org.apache.lucene.spatial.vector

Class PointVectorStrategy

java.lang.Object

org.apache.lucene.spatial.SpatialStrategy

org.apache.lucene.spatial.vector.PointVectorStrategy

public class PointVectorStrategy
extends SpatialStrategy

Simple SpatialStrategy which represents Points in two numeric fields. The Strategy's best feature is decent distance sort.

Characteristics:

• Only indexes points; just one per field value.
• Can query by a rectangle or circle.
• SpatialOperation.Intersects and SpatialOperation.IsWithin is supported.
• Requires DocValues for SpatialStrategy.makeDistanceValueSource(org.locationtech.spatial4j.shape.Point) and for searching with a Circle.

Implementation:

This is a simple Strategy. Search works with a pair of range queries on two DoublePoints representing x & y fields. A Circle query does the same bbox query but adds a ValueSource filter on SpatialStrategy.makeDistanceValueSource(org.locationtech.spatial4j.shape.Point).

One performance shortcoming with this strategy is that a scenario involving both a search using a Circle and sort will result in calculations for the spatial distance being done twice -- once for the filter and second for the sort.

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

Field Summary

Fields

Modifier and Type	Field and Description
static FieldType	DEFAULT_FIELDTYPE pointValues, docValues, and nothing else.
static String	SUFFIX_X
static String	SUFFIX_Y

Fields inherited from class org.apache.lucene.spatial.SpatialStrategy

ctx

Constructor Summary

Constructors

Constructor and Description
PointVectorStrategy(org.locationtech.spatial4j.context.SpatialContext ctx, String fieldNamePrefix, FieldType fieldType) Create a new instance configured with the provided FieldType options.

Method Summary

Modifier and Type	Method and Description
Field[]	createIndexableFields(org.locationtech.spatial4j.shape.Point point)
Field[]	createIndexableFields(org.locationtech.spatial4j.shape.Shape shape) Returns the IndexableField(s) from the shape that are to be added to the Document.
DoubleValuesSource	makeDistanceValueSource(org.locationtech.spatial4j.shape.Point queryPoint, double multiplier) Make a ValueSource returning the distance between the center of the indexed shape and queryPoint.
Query	makeQuery(SpatialArgs args) Make a Query based principally on SpatialOperation and Shape from the supplied args.
static PointVectorStrategy	newInstance(org.locationtech.spatial4j.context.SpatialContext ctx, String fieldNamePrefix) Create a new PointVectorStrategy instance that uses DoublePoint and DoublePoint.newRangeQuery(java.lang.String, double, double)

Methods inherited from class org.apache.lucene.spatial.SpatialStrategy

getFieldName, getSpatialContext, makeDistanceValueSource, makeRecipDistanceValueSource, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

DEFAULT_FIELDTYPE

public static FieldType DEFAULT_FIELDTYPE

pointValues, docValues, and nothing else.

SUFFIX_X

public static final String SUFFIX_X

See Also:

Constant Field Values

SUFFIX_Y

public static final String SUFFIX_Y

See Also:

Constant Field Values

Constructor Detail

PointVectorStrategy

public PointVectorStrategy(org.locationtech.spatial4j.context.SpatialContext ctx,
                           String fieldNamePrefix,
                           FieldType fieldType)

Create a new instance configured with the provided FieldType options. See DEFAULT_FIELDTYPE. a field type is used to articulate the desired options (namely pointValues, docValues, stored). Legacy numerics is configurable this way too.

Method Detail

newInstance

public static PointVectorStrategy newInstance(org.locationtech.spatial4j.context.SpatialContext ctx,
                                              String fieldNamePrefix)

Create a new PointVectorStrategy instance that uses DoublePoint and DoublePoint.newRangeQuery(java.lang.String, double, double)

createIndexableFields

public Field[] createIndexableFields(org.locationtech.spatial4j.shape.Shape shape)

Description copied from class: SpatialStrategy

Returns the IndexableField(s) from the shape that are to be added to the 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.

Specified by:

createIndexableFields in class SpatialStrategy

Returns:

Not null nor will it have null elements.

createIndexableFields

public Field[] createIndexableFields(org.locationtech.spatial4j.shape.Point point)

See Also:

createIndexableFields(org.locationtech.spatial4j.shape.Shape)

makeDistanceValueSource

public DoubleValuesSource makeDistanceValueSource(org.locationtech.spatial4j.shape.Point queryPoint,
                                                  double multiplier)

Description copied from class: SpatialStrategy

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.

Specified by:

makeDistanceValueSource in class SpatialStrategy

makeQuery

public Query makeQuery(SpatialArgs args)

Description copied from class: SpatialStrategy

Make a Query based principally on SpatialOperation and Shape from the supplied args. It should be constant scoring of 1.

Specified by:

makeQuery in class SpatialStrategy