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 `DoublePoint`s 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

    All Methods Static Methods Instance Methods Concrete Methods
    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`

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