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/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch 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.elasticsearch.index.query;

import org.apache.lucene.search.Filter;
import org.elasticsearch.ElasticsearchIllegalArgumentException;
import org.elasticsearch.ElasticsearchParseException;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.geo.GeoHashUtils;
import org.elasticsearch.common.geo.GeoPoint;
import org.elasticsearch.common.geo.GeoUtils;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.unit.DistanceUnit;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.common.xcontent.XContentParser.Token;
import org.elasticsearch.index.cache.filter.support.CacheKeyFilter;
import org.elasticsearch.index.mapper.FieldMapper;
import org.elasticsearch.index.mapper.MapperService;
import org.elasticsearch.index.mapper.core.StringFieldMapper;
import org.elasticsearch.index.mapper.geo.GeoPointFieldMapper;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * A geohash cell filter that filters {@link GeoPoint}s by their geohashes. Basically the a
 * Geohash prefix is defined by the filter and all geohashes that are matching this
 * prefix will be returned. The neighbors flag allows to filter
 * geohashes that surround the given geohash. In general the neighborhood of a
 * geohash is defined by its eight adjacent cells.
* The structure of the {@link GeohashCellFilter} is defined as: *
 * "geohash_bbox" {
 *     "field":"location",
 *     "geohash":"u33d8u5dkx8k",
 *     "neighbors":false
 * }
 * 
*/ public class GeohashCellFilter { public static final String NAME = "geohash_cell"; public static final String NEIGHBORS = "neighbors"; public static final String PRECISION = "precision"; public static final String CACHE = "_cache"; public static final String CACHE_KEY = "_cache_key"; /** * Create a new geohash filter for a given set of geohashes. In general this method * returns a boolean filter combining the geohashes OR-wise. * * @param context Context of the filter * @param fieldMapper field mapper for geopoints * @param geohash mandatory geohash * @param geohashes optional array of additional geohashes * @return a new GeoBoundinboxfilter */ public static Filter create(QueryParseContext context, GeoPointFieldMapper fieldMapper, String geohash, @Nullable List geohashes) { if (fieldMapper.geoHashStringMapper() == null) { throw new ElasticsearchIllegalArgumentException("geohash filter needs geohash_prefix to be enabled"); } StringFieldMapper geoHashMapper = fieldMapper.geoHashStringMapper(); if (geohashes == null || geohashes.size() == 0) { return geoHashMapper.termFilter(geohash, context); } else { geohashes.add(geohash); return geoHashMapper.termsFilter(geohashes, context); } } /** * Builder for a geohashfilter. It needs the fields fieldname and * geohash to be set. the default for a neighbor filteing is * false. */ public static class Builder extends BaseFilterBuilder { // we need to store the geohash rather than the corresponding point, // because a transformation from a geohash to a point an back to the // geohash will extend the accuracy of the hash to max precision // i.e. by filing up with z's. private String field; private String geohash; private int levels = -1; private boolean neighbors; private Boolean cache; private String cacheKey; public Builder(String field) { this(field, null, false); } public Builder(String field, GeoPoint point) { this(field, point.geohash(), false); } public Builder(String field, String geohash) { this(field, geohash, false); } public Builder(String field, String geohash, boolean neighbors) { super(); this.field = field; this.geohash = geohash; this.neighbors = neighbors; } public Builder point(GeoPoint point) { this.geohash = point.getGeohash(); return this; } public Builder point(double lat, double lon) { this.geohash = GeoHashUtils.encode(lat, lon); return this; } public Builder geohash(String geohash) { this.geohash = geohash; return this; } public Builder precision(int levels) { this.levels = levels; return this; } public Builder precision(String precision) { double meters = DistanceUnit.parse(precision, DistanceUnit.DEFAULT, DistanceUnit.METERS); return precision(GeoUtils.geoHashLevelsForPrecision(meters)); } public Builder neighbors(boolean neighbors) { this.neighbors = neighbors; return this; } public Builder field(String field) { this.field = field; return this; } /** * Should the filter be cached or not. Defaults to false. */ public Builder cache(boolean cache) { this.cache = cache; return this; } public Builder cacheKey(String cacheKey) { this.cacheKey = cacheKey; return this; } @Override protected void doXContent(XContentBuilder builder, Params params) throws IOException { builder.startObject(NAME); if (neighbors) { builder.field(NEIGHBORS, neighbors); } if(levels > 0) { builder.field(PRECISION, levels); } if (cache != null) { builder.field(CACHE, cache); } if (cacheKey != null) { builder.field(CACHE_KEY, cacheKey); } builder.field(field, geohash); builder.endObject(); } } public static class Parser implements FilterParser { @Inject public Parser() { } @Override public String[] names() { return new String[]{NAME, Strings.toCamelCase(NAME)}; } @Override public Filter parse(QueryParseContext parseContext) throws IOException, QueryParsingException { XContentParser parser = parseContext.parser(); String fieldName = null; String geohash = null; int levels = -1; boolean neighbors = false; boolean cache = false; CacheKeyFilter.Key cacheKey = null; XContentParser.Token token; if ((token = parser.currentToken()) != Token.START_OBJECT) { throw new ElasticsearchParseException(NAME + " must be an object"); } while ((token = parser.nextToken()) != Token.END_OBJECT) { if (token == Token.FIELD_NAME) { String field = parser.text(); if (PRECISION.equals(field)) { token = parser.nextToken(); if(token == Token.VALUE_NUMBER) { levels = parser.intValue(); } else if(token == Token.VALUE_STRING) { double meters = DistanceUnit.parse(parser.text(), DistanceUnit.DEFAULT, DistanceUnit.METERS); levels = GeoUtils.geoHashLevelsForPrecision(meters); } } else if (NEIGHBORS.equals(field)) { parser.nextToken(); neighbors = parser.booleanValue(); } else if (CACHE.equals(field)) { parser.nextToken(); cache = parser.booleanValue(); } else if (CACHE_KEY.equals(field)) { parser.nextToken(); cacheKey = new CacheKeyFilter.Key(parser.text()); } else { fieldName = field; token = parser.nextToken(); if(token == Token.VALUE_STRING) { // A string indicates either a gehash or a lat/lon string String location = parser.text(); if(location.indexOf(",")>0) { geohash = GeoUtils.parseGeoPoint(parser).geohash(); } else { geohash = location; } } else { geohash = GeoUtils.parseGeoPoint(parser).geohash(); } } } else { throw new ElasticsearchParseException("unexpected token [" + token + "]"); } } if (geohash == null) { throw new QueryParsingException(parseContext.index(), "no geohash value provided to geohash_cell filter"); } MapperService.SmartNameFieldMappers smartMappers = parseContext.smartFieldMappers(fieldName); if (smartMappers == null || !smartMappers.hasMapper()) { throw new QueryParsingException(parseContext.index(), "failed to find geo_point field [" + fieldName + "]"); } FieldMapper mapper = smartMappers.mapper(); if (!(mapper instanceof GeoPointFieldMapper)) { throw new QueryParsingException(parseContext.index(), "field [" + fieldName + "] is not a geo_point field"); } GeoPointFieldMapper geoMapper = ((GeoPointFieldMapper) mapper); if (!geoMapper.isEnableGeohashPrefix()) { throw new QueryParsingException(parseContext.index(), "can't execute geohash_cell on field [" + fieldName + "], geohash_prefix is not enabled"); } if(levels > 0) { int len = Math.min(levels, geohash.length()); geohash = geohash.substring(0, len); } Filter filter; if (neighbors) { filter = create(parseContext, geoMapper, geohash, GeoHashUtils.addNeighbors(geohash, new ArrayList(8))); } else { filter = create(parseContext, geoMapper, geohash, null); } if (cache) { filter = parseContext.cacheFilter(filter, cacheKey); } return filter; } } }




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