Java tutorial
package com.zghw.lucene.demo; /* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.io.Closeable; import java.io.IOException; import java.text.ParseException; import org.apache.lucene.analysis.core.WhitespaceAnalyzer; import org.apache.lucene.document.Document; import org.apache.lucene.document.DoubleField; import org.apache.lucene.document.Field; import org.apache.lucene.expressions.Expression; import org.apache.lucene.expressions.SimpleBindings; import org.apache.lucene.expressions.js.JavascriptCompiler; import org.apache.lucene.facet.DrillDownQuery; import org.apache.lucene.facet.DrillSideways; import org.apache.lucene.facet.FacetResult; import org.apache.lucene.facet.Facets; import org.apache.lucene.facet.FacetsCollector; import org.apache.lucene.facet.FacetsConfig; import org.apache.lucene.facet.range.DoubleRange; import org.apache.lucene.facet.range.DoubleRangeFacetCounts; import org.apache.lucene.facet.taxonomy.TaxonomyReader; import org.apache.lucene.index.DirectoryReader; import org.apache.lucene.index.IndexWriter; import org.apache.lucene.index.IndexWriterConfig; import org.apache.lucene.queries.BooleanFilter; import org.apache.lucene.queries.function.ValueSource; import org.apache.lucene.search.BooleanClause; import org.apache.lucene.search.Filter; import org.apache.lucene.search.IndexSearcher; import org.apache.lucene.search.MatchAllDocsQuery; import org.apache.lucene.search.NumericRangeFilter; import org.apache.lucene.search.SortField; import org.apache.lucene.search.TopDocs; import org.apache.lucene.store.Directory; import org.apache.lucene.store.RAMDirectory; import org.apache.lucene.util.SloppyMath; /** Shows simple usage of dynamic range faceting, using the * expressions module to calculate distance. */ public class DistanceFacetsExample implements Closeable { final DoubleRange ONE_KM = new DoubleRange("< 1 km", 0.0, true, 1.0, false); final DoubleRange TWO_KM = new DoubleRange("< 2 km", 0.0, true, 2.0, false); final DoubleRange FIVE_KM = new DoubleRange("< 5 km", 0.0, true, 5.0, false); final DoubleRange TEN_KM = new DoubleRange("< 10 km", 0.0, true, 10.0, false); private final Directory indexDir = new RAMDirectory(); private IndexSearcher searcher; private final FacetsConfig config = new FacetsConfig(); /** The "home" latitude. */ public final static double ORIGIN_LATITUDE = 40.7143528; /** The "home" longitude. */ public final static double ORIGIN_LONGITUDE = -74.0059731; /** Radius of the Earth in KM * * NOTE: this is approximate, because the earth is a bit * wider at the equator than the poles. See * http://en.wikipedia.org/wiki/Earth_radius */ public final static double EARTH_RADIUS_KM = 6371.01; /** Empty constructor */ public DistanceFacetsExample() { } /** Build the example index. */ public void index() throws IOException { IndexWriter writer = new IndexWriter(indexDir, new IndexWriterConfig(FacetExamples.EXAMPLES_VER, new WhitespaceAnalyzer())); // TODO: we could index in radians instead ... saves all the conversions in getBoundingBoxFilter // Add documents with latitude/longitude location: Document doc = new Document(); doc.add(new DoubleField("latitude", 40.759011, Field.Store.NO)); doc.add(new DoubleField("longitude", -73.9844722, Field.Store.NO)); writer.addDocument(doc); doc = new Document(); doc.add(new DoubleField("latitude", 40.718266, Field.Store.NO)); doc.add(new DoubleField("longitude", -74.007819, Field.Store.NO)); writer.addDocument(doc); doc = new Document(); doc.add(new DoubleField("latitude", 40.7051157, Field.Store.NO)); doc.add(new DoubleField("longitude", -74.0088305, Field.Store.NO)); writer.addDocument(doc); // Open near-real-time searcher searcher = new IndexSearcher(DirectoryReader.open(writer, true)); writer.close(); } private ValueSource getDistanceValueSource() { Expression distance; try { distance = JavascriptCompiler .compile("haversin(" + ORIGIN_LATITUDE + "," + ORIGIN_LONGITUDE + ",latitude,longitude)"); } catch (ParseException pe) { // Should not happen throw new RuntimeException(pe); } SimpleBindings bindings = new SimpleBindings(); bindings.add(new SortField("latitude", SortField.Type.DOUBLE)); bindings.add(new SortField("longitude", SortField.Type.DOUBLE)); return distance.getValueSource(bindings); } /** Given a latitude and longitude (in degrees) and the * maximum great circle (surface of the earth) distance, * returns a simple Filter bounding box to "fast match" * candidates. */ public static Filter getBoundingBoxFilter(double originLat, double originLng, double maxDistanceKM) { // Basic bounding box geo math from // http://JanMatuschek.de/LatitudeLongitudeBoundingCoordinates, // licensed under creative commons 3.0: // http://creativecommons.org/licenses/by/3.0 // TODO: maybe switch to recursive prefix tree instead // (in lucene/spatial)? It should be more efficient // since it's a 2D trie... // Degrees -> Radians: double originLatRadians = Math.toRadians(originLat); double originLngRadians = Math.toRadians(originLng); double angle = maxDistanceKM / (SloppyMath.earthDiameter(originLat) / 2.0); double minLat = originLatRadians - angle; double maxLat = originLatRadians + angle; double minLng; double maxLng; if (minLat > Math.toRadians(-90) && maxLat < Math.toRadians(90)) { double delta = Math.asin(Math.sin(angle) / Math.cos(originLatRadians)); minLng = originLngRadians - delta; if (minLng < Math.toRadians(-180)) { minLng += 2 * Math.PI; } maxLng = originLngRadians + delta; if (maxLng > Math.toRadians(180)) { maxLng -= 2 * Math.PI; } } else { // The query includes a pole! minLat = Math.max(minLat, Math.toRadians(-90)); maxLat = Math.min(maxLat, Math.toRadians(90)); minLng = Math.toRadians(-180); maxLng = Math.toRadians(180); } BooleanFilter f = new BooleanFilter(); // Add latitude range filter: f.add(NumericRangeFilter.newDoubleRange("latitude", Math.toDegrees(minLat), Math.toDegrees(maxLat), true, true), BooleanClause.Occur.MUST); // Add longitude range filter: if (minLng > maxLng) { // The bounding box crosses the international date // line: BooleanFilter lonF = new BooleanFilter(); lonF.add(NumericRangeFilter.newDoubleRange("longitude", Math.toDegrees(minLng), null, true, true), BooleanClause.Occur.SHOULD); lonF.add(NumericRangeFilter.newDoubleRange("longitude", null, Math.toDegrees(maxLng), true, true), BooleanClause.Occur.SHOULD); f.add(lonF, BooleanClause.Occur.MUST); } else { f.add(NumericRangeFilter.newDoubleRange("longitude", Math.toDegrees(minLng), Math.toDegrees(maxLng), true, true), BooleanClause.Occur.MUST); } return f; } /** User runs a query and counts facets. */ public FacetResult search() throws IOException { FacetsCollector fc = new FacetsCollector(); searcher.search(new MatchAllDocsQuery(), fc); Facets facets = new DoubleRangeFacetCounts("field", getDistanceValueSource(), fc, getBoundingBoxFilter(ORIGIN_LATITUDE, ORIGIN_LONGITUDE, 10.0), ONE_KM, TWO_KM, FIVE_KM, TEN_KM); return facets.getTopChildren(10, "field"); } /** User drills down on the specified range. */ public TopDocs drillDown(DoubleRange range) throws IOException { // Passing no baseQuery means we drill down on all // documents ("browse only"): DrillDownQuery q = new DrillDownQuery(null); final ValueSource vs = getDistanceValueSource(); q.add("field", range.getFilter(getBoundingBoxFilter(ORIGIN_LATITUDE, ORIGIN_LONGITUDE, range.max), vs)); DrillSideways ds = new DrillSideways(searcher, config, (TaxonomyReader) null) { @Override protected Facets buildFacetsResult(FacetsCollector drillDowns, FacetsCollector[] drillSideways, String[] drillSidewaysDims) throws IOException { assert drillSideways.length == 1; return new DoubleRangeFacetCounts("field", vs, drillSideways[0], ONE_KM, TWO_KM, FIVE_KM, TEN_KM); } }; return ds.search(q, 10).hits; } public void close() throws IOException { searcher.getIndexReader().close(); indexDir.close(); } /** Runs the search and drill-down examples and prints the results. */ @SuppressWarnings("unchecked") public static void main(String[] args) throws Exception { DistanceFacetsExample example = new DistanceFacetsExample(); example.index(); System.out.println("Distance facet counting example:"); System.out.println("-----------------------"); System.out.println(example.search()); System.out.println("\n"); System.out.println("Distance facet drill-down example (field/< 2 km):"); System.out.println("---------------------------------------------"); TopDocs hits = example.drillDown(example.TWO_KM); System.out.println(hits.totalHits + " totalHits"); example.close(); } }