" + ORIGIN_LATITUDE + "," + ORIGIN_LONGITUDE + ",latitude,longitude)");
119    } catch (ParseException pe) {
120      // Should not happen
121      throw new RuntimeException(pe);
122    }
123    SimpleBindings bindings = new SimpleBindings();
124    bindings.add(new SortField("latitude", SortField.Type.DOUBLE));
125    bindings.add(new SortField("longitude", SortField.Type.DOUBLE));
126
127    return distance.getValueSource(bindings);
128  }
129
130  /** Given a latitude and longitude (in degrees) and the
131   *  maximum great circle (surface of the earth) distance,
132   *  returns a simple Filter bounding box to "fast match"
133   *  candidates. */
134  public static Filter getBoundingBoxFilter(double originLat, double originLng, double maxDistanceKM) {
135
136    // Basic bounding box geo math from
137    // http://JanMatuschek.de/LatitudeLongitudeBoundingCoordinates,
138    // licensed under creative commons 3.0:
139    // http://creativecommons.org/licenses/by/3.0
140
141    // TODO: maybe switch to recursive prefix tree instead
142    // (in lucene/spatial)?  It should be more efficient
143    // since it's a 2D trie...
144
145    // Degrees -> Radians:
146    double originLatRadians = Math.toRadians(originLat);
147    double originLngRadians = Math.toRadians(originLng);
148
149    double angle = maxDistanceKM / EARTH_RADIUS_KM;
150
151    double minLat = originLatRadians - angle;
152    double maxLat = originLatRadians + angle;
153
154    double minLng;
155    double maxLng;
156    if (minLat > Math.toRadians(-90) && maxLat < Math.toRadians(90)) {
157      double delta = Math.asin(Math.sin(angle)/Math.cos(originLatRadians));
158      minLng = originLngRadians - delta;
159      if (minLng < Math.toRadians(-180)) {
160        minLng += 2 * Math.PI;
161      }
162      maxLng = originLngRadians + delta;
163      if (maxLng > Math.toRadians(180)) {
164        maxLng -= 2 * Math.PI;
165      }
166    } else {
167      // The query includes a pole!
168      minLat = Math.max(minLat, Math.toRadians(-90));
169      maxLat = Math.min(maxLat, Math.toRadians(90));
170      minLng = Math.toRadians(-180);
171      maxLng = Math.toRadians(180);
172    }
173
174    BooleanFilter f = new BooleanFilter();
175
176    // Add latitude range filter:
177    f.add(NumericRangeFilter.newDoubleRange("latitude", Math.toDegrees(minLat), Math.toDegrees(maxLat), true, true),
178          BooleanClause.Occur.MUST);
179
180    // Add longitude range filter:
181    if (minLng > maxLng) {
182      // The bounding box crosses the international date
183      // line:
184      BooleanFilter lonF = new BooleanFilter();
185      lonF.add(NumericRangeFilter.newDoubleRange("longitude", Math.toDegrees(minLng), null, true, true),
186               BooleanClause.Occur.SHOULD);
187      lonF.add(NumericRangeFilter.newDoubleRange("longitude", null, Math.toDegrees(maxLng), true, true),
188               BooleanClause.Occur.SHOULD);
189      f.add(lonF, BooleanClause.Occur.MUST);
190    } else {
191      f.add(NumericRangeFilter.newDoubleRange("longitude", Math.toDegrees(minLng), Math.toDegrees(maxLng), true, true),
192            BooleanClause.Occur.MUST);
193    }
194
195    return f;
196  }
197
198  /** User runs a query and counts facets. */
199  public FacetResult search() throws IOException {
200
201    FacetsCollector fc = new FacetsCollector();
202
203    searcher.search(new MatchAllDocsQuery(), fc);
204
205    Facets facets = new DoubleRangeFacetCounts("field", getDistanceValueSource(), fc,
206                                               getBoundingBoxFilter(ORIGIN_LATITUDE, ORIGIN_LONGITUDE, 10.0),
207                                               ONE_KM,
208                                               TWO_KM,
209                                               FIVE_KM,
210                                               TEN_KM);
211
212    return facets.getTopChildren(10, "field");
213  }
214
215  /** User drills down on the specified range. */
216  public TopDocs drillDown(DoubleRange range) throws IOException {
217
218    // Passing no baseQuery means we drill down on all
219    // documents ("browse only"):
220    DrillDownQuery q = new DrillDownQuery(null);
221    final ValueSource vs = getDistanceValueSource();
222    q.add("field", range.getFilter(getBoundingBoxFilter(ORIGIN_LATITUDE, ORIGIN_LONGITUDE, range.max), vs));
223    DrillSideways ds = new DrillSideways(searcher, config, (TaxonomyReader) null) {
224        @Override
225        protected Facets buildFacetsResult(FacetsCollector drillDowns, FacetsCollector[] drillSideways, String[] drillSidewaysDims) throws IOException {        
226          assert drillSideways.length == 1;
227          return new DoubleRangeFacetCounts("field", vs, drillSideways[0], ONE_KM, TWO_KM, FIVE_KM, TEN_KM);
228        }
229      };
230    return ds.search(q, 10).hits;
231  }
232
233  @Override
234  public void close() throws IOException {
235    searcher.getIndexReader().close();
236    indexDir.close();
237  }
238
239  /** Runs the search and drill-down examples and prints the results. */
240  @SuppressWarnings("unchecked")
241  public static void main(String[] args) throws Exception {
242    DistanceFacetsExample example = new DistanceFacetsExample();
243    example.index();
244
245    System.out.println("Distance facet counting example:");
246    System.out.println("-----------------------");
247    System.out.println(example.search());
248
249    System.out.println("\n");
250    System.out.println("Distance facet drill-down example (field/< 2 km):");
251    System.out.println("---------------------------------------------");
252    TopDocs hits = example.drillDown(example.TWO_KM);
253    System.out.println(hits.totalHits + " totalHits");
254
255    example.close();
256  }
257}