org.elasticsearch.common.lucene.spatial.prefix.tree
Class GeohashPrefixTree

java.lang.Object
  org.elasticsearch.common.lucene.spatial.prefix.tree.SpatialPrefixTree
      org.elasticsearch.common.lucene.spatial.prefix.tree.GeohashPrefixTree

public class GeohashPrefixTree
extends SpatialPrefixTree

A SpatialPrefixGrid based on Geohashes. Uses GeohashUtils to do all the geohash work.

Field Summary

Fields inherited from class org.elasticsearch.common.lucene.spatial.prefix.tree.SpatialPrefixTree

ctx, maxLevels, UTF8

Constructor Summary

GeohashPrefixTree(com.spatial4j.core.context.SpatialContext ctx, int maxLevels)

Method Summary

int	getLevelForDistance(double dist) Returns the level of the smallest grid size with a side length that is greater or equal to the provided distance.
static int	getMaxLevelsPossible() Any more than this and there's no point (double lat & lon are the same).
Node	getNode(byte[] bytes, int offset, int len)
Node	getNode(com.spatial4j.core.shape.Point p, int level)
Node	getNode(String token) The cell for the specified token.
List<Node>	getNodes(com.spatial4j.core.shape.Shape shape, int detailLevel, boolean inclParents) Gets the intersecting & including cells for the specified shape, without exceeding detail level.

Methods inherited from class org.elasticsearch.common.lucene.spatial.prefix.tree.SpatialPrefixTree

getMaxLevelForPrecision, getMaxLevels, getNode, getNodesAltPoint, getSpatialContext, getWorldNode, nodesToTokenStrings, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

GeohashPrefixTree

public GeohashPrefixTree(com.spatial4j.core.context.SpatialContext ctx,
                         int maxLevels)

Method Detail

getMaxLevelsPossible

public static int getMaxLevelsPossible()

Any more than this and there's no point (double lat & lon are the same).

getLevelForDistance

public int getLevelForDistance(double dist)

Description copied from class: SpatialPrefixTree

Returns the level of the smallest grid size with a side length that is greater or equal to the provided distance.

Specified by:

getLevelForDistance in class SpatialPrefixTree

Parameters:

dist - >= 0

Returns:

level [1-maxLevels]

getNode

public Node getNode(com.spatial4j.core.shape.Point p,
                    int level)

Overrides:

getNode in class SpatialPrefixTree

getNode

public Node getNode(String token)

Description copied from class: SpatialPrefixTree

The cell for the specified token. The empty string should be equal to SpatialPrefixTree.getWorldNode(). Precondition: Never called when token length > maxLevel.

Specified by:

getNode in class SpatialPrefixTree

getNode

public Node getNode(byte[] bytes,
                    int offset,
                    int len)

Specified by:

getNode in class SpatialPrefixTree

getNodes

public List<Node> getNodes(com.spatial4j.core.shape.Shape shape,
                           int detailLevel,
                           boolean inclParents)

Description copied from class: SpatialPrefixTree

Gets the intersecting & including cells for the specified shape, without exceeding detail level. The result is a set of cells (no dups), sorted. Unmodifiable.

This implementation checks if shape is a Point and if so uses an implementation that recursively calls Node.getSubCell(com.spatial4j.core.shape.Point). Cell subclasses ideally implement that method with a quick implementation, otherwise, subclasses should override this method to invoke SpatialPrefixTree.getNodesAltPoint(com.spatial4j.core.shape.Point, int, boolean). TODO consider another approach returning an iterator -- won't build up all cells in memory.

Overrides:

getNodes in class SpatialPrefixTree