public abstract class SpatialPrefixTree extends Object
Modifier and Type | Field and Description |
---|---|
protected com.spatial4j.core.context.SpatialContext |
ctx |
protected int |
maxLevels |
protected static Charset |
UTF8 |
Constructor and Description |
---|
SpatialPrefixTree(com.spatial4j.core.context.SpatialContext ctx,
int maxLevels) |
Modifier and Type | Method and Description |
---|---|
abstract int |
getLevelForDistance(double dist)
Returns the level of the largest grid in which its longest side is less
than or equal to the provided distance (in degrees).
|
int |
getMaxLevels() |
abstract Node |
getNode(byte[] bytes,
int offset,
int len) |
Node |
getNode(byte[] bytes,
int offset,
int len,
Node target) |
protected Node |
getNode(com.spatial4j.core.shape.Point p,
int level) |
abstract 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.
|
protected List<Node> |
getNodesAltPoint(com.spatial4j.core.shape.Point p,
int detailLevel,
boolean inclParents)
Subclasses might override
getNodes(com.spatial4j.core.shape.Shape, int, boolean)
and check if the argument is a shape and if so, delegate
to this implementation, which calls getNode(com.spatial4j.core.shape.Point, int) and
then calls getNode(String) repeatedly if inclParents is true. |
com.spatial4j.core.context.SpatialContext |
getSpatialContext() |
Node |
getWorldNode()
Returns the level 0 cell which encompasses all spatial data.
|
static List<String> |
nodesToTokenStrings(Collection<Node> nodes)
Will add the trailing leaf byte for leaves.
|
String |
toString() |
protected static final Charset UTF8
protected final int maxLevels
protected final com.spatial4j.core.context.SpatialContext ctx
public SpatialPrefixTree(com.spatial4j.core.context.SpatialContext ctx, int maxLevels)
public com.spatial4j.core.context.SpatialContext getSpatialContext()
public int getMaxLevels()
public abstract int getLevelForDistance(double dist)
dist
acts as an error epsilon declaring the amount of detail needed in the
grid, such that you can get a grid with just the right amount of
precision.dist
- >= 0public Node getWorldNode()
getNode(String)
with "".
This cell is threadsafe, just like a spatial prefix grid is, although cells aren't
generally threadsafe.
TODO rename to getTopCell or is this fine?public abstract Node getNode(String token)
getWorldNode()
.
Precondition: Never called when token length > maxLevel.public abstract Node getNode(byte[] bytes, int offset, int len)
protected Node getNode(com.spatial4j.core.shape.Point p, int level)
public List<Node> getNodes(com.spatial4j.core.shape.Shape shape, int detailLevel, boolean inclParents)
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 getNodesAltPoint(com.spatial4j.core.shape.Point, int, boolean)
.
TODO consider another approach returning an iterator -- won't build up all cells in memory.protected final List<Node> getNodesAltPoint(com.spatial4j.core.shape.Point p, int detailLevel, boolean inclParents)
getNodes(com.spatial4j.core.shape.Shape, int, boolean)
and check if the argument is a shape and if so, delegate
to this implementation, which calls getNode(com.spatial4j.core.shape.Point, int)
and
then calls getNode(String)
repeatedly if inclParents is true.public static List<String> nodesToTokenStrings(Collection<Node> nodes)
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