public FilteredQuery CreateFilteredQuery(ILuceneQueryService builder, LuceneQueryContext context, string type, JToken filter, Query toFilter)
{
if (type != "geo_bounding_box")
{
return(null);
}
if (!(toFilter is BooleanQuery booleanQuery))
{
return(null);
}
var queryObj = filter as JObject;
var first = queryObj.Properties().First();
var ctx = SpatialContext.Geo;
var maxLevels = 11; //results in sub-meter precision for geohash
// This can also be constructed from SpatialPrefixTreeFactory
SpatialPrefixTree grid = new GeohashPrefixTree(ctx, maxLevels);
var geoPropertyName = first.Name;
var strategy = new RecursivePrefixTreeStrategy(grid, geoPropertyName);
var boundingBox = (JObject)first.Value;
var topLeftProperty = boundingBox["top_left"] as JObject;
var bottomRightProperty = boundingBox["bottom_right"] as JObject;
if (topLeftProperty == null || bottomRightProperty == null)
{
return(null);
}
var left = topLeftProperty["lon"];
var top = topLeftProperty["lat"];
var bottom = bottomRightProperty["lat"];
var right = bottomRightProperty["lon"];
var rectangle = ctx.MakeRectangle((double)left, (double)right, (double)bottom, (double)top);
var args = new SpatialArgs(SpatialOperation.Intersects, rectangle);
var spatialQuery = strategy.MakeQuery(args);
var valueSource = strategy.MakeRecipDistanceValueSource(rectangle);
var valueSourceFilter = new ValueSourceFilter(new QueryWrapperFilter(spatialQuery), valueSource, 0, 1);
booleanQuery.Add(new FunctionQuery(valueSource), Occur.MUST);
return(new FilteredQuery(booleanQuery, valueSourceFilter));
}
public void Document_Writing_To_Index_Spatial_Data_And_Search_On_100km_Radius_RecursivePrefixTreeStrategy()
{
// NOTE: It is advised to use RecursivePrefixTreeStrategy, see:
// https://stackoverflow.com/a/13631289/694494
// Here's the Java sample code
// https://github.com/apache/lucene-solr/blob/branch_4x/lucene/spatial/src/test/org/apache/lucene/spatial/SpatialExample.java
SpatialContext ctx = SpatialContext.GEO;
int maxLevels = 11; //results in sub-meter precision for geohash
SpatialPrefixTree grid = new GeohashPrefixTree(ctx, maxLevels);
RecursivePrefixTreeStrategy strategy = new RecursivePrefixTreeStrategy(grid, GeoLocationFieldName);
// NOTE: The SpatialExample uses MatchAllDocsQuery however the strategy can create a query too, the source is here:
// https://github.com/apache/lucenenet/blob/master/src/Lucene.Net.Spatial/SpatialStrategy.cs#L124
// all that really does it take the filter created and creates a ConstantScoreQuery with it
// which probably makes sense because a 'Score' for a geo coord doesn't make a lot of sense.
RunTest(ctx, strategy, a => strategy.MakeQuery(a));
}
public FilteredQuery CreateFilteredQuery(ILuceneQueryService builder, LuceneQueryContext context, string type, JToken filter, Query toFilter)
{
if (type != "geo_distance")
{
return(null);
}
if (!(toFilter is BooleanQuery booleanQuery))
{
return(null);
}
var queryObj = filter as JObject;
if (queryObj.Properties().Count() != 2)
{
return(null);
}
var ctx = SpatialContext.Geo;
var maxLevels = 11; //results in sub-meter precision for geohash
// This can also be constructed from SpatialPrefixTreeFactory
SpatialPrefixTree grid = new GeohashPrefixTree(ctx, maxLevels);
JProperty distanceProperty = null;
JProperty geoProperty = null;
foreach (var jProperty in queryObj.Properties())
{
if (jProperty.Name.Equals("distance", StringComparison.Ordinal))
{
distanceProperty = jProperty;
}
else
{
geoProperty = jProperty;
}
}
if (distanceProperty == null || geoProperty == null)
{
return(null);
}
var strategy = new RecursivePrefixTreeStrategy(grid, geoProperty.Name);
if (!TryParseDistance((string)distanceProperty.Value, out var distanceDegrees))
{
return(null);
}
if (!TryGetPointFromJToken(geoProperty.Value, out var point))
{
return(null);
}
var circle = ctx.MakeCircle(point.X, point.Y, distanceDegrees);
var args = new SpatialArgs(SpatialOperation.Intersects, circle);
var spatialQuery = strategy.MakeQuery(args);
var valueSource = strategy.MakeRecipDistanceValueSource(circle);
var valueSourceFilter = new ValueSourceFilter(new QueryWrapperFilter(spatialQuery), valueSource, 0, 1);
booleanQuery.Add(new FunctionQuery(valueSource), Occur.MUST);
return(new FilteredQuery(booleanQuery, valueSourceFilter));
}
