/*
* The JTS Topology Suite is a collection of Java classes that
* implement the fundamental operations required to validate a given
* geo-spatial data set to a known topological specification.
*
* Copyright (C) 2001 Vivid Solutions
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* For more information, contact:
*
* Vivid Solutions
* Suite #1A
* 2328 Government Street
* Victoria BC V8T 5G5
* Canada
*
* (250)385-6040
* www.vividsolutions.com
*/
package com.vividsolutions.jts.index.quadtree;
import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.Envelope;
import com.vividsolutions.jts.util.Assert;
/**
* Represents a node of a {@link Quadtree}. Nodes contain
* items which have a spatial extent corresponding to the node's position
* in the quadtree.
*
* @version 1.7
*/
public class Node
extends NodeBase
{
public static Node createNode(Envelope env)
{
Key key = new Key(env);
Node node = new Node(key.getEnvelope(), key.getLevel());
return node;
}
public static Node createExpanded(Node node, Envelope addEnv)
{
Envelope expandEnv = new Envelope(addEnv);
if (node != null) expandEnv.expandToInclude(node.env);
Node largerNode = createNode(expandEnv);
if (node != null) largerNode.insertNode(node);
return largerNode;
}
private Envelope env;
private Coordinate centre;
private int level;
public Node(Envelope env, int level)
{
//this.parent = parent;
this.env = env;
this.level = level;
centre = new Coordinate();
centre.x = (env.getMinX() + env.getMaxX()) / 2;
centre.y = (env.getMinY() + env.getMaxY()) / 2;
}
public Envelope getEnvelope() { return env; }
protected boolean isSearchMatch(Envelope searchEnv)
{
return env.intersects(searchEnv);
}
/**
* Returns the subquad containing the envelope.
* Creates the subquad if
* it does not already exist.
*/
public Node getNode(Envelope searchEnv)
{
int subnodeIndex = getSubnodeIndex(searchEnv, centre);
// if subquadIndex is -1 searchEnv is not contained in a subquad
if (subnodeIndex != -1) {
// create the quad if it does not exist
Node node = getSubnode(subnodeIndex);
// recursively search the found/created quad
return node.getNode(searchEnv);
}
else {
return this;
}
}
/**
* Returns the smallest <i>existing</i>
* node containing the envelope.
*/
public NodeBase find(Envelope searchEnv)
{
int subnodeIndex = getSubnodeIndex(searchEnv, centre);
if (subnodeIndex == -1)
return this;
if (subnode[subnodeIndex] != null) {
// query lies in subquad, so search it
Node node = subnode[subnodeIndex];
return node.find(searchEnv);
}
// no existing subquad, so return this one anyway
return this;
}
void insertNode(Node node)
{
Assert.isTrue(env == null || env.contains(node.env));
//System.out.println(env);
//System.out.println(quad.env);
int index = getSubnodeIndex(node.env, centre);
//System.out.println(index);
if (node.level == level - 1) {
subnode[index] = node;
//System.out.println("inserted");
}
else {
// the quad is not a direct child, so make a new child quad to contain it
// and recursively insert the quad
Node childNode = createSubnode(index);
childNode.insertNode(node);
subnode[index] = childNode;
}
}
/**
* get the subquad for the index.
* If it doesn't exist, create it
*/
private Node getSubnode(int index)
{
if (subnode[index] == null) {
subnode[index] = createSubnode(index);
}
return subnode[index];
}
private Node createSubnode(int index)
{
// create a new subquad in the appropriate quadrant
double minx = 0.0;
double maxx = 0.0;
double miny = 0.0;
double maxy = 0.0;
switch (index) {
case 0:
minx = env.getMinX();
maxx = centre.x;
miny = env.getMinY();
maxy = centre.y;
break;
case 1:
minx = centre.x;
maxx = env.getMaxX();
miny = env.getMinY();
maxy = centre.y;
break;
case 2:
minx = env.getMinX();
maxx = centre.x;
miny = centre.y;
maxy = env.getMaxY();
break;
case 3:
minx = centre.x;
maxx = env.getMaxX();
miny = centre.y;
maxy = env.getMaxY();
break;
}
Envelope sqEnv = new Envelope(minx, maxx, miny, maxy);
Node node = new Node(sqEnv, level - 1);
return node;
}
}