org.hibernate.search.spatial.impl

Class SpatialHelper

java.lang.Object

org.hibernate.search.spatial.impl.SpatialHelper

public abstract class SpatialHelper
extends Object

Spatial fields, ids generator and geometric calculation methods for use in SpatialFieldBridge

Author:

Nicolas Helleringer, Mathieu Perez

See Also:

SpatialFieldBridgeByHash, SpatialFieldBridgeByRange

Method Summary

Modifier and Type	Method and Description
static int	findBestSpatialHashLevelForSearchRange(double searchRange) If point are searched at d distance from a point, a certain spatial hash cell level will problem spatial hash cell that are big enough to contain the search area but the smallest possible.
static String	formatFieldName(int spatialHashLevel, String fieldName)
static String	formatLatitude(String fieldName)
static String	formatLongitude(String fieldName)
static String	formatSpatialHashCellId(int xIndex, int yIndex)
static int	getCellIndex(double coordinate, double range, int spatialHashLevel) Generate a Cell Index on one axis
static String	getSpatialHashCellId(Point point, int spatialHashLevel) Generate a spatial hash cell id (with both cell index on both dimension in it) for a position
static List<String>	getSpatialHashCellsIds(Coordinates center, double radius, int spatialHashLevel) Generate a spatial hash cell ids list for the bounding box of a circular search area
static List<String>	getSpatialHashCellsIds(Point lowerLeft, Point upperRight, int spatialHashLevel) Generate a spatial hash cell ids list covered by a bounding box
static boolean	isSpatialField(String fieldName)
static boolean	isSpatialFieldLatitude(String fieldName)
static boolean	isSpatialFieldLongitude(String fieldName)
static double[]	projectToIndexSpace(Point point) Project a degree latitude/longitude point into a sinusoidal projection planar space for spatial hash cell ids computation
static String	stripSpatialFieldSuffix(String fieldName)

Methods inherited from class java.lang.Object

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

Method Detail

getCellIndex

public static int getCellIndex(double coordinate,
                               double range,
                               int spatialHashLevel)

Generate a Cell Index on one axis

Parameters:

coordinate - position to compute the Index for

range - range of the axis (-pi,pi)/(-90,90) => 2*pi/180 e.g

spatialHashLevel - Hox many time the range has been split in two

Returns:

the cell index on the axis

getSpatialHashCellId

public static String getSpatialHashCellId(Point point,
                                          int spatialHashLevel)

Generate a spatial hash cell id (with both cell index on both dimension in it) for a position

Parameters:

point - position to compute the spatial hash cell id for

spatialHashLevel - Hox many time the dimensions have been split in two

Returns:

the cell id for the point at the given spatial hash level

getSpatialHashCellsIds

public static List<String> getSpatialHashCellsIds(Point lowerLeft,
                                                  Point upperRight,
                                                  int spatialHashLevel)

Generate a spatial hash cell ids list covered by a bounding box

Parameters:

lowerLeft - lower left corner of the bounding box

upperRight - upper right corner of the bounding box

spatialHashLevel - spatial hash level of the wanted cell ids

Returns:

List of ids of the cells containing the point

getSpatialHashCellsIds

public static List<String> getSpatialHashCellsIds(Coordinates center,
                                                  double radius,
                                                  int spatialHashLevel)

Generate a spatial hash cell ids list for the bounding box of a circular search area

Parameters:

center - center of the search area

radius - radius of the search area

spatialHashLevel - spatial hash level of the wanted cell ids

Returns:

List of the ids of the cells covering the bounding box of the given search discus

findBestSpatialHashLevelForSearchRange

public static int findBestSpatialHashLevelForSearchRange(double searchRange)

If point are searched at d distance from a point, a certain spatial hash cell level will problem spatial hash cell that are big enough to contain the search area but the smallest possible. By returning this level we ensure 4 spatial hash cell maximum will be needed to cover the search area (2 max on each axis because of search area crossing fixed bonds of the spatial hash cells)

Parameters:

searchRange - search range to be covered by the spatial hash cells

Returns:

Return the best spatial hash level for a given search radius.

projectToIndexSpace

public static double[] projectToIndexSpace(Point point)

Project a degree latitude/longitude point into a sinusoidal projection planar space for spatial hash cell ids computation

Parameters:

point - point to be projected

Returns:

array of projected coordinates

formatFieldName

public static String formatFieldName(int spatialHashLevel,
                                     String fieldName)

formatLatitude

public static String formatLatitude(String fieldName)

formatLongitude

public static String formatLongitude(String fieldName)

isSpatialField

public static boolean isSpatialField(String fieldName)

isSpatialFieldLatitude

public static boolean isSpatialFieldLatitude(String fieldName)

isSpatialFieldLongitude

public static boolean isSpatialFieldLongitude(String fieldName)

stripSpatialFieldSuffix

public static String stripSpatialFieldSuffix(String fieldName)

formatSpatialHashCellId

public static String formatSpatialHashCellId(int xIndex,
                                             int yIndex)