spatial
Class SimpleRTreeStrategy

java.lang.Object
  |
  +--spatial.SimpleRTreeStrategy

All Implemented Interfaces:

RTreeStrategy

public class SimpleRTreeStrategy

extends java.lang.Object

implements RTreeStrategy

Class providing the operations which determine the strategy of a simple r-tree.

Field Summary

protected java.util.BitSet	indicator Prepared indicator for the distribute operation.
protected int	m The minimum number of entries in a node after a split in %.
protected int	reinsertFactor Prepared indicator for the distribute operation.

Constructor Summary

SimpleRTreeStrategy()
Constructor.

SimpleRTreeStrategy(int reinsertFactor)
Constructor.

Method Summary

int	chooseSubtree(SpatialSearchTreeNode node, SpatialSearchTreeEntry obj) Determines the best subtree for inserting an new object according to the Gutman's original r-tree algorithm 1984.
java.util.BitSet	distribute(SpatialSearchTreeNode node, SpatialSearchTreeEntry entry) Distributes the entries of a node to two nodes according to a simple linear algorithm.
int	getMinimum() Gets the minimum percentage of entries.
int	getReinsertFactor(int height) Returns the percentage of objects which should be reinserted.
boolean	isOrdering() Return false because this it not an ordering strategy.
void	readParameters(java.io.DataInputStream in) Reads parameters from DataInputStream.
void	setMinimum(int m) Sets the minimum percentage of entries.
void	setReinsertFactor(int p) Sets the quota of entries to be reinserted.
void	sortAccordingTo(SpatialSearchTreeNode nd, double[] value, int left, int right) Performs the sorting of a node between two limits using quicksort and a given array with values.
void	sortAccordingTo(SpatialSearchTreeNode node, double[] value, int leftBorder, int left, int right) Performs the sorting of a node between two limits using quicksort and a given array with values.
void	sortForReinsert(SpatialSearchTreeNode node) Sorts the entries of the given node according to their distance to the center of the parent entry.
void	writeParameters(java.io.DataOutputStream out) Writes parameters to DataOutputStream.

Methods inherited from class java.lang.Object

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

Field Detail

reinsertFactor

protected int reinsertFactor

Prepared indicator for the distribute operation.

m

protected int m

The minimum number of entries in a node after a split in %.

indicator

protected java.util.BitSet indicator

Prepared indicator for the distribute operation.

Constructor Detail

SimpleRTreeStrategy

public SimpleRTreeStrategy()

Constructor.

SimpleRTreeStrategy

public SimpleRTreeStrategy(int reinsertFactor)

Constructor.

Parameters:

reinsertFactor - percentage of objects which should be reinserted (0 = no reinsert)

Method Detail

chooseSubtree

public int chooseSubtree(SpatialSearchTreeNode node,
                         SpatialSearchTreeEntry obj)

Determines the best subtree for inserting an new object according to the Gutman's original r-tree algorithm 1984.

Specified by:

chooseSubtree in interface RTreeStrategy

Parameters:

node - non-leaf node where the object should to be inserted

obj - the new object or the reinserted entry

Returns:

the index of the subtree

distribute

public java.util.BitSet distribute(SpatialSearchTreeNode node,
                                   SpatialSearchTreeEntry entry)

Distributes the entries of a node to two nodes according to a simple linear algorithm.

Specified by:

distribute in interface RTreeStrategy

Parameters:

node - the node

entry - the entry describing the node

Returns:

Bitset indicating the entries which should leave the node

getMinimum

public int getMinimum()

Gets the minimum percentage of entries.

Specified by:

getMinimum in interface RTreeStrategy

Returns:

the percentage

getReinsertFactor

public int getReinsertFactor(int height)

Returns the percentage of objects which should be reinserted.

Specified by:

getReinsertFactor in interface RTreeStrategy

Returns:

the reinsert factor (0 = no reinsert)

isOrdering

public boolean isOrdering()

Return false because this it not an ordering strategy.

Specified by:

isOrdering in interface RTreeStrategy

Returns:

false

readParameters

public void readParameters(java.io.DataInputStream in)
                    throws java.io.IOException

Reads parameters from DataInputStream.

Specified by:

readParameters in interface RTreeStrategy

Parameters:

in - stream

Throws:

java.io.IOException

setMinimum

public void setMinimum(int m)

Sets the minimum percentage of entries.

Specified by:

setMinimum in interface RTreeStrategy

Parameters:

m - the new value

setReinsertFactor

public void setReinsertFactor(int p)

Sets the quota of entries to be reinserted.

Specified by:

setReinsertFactor in interface RTreeStrategy

Parameters:

p - the new value

sortAccordingTo

public void sortAccordingTo(SpatialSearchTreeNode nd,
                            double[] value,
                            int left,
                            int right)

Performs the sorting of a node between two limits using quicksort and a given array with values.

Parameters:

nd - the node

value - the array with the values

left - left index

right - right index

sortAccordingTo

public void sortAccordingTo(SpatialSearchTreeNode node,
                            double[] value,
                            int leftBorder,
                            int left,
                            int right)

Performs the sorting of a node between two limits using quicksort and a given array with values.

Parameters:

value - the array with the values

leftBorder - the index of the first entry to be sorted

left - left index

right - right index

sortForReinsert

public void sortForReinsert(SpatialSearchTreeNode node)

Sorts the entries of the given node according to their distance to the center of the parent entry. The reinsert factor controls the number of exactly sorted entries. The object that should be reinserted are stored at the end of the node. The last entry should be reinserted first.

Specified by:

sortForReinsert in interface RTreeStrategy

Parameters:

node - the node

writeParameters

public void writeParameters(java.io.DataOutputStream out)
                     throws java.io.IOException

Writes parameters to DataOutputStream.

Specified by:

writeParameters in interface RTreeStrategy

Parameters:

out - stream

Throws:

java.io.IOException