package?rtree;

import?java.util.*;
import?java.io.*;

/**
?*?Implements?basic?functions?of?Node?interface.?Also?implements?splitting?functions.
?*?

?*?Created:?Tue?May?18?15:57:56?1999
?*?

?*?@author?Hadjieleftheriou?Marios
?*?@version?1.1
?*/
public?abstract?class?AbstractNode?implements?Node?{
????/**?Level?of?this?node.?Leaves?always?have?a?level?equal?to?0.?*/
????protected?int?level;

????/**?Parent?of?all?nodes.?*/
????protected?transient?RTree?tree;

????/**?The?pageNumber?where?the?parent?of?this?node?is?stored.?*/
????protected?int?parent;

????/**?The?pageNumber?where?this?node?is?stored.?*/
????protected?int?pageNumber;

????/**
?????*?All?node?data?are?stored?into?this?array.?It?must?have?a?size?of?nodeCapacity?+?1?to?hold
?????*?all?data?plus?an?overflow?HyperCube?when?the?node?must?be?split.
?????*/
????protected?HyperCube[]?data;

????/**
?????*?Holds?the?pageNumbers?containing?the?children?of?this?node.?Always?has?same?size?with?the?data?array.
?????*?If?this?is?a?Leaf?node?than?all?branches?should?point?to?the?real?data?objects.
?????*/
????protected?int[]?branches;

????/**?How?much?space?is?used?up?into?this?node.?If?equal?to?nodeCapacity?then?node?is?full.?*/
????protected?int?usedSpace;

//
//?Initialization.
//

????protected?AbstractNode（RTree?tree?int?parent?int?pageNumber?int?level）?{
	this.parent?=?parent;
	this.tree?=?tree;
	this.pageNumber?=?pageNumber;
	this.level?=?level;
	data?=?new?HyperCube[tree.getNodeCapacity（）+1];
	branches?=?new?int[tree.getNodeCapacity（）+1];
	usedSpace?=?0;
????}

//
//?Node?interface.
//

????/**
?????*?Returns?the?node?level.?Always?zero?for?leaf?nodes.
?????*
?????*?@return?Level?of?node.
?????*/
????public?int?getLevel（）?{
	return?level;
????}

????/**
?????*??Returns?true?if?this?node?is?the?root?node.
?????*/
????public?boolean?isRoot（）?{
	return?（parent?==?RTree.NIL）;
????}

????/**
?????*??Returns?true?if?this?node?is?an?Index.?Root?node?is?an?Index?too?unless?it?is?a?Leaf.
?????*/
????public?boolean?isIndex（）?{
	return?（level?!=?0）;
????}

????/**
?????*?Returns?true?if?this?node?is?a?Leaf.?Root?may?be?a?Leaf?too.
?????*/
????public?boolean?isLeaf（）?{
	return?（level?==?0）;
????}

????/**
?????*?Returns?the?mbb?of?all?HyperCubes?present?in?this?node.
?????*
?????*?@return?A?new?HyperCube?object?representing?the?mbb?of?this?node.
?????*/
????public?HyperCube?getNodeMbb（）?{
	if?（usedSpace?>?0）?{
	????HyperCube[]?h?=?new?HyperCube[usedSpace];
	????System.arraycopy（data?0?h?0?usedSpace）;
	????return?HyperCube.getUnionMbb（h）;
	}?else?{
	????return?new?HyperCube（new?Point（new?float[]?{0?0}）?new?Point（new?float[]?{0?0}））;
	}
????}

????/**
?????*?Returns?a?unique?id?for?this?node.?The?page?number?is?unique?for?every?node?but
?????*?it?doen‘t?signify?anything?about?where?in?the?path?from?the?root?this?node?lies?it?is?random.
?????*?This?function?returns?a?point?separated?list?of?page?numbers?from?the?root?up?to?the
?????*?current?node.?It?is?expensive?though