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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 <code>neighbors</code> flag allows to filter
* geohashes that surround the given geohash. In general the neighborhood of a
* geohash is defined by its eight adjacent cells.<br />
* The structure of the {@link GeohashCellFilter} is defined as:
* <pre>
* "geohash_bbox" {
* "field":"location",
* "geohash":"u33d8u5dkx8k",
* "neighbors":false
* }
* </pre>
*/
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<CharSequence> 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 <code>fieldname</code> and
* <code>geohash</code> to be set. the default for a neighbor filteing is
* <code>false</code>.
*/
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 <tt>false</tt>.
*/
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<CharSequence>(8)));
} else {
filter = create(parseContext, geoMapper, geohash, null);
}
if (cache) {
filter = parseContext.cacheFilter(filter, cacheKey);
}
return filter;
}
}
}