Java tutorial
/* * 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. */ package org.apache.lucene.spatial.vector; import java.io.IOException; import java.util.Objects; import org.apache.lucene.document.DoubleDocValuesField; import org.apache.lucene.document.DoublePoint; import org.apache.lucene.document.Field; import org.apache.lucene.document.FieldType; import org.apache.lucene.document.StoredField; import org.apache.lucene.index.DocValuesType; import org.apache.lucene.index.IndexReader; import org.apache.lucene.index.LeafReaderContext; import org.apache.lucene.search.BooleanClause; import org.apache.lucene.search.BooleanQuery; import org.apache.lucene.search.ConstantScoreQuery; import org.apache.lucene.search.ConstantScoreScorer; import org.apache.lucene.search.ConstantScoreWeight; import org.apache.lucene.search.DocIdSetIterator; import org.apache.lucene.search.DoubleValues; import org.apache.lucene.search.DoubleValuesSource; import org.apache.lucene.search.IndexSearcher; import org.apache.lucene.search.Query; import org.apache.lucene.search.QueryVisitor; import org.apache.lucene.search.ScoreMode; import org.apache.lucene.search.Scorer; import org.apache.lucene.search.TwoPhaseIterator; import org.apache.lucene.search.Weight; import org.apache.lucene.spatial.SpatialStrategy; import org.apache.lucene.spatial.query.SpatialArgs; import org.apache.lucene.spatial.query.SpatialOperation; import org.apache.lucene.spatial.query.UnsupportedSpatialOperation; import org.locationtech.spatial4j.context.SpatialContext; import org.locationtech.spatial4j.shape.Circle; import org.locationtech.spatial4j.shape.Point; import org.locationtech.spatial4j.shape.Rectangle; import org.locationtech.spatial4j.shape.Shape; /** * Simple {@link SpatialStrategy} which represents Points in two numeric fields. * The Strategy's best feature is decent distance sort. * * <p> * <b>Characteristics:</b> * <br> * <ul> * <li>Only indexes points; just one per field value.</li> * <li>Can query by a rectangle or circle.</li> * <li>{@link * org.apache.lucene.spatial.query.SpatialOperation#Intersects} and {@link * SpatialOperation#IsWithin} is supported.</li> * <li>Requires DocValues for * {@link #makeDistanceValueSource(org.locationtech.spatial4j.shape.Point)} and for * searching with a Circle.</li> * </ul> * * <p> * <b>Implementation:</b> * <p> * This is a simple Strategy. Search works with a pair of range queries on two {@link DoublePoint}s representing * x & y fields. A Circle query does the same bbox query but adds a * ValueSource filter on * {@link #makeDistanceValueSource(org.locationtech.spatial4j.shape.Point)}. * <p> * One performance shortcoming with this strategy is that a scenario involving * both a search using a Circle and sort will result in calculations for the * spatial distance being done twice -- once for the filter and second for the * sort. * * @lucene.experimental */ public class PointVectorStrategy extends SpatialStrategy { // note: we use a FieldType to articulate the options we want on the field. We don't use it as-is with a Field, we // create more than one Field. /** * pointValues, docValues, and nothing else. */ public static FieldType DEFAULT_FIELDTYPE; static { // Default: pointValues + docValues FieldType type = new FieldType(); type.setDimensions(1, Double.BYTES);//pointValues (assume Double) type.setDocValuesType(DocValuesType.NUMERIC);//docValues type.setStored(false); type.freeze(); DEFAULT_FIELDTYPE = type; } public static final String SUFFIX_X = "__x"; public static final String SUFFIX_Y = "__y"; private final String fieldNameX; private final String fieldNameY; private final int fieldsLen; private final boolean hasStored; private final boolean hasDocVals; private final boolean hasPointVals; /** * Create a new {@link PointVectorStrategy} instance that uses {@link DoublePoint} and {@link DoublePoint#newRangeQuery} */ public static PointVectorStrategy newInstance(SpatialContext ctx, String fieldNamePrefix) { return new PointVectorStrategy(ctx, fieldNamePrefix, DEFAULT_FIELDTYPE); } /** * Create a new instance configured with the provided FieldType options. See {@link #DEFAULT_FIELDTYPE}. * a field type is used to articulate the desired options (namely pointValues, docValues, stored). Legacy numerics * is configurable this way too. */ public PointVectorStrategy(SpatialContext ctx, String fieldNamePrefix, FieldType fieldType) { super(ctx, fieldNamePrefix); this.fieldNameX = fieldNamePrefix + SUFFIX_X; this.fieldNameY = fieldNamePrefix + SUFFIX_Y; int numPairs = 0; if ((this.hasStored = fieldType.stored())) { numPairs++; } if ((this.hasDocVals = fieldType.docValuesType() != DocValuesType.NONE)) { numPairs++; } if ((this.hasPointVals = fieldType.pointDataDimensionCount() > 0)) { numPairs++; } this.fieldsLen = numPairs * 2; } String getFieldNameX() { return fieldNameX; } String getFieldNameY() { return fieldNameY; } @Override public Field[] createIndexableFields(Shape shape) { if (shape instanceof Point) return createIndexableFields((Point) shape); throw new UnsupportedOperationException("Can only index Point, not " + shape); } /** @see #createIndexableFields(org.locationtech.spatial4j.shape.Shape) */ public Field[] createIndexableFields(Point point) { Field[] fields = new Field[fieldsLen]; int idx = -1; if (hasStored) { fields[++idx] = new StoredField(fieldNameX, point.getX()); fields[++idx] = new StoredField(fieldNameY, point.getY()); } if (hasDocVals) { fields[++idx] = new DoubleDocValuesField(fieldNameX, point.getX()); fields[++idx] = new DoubleDocValuesField(fieldNameY, point.getY()); } if (hasPointVals) { fields[++idx] = new DoublePoint(fieldNameX, point.getX()); fields[++idx] = new DoublePoint(fieldNameY, point.getY()); } assert idx == fields.length - 1; return fields; } @Override public DoubleValuesSource makeDistanceValueSource(Point queryPoint, double multiplier) { return new DistanceValueSource(this, queryPoint, multiplier); } @Override public Query makeQuery(SpatialArgs args) { if (!SpatialOperation.is(args.getOperation(), SpatialOperation.Intersects, SpatialOperation.IsWithin)) throw new UnsupportedSpatialOperation(args.getOperation()); Shape shape = args.getShape(); if (shape instanceof Rectangle) { Rectangle bbox = (Rectangle) shape; return new ConstantScoreQuery(makeWithin(bbox)); } else if (shape instanceof Circle) { Circle circle = (Circle) shape; Rectangle bbox = circle.getBoundingBox(); return new DistanceRangeQuery(makeWithin(bbox), makeDistanceValueSource(circle.getCenter()), circle.getRadius()); } else { throw new UnsupportedOperationException( "Only Rectangles and Circles are currently supported, " + "found [" + shape.getClass() + "]");//TODO } } /** * Constructs a query to retrieve documents that fully contain the input envelope. */ private Query makeWithin(Rectangle bbox) { BooleanQuery.Builder bq = new BooleanQuery.Builder(); BooleanClause.Occur MUST = BooleanClause.Occur.MUST; if (bbox.getCrossesDateLine()) { //use null as performance trick since no data will be beyond the world bounds bq.add(rangeQuery(fieldNameX, null/*-180*/, bbox.getMaxX()), BooleanClause.Occur.SHOULD); bq.add(rangeQuery(fieldNameX, bbox.getMinX(), null/*+180*/), BooleanClause.Occur.SHOULD); bq.setMinimumNumberShouldMatch(1);//must match at least one of the SHOULD } else { bq.add(rangeQuery(fieldNameX, bbox.getMinX(), bbox.getMaxX()), MUST); } bq.add(rangeQuery(fieldNameY, bbox.getMinY(), bbox.getMaxY()), MUST); return bq.build(); } /** * Returns a numeric range query based on FieldType * {@link DoublePoint#newRangeQuery} is used for indexes created using {@link DoublePoint} fields */ private Query rangeQuery(String fieldName, Double min, Double max) { if (hasPointVals) { if (min == null) { min = Double.NEGATIVE_INFINITY; } if (max == null) { max = Double.POSITIVE_INFINITY; } return DoublePoint.newRangeQuery(fieldName, min, max); } //TODO try doc-value range query? throw new UnsupportedOperationException("An index is required for this operation."); } private static class DistanceRangeQuery extends Query { final Query inner; final DoubleValuesSource distanceSource; final double limit; private DistanceRangeQuery(Query inner, DoubleValuesSource distanceSource, double limit) { this.inner = inner; this.distanceSource = distanceSource; this.limit = limit; } @Override public Query rewrite(IndexReader reader) throws IOException { Query rewritten = inner.rewrite(reader); if (rewritten == inner) return this; return new DistanceRangeQuery(rewritten, distanceSource, limit); } @Override public void visit(QueryVisitor visitor) { visitor.visitLeaf(this); } @Override public Weight createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) throws IOException { Weight w = inner.createWeight(searcher, scoreMode, 1f); return new ConstantScoreWeight(this, boost) { @Override public Scorer scorer(LeafReaderContext context) throws IOException { Scorer in = w.scorer(context); if (in == null) return null; DoubleValues v = distanceSource.getValues(context, DoubleValuesSource.fromScorer(in)); DocIdSetIterator approximation = in.iterator(); TwoPhaseIterator twoPhase = new TwoPhaseIterator(approximation) { @Override public boolean matches() throws IOException { return v.advanceExact(approximation.docID()) && v.doubleValue() <= limit; } @Override public float matchCost() { return 100; // distance calculation can be heavy! } }; return new ConstantScoreScorer(this, score(), scoreMode, twoPhase); } @Override public boolean isCacheable(LeafReaderContext ctx) { return distanceSource.isCacheable(ctx); } }; } @Override public String toString(String field) { return "DistanceRangeQuery(" + inner.toString(field) + "; " + distanceSource.toString() + " < " + limit + ")"; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; DistanceRangeQuery that = (DistanceRangeQuery) o; return Objects.equals(inner, that.inner) && Objects.equals(distanceSource, that.distanceSource) && limit == that.limit; } @Override public int hashCode() { return Objects.hash(inner, distanceSource, limit); } } }