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 * 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
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 *     http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.lucene.spatial.prefix.tree;

import java.text.ParseException;
import java.util.Map;

import org.apache.lucene.util.Version;
import org.locationtech.spatial4j.context.SpatialContext;
import org.locationtech.spatial4j.distance.DistanceUtils;

Abstract Factory for creating SpatialPrefixTree instances with useful defaults and passed on configurations defined in a Map.
@lucene.experimental
/** * Abstract Factory for creating {@link SpatialPrefixTree} instances with useful * defaults and passed on configurations defined in a Map. * * @lucene.experimental */
public abstract class SpatialPrefixTreeFactory { private static final double DEFAULT_GEO_MAX_DETAIL_KM = 0.001;//1m public static final String PREFIX_TREE = "prefixTree"; public static final String MAX_LEVELS = "maxLevels"; public static final String MAX_DIST_ERR = "maxDistErr"; public static final String VERSION = "version"; protected Map<String, String> args; protected SpatialContext ctx; protected Integer maxLevels; private Version version;
The factory is looked up via "prefixTree" in args, expecting "geohash" or "quad". If it's neither of these, then "geohash" is chosen for a geo context, otherwise "quad" is chosen. The "version" arg, if present, is parsed with Version and the prefix tree might be sensitive to it.
/** * The factory is looked up via "prefixTree" in args, expecting "geohash" or "quad". * If it's neither of these, then "geohash" is chosen for a geo context, otherwise "quad" is chosen. * The "version" arg, if present, is parsed with {@link Version} and the prefix tree might be sensitive to it. */
public static SpatialPrefixTree makeSPT(Map<String,String> args, ClassLoader classLoader, SpatialContext ctx) { //TODO refactor to use Java SPI like how Lucene already does for codecs/postingsFormats, etc SpatialPrefixTreeFactory instance; String cname = args.get(PREFIX_TREE); if (cname == null) cname = ctx.isGeo() ? "geohash" : "quad"; if ("geohash".equalsIgnoreCase(cname)) instance = new GeohashPrefixTree.Factory(); else if ("quad".equalsIgnoreCase(cname)) instance = new QuadPrefixTree.Factory(); else if ("packedQuad".equalsIgnoreCase(cname)) instance = new PackedQuadPrefixTree.Factory(); else if ("s2".equalsIgnoreCase(cname)) instance = new S2PrefixTree.Factory(); else { try { Class<?> c = classLoader.loadClass(cname); instance = (SpatialPrefixTreeFactory) c.newInstance(); } catch (Exception e) { throw new RuntimeException(e); } } instance.init(args, ctx); return instance.newSPT(); } protected void init(Map<String, String> args, SpatialContext ctx) { this.args = args; this.ctx = ctx; initVersion(); initMaxLevels(); } protected void initVersion() { String versionStr = args.get(VERSION); try { setVersion(versionStr == null ? Version.LATEST : Version.parseLeniently(versionStr)); } catch (ParseException e) { throw new RuntimeException(e); } } protected void initMaxLevels() { String mlStr = args.get(MAX_LEVELS); if (mlStr != null) { maxLevels = Integer.valueOf(mlStr); return; } double degrees; String maxDetailDistStr = args.get(MAX_DIST_ERR); if (maxDetailDistStr == null) { if (!ctx.isGeo()) { return;//let default to max } degrees = DistanceUtils.dist2Degrees(DEFAULT_GEO_MAX_DETAIL_KM, DistanceUtils.EARTH_MEAN_RADIUS_KM); } else { degrees = Double.parseDouble(maxDetailDistStr); } maxLevels = getLevelForDistance(degrees); }
Set the version of Lucene this tree should mimic the behavior for for analysis.
/** * Set the version of Lucene this tree should mimic the behavior for for analysis. */
public void setVersion(Version v) { version = v; }
Return the version of Lucene this tree will mimic the behavior of for analysis.
/** * Return the version of Lucene this tree will mimic the behavior of for analysis. */
public Version getVersion() { return version; } /** Calls {@link SpatialPrefixTree#getLevelForDistance(double)}. */ protected abstract int getLevelForDistance(double degrees); protected abstract SpatialPrefixTree newSPT(); }