Class SerializedDVStrategy

A SpatialStrategy based on serializing a Shape stored into BinaryDocValues. This is not at all fast; it's designed to be used in conjuction with another index based SpatialStrategy that is approximated(like RecursivePrefixTreeStrategy) to add precision or eventually make more specific / advanced calculations on the per-document geometry. The serialization uses Spatial4j's Spatial4n.IO.BinaryCodec.

Note

This API is experimental and might change in incompatible ways in the next release.

Inheritance
object
SpatialStrategy
SerializedDVStrategy
Inherited Members
Namespace: Lucene.Net.Spatial.Serialized
Assembly: Lucene.Net.Spatial.dll
Syntax
public class SerializedDVStrategy : SpatialStrategy

Constructors

SerializedDVStrategy(SpatialContext, string)

Constructs the spatial strategy with its mandatory arguments.

Declaration
public SerializedDVStrategy(SpatialContext ctx, string fieldName)
Parameters
Type Name Description
SpatialContext ctx
string fieldName
Exceptions
Type Condition
ArgumentNullException

ctx or fieldName is null or fieldName is empty.

Methods

CreateIndexableFields(IShape)

Returns the IndexableField(s) from the shape that are to be added to the Lucene.Net.Documents.Document. These fields are expected to be marked as indexed and not stored.

Note: If you want to store the shape as a string for retrieval in search results, you could add it like this: 
document.Add(new StoredField(fieldName, ctx.ToString(shape)));
The particular string representation used doesn't matter to the Strategy since it doesn't use it.
Declaration
public override Field[] CreateIndexableFields(IShape shape)
Parameters
Type Name Description
IShape shape
Returns
Type Description
Field[]

Not null nor will it have null elements.
Overrides
Exceptions
Type Condition
NotSupportedException

if given a shape incompatible with the strategy

MakeDistanceValueSource(IPoint, double)

Make a ValueSource returning the distance between the center of the indexed shape and queryPoint. If there are multiple indexed shapes then the closest one is chosen. The result is multiplied by multiplier, which conveniently is used to get the desired units.

Declaration
public override ValueSource MakeDistanceValueSource(IPoint queryPoint, double multiplier)
Parameters
Type Name Description
IPoint queryPoint
double multiplier
Returns
Type Description
ValueSource
Overrides

MakeFilter(SpatialArgs)

Returns a Lucene.Net.Search.Filter that should be used with Lucene.Net.Search.FilteredQuery.QUERY_FIRST_FILTER_STRATEGY. Use in another manner is likely to result in an NotSupportedException to prevent misuse because the filter can't efficiently work via iteration.

Declaration
public override Filter MakeFilter(SpatialArgs args)
Parameters
Type Name Description
SpatialArgs args
Returns
Type Description
Filter
Overrides

MakeQuery(SpatialArgs)

Make a Query based principally on SpatialOperation and Spatial4n.Shapes.IShape from the supplied args. The default implementation is

return new ConstantScoreQuery(MakeFilter(args));
Declaration
public override ConstantScoreQuery MakeQuery(SpatialArgs args)
Parameters
Type Name Description
SpatialArgs args
Returns
Type Description
ConstantScoreQuery
Overrides
Exceptions
Type Condition
NotSupportedException

If the strategy does not support the shape in args.
UnsupportedSpatialOperationException

If the strategy does not support the SpatialOperation in args.

MakeShapeValueSource()

Provides access to each shape per document as a ValueSource in which ObjectVal(int) returns a Spatial4n.Shapes.IShape.

Declaration
public virtual ValueSource MakeShapeValueSource()
Returns
Type Description
ValueSource