/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2007-2008, Open Source Geospatial Foundation (OSGeo)
*
* 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;
* version 2.1 of the License.
*
* 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.
*/
package org.geotools.caching.grid.spatialindex;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.geotools.caching.spatialindex.AbstractSpatialIndex;
import org.geotools.caching.spatialindex.NodeIdentifier;
import org.geotools.caching.spatialindex.Region;
import org.geotools.caching.spatialindex.RegionNodeIdentifier;
import org.geotools.caching.spatialindex.Shape;
/**
* The root node of a grid, which has n GridNodes as children. As GridNodes do,
* it can store data too.
*
* @author Christophe Rousson, SoC 2007, CRG-ULAVAL
*
*
*
*
* @source $URL$
*/
public class GridRootNode extends GridNode {
private static final long serialVersionUID = 4675163856302389522L;
protected double tiles_size;
protected int[] tiles_number;
protected ArrayList<NodeIdentifier> children; // list of NodeIdentifiers
protected int childrenCapacity = -1;
/**
* No-arg constructor for serialization purpose. Deserialized nodes must
* call setIdentifier before using
*
*/
GridRootNode() {
super();
}
/**
* the mbr is read from the id;
*/
protected GridRootNode(int gridsize, RegionNodeIdentifier id) {
super(id);
init(gridsize);
}
private void init(int gridsize) {
int dims = getShape().getDimension();
Region mbr = (Region) getShape();
tiles_number = new int[dims];
double area = 1;
for (int i = 0; i < dims; i++) {
area *= (mbr.getHigh(i) - mbr.getLow(i));
}
tiles_size = Math.pow(area / gridsize, 1d / dims);
int newcapacity = 1;
for (int i = 0; i < dims; i++) {
int tmp;
double dtmp = (mbr.getHigh(i) - mbr.getLow(i)) / tiles_size;
tmp = (int) dtmp;
if (tmp < dtmp) {
tmp += 1;
}
tiles_number[i] = tmp;
newcapacity *= tmp;
}
assert (newcapacity >= gridsize);
// capacity = newcapacity;
childrenCapacity = newcapacity;
children = new ArrayList<NodeIdentifier>(childrenCapacity);
}
/**
* Creates the grid by appending children to this node.
*
*/
protected void split(GridSpatialIndex index) {
int dims = tiles_number.length;
double[] pos = new double[dims];
double[] nextpos = new double[dims];
Region mbr = (Region) getShape();
// int id = 0;
for (int i = 0; i < dims; i++) {
pos[i] = mbr.getLow(i);
nextpos[i] = pos[i] + tiles_size;
}
do {
Region reg = new Region(pos, nextpos);
RegionNodeIdentifier id = (RegionNodeIdentifier) index
.findUniqueInstance(new RegionNodeIdentifier(reg));
GridNode child = createNode(id);
index.writeNode(child);
this.children.add(child.getIdentifier());
// id++;
} while (increment(pos, nextpos));
}
public List<Integer> getChildren(Shape shape) {
Region mbr = (Region) getShape();
Region childMBR = shape.getMBR();
int dims = mbr.getDimension();
int[] gridminindex = new int[dims];
for (int i = 0; i < gridminindex.length; i++) {
if (childMBR.getLow(i) <= mbr.getLow(i)) {
gridminindex[i] = 0;
} else {
gridminindex[i] = (int) Math.floor((childMBR.getLow(i) - mbr.getLow(i))/ tiles_size);
}
}
int[] gridmaxindex = new int[dims];
for (int i = 0; i < gridminindex.length; i++) {
if (childMBR.getHigh(i) >= mbr.getHigh(i)) {
gridmaxindex[i] = tiles_number[i] - 1;
} else {
gridmaxindex[i] = (int) Math.floor((childMBR.getHigh(i) - mbr.getLow(i))/ tiles_size);
}
}
// want to iterate from gridminindex to gridmaxindex
int current[] = gridminindex.clone();
return iterate(current, gridminindex, gridmaxindex, 0);
}
private List<Integer> iterate(int current[], int min[], int max[], int index) {
ArrayList<Integer> values = new ArrayList<Integer>();
if (index >= min.length) {
return Collections.singletonList(new Integer(this.gridIndexToNodeId(current)));
}
for (int i = min[index]; i <= max[index]; i++) {
current[index] = i;
values.addAll(iterate(current, min, max, index + 1));
}
return values;
}
protected GridNode createNode(RegionNodeIdentifier id) {
// return new GridNode(grid, reg);
return new GridNode(id);
}
/**
* Computes sequentially the corner position of each tile in the grid.
*
* @param pos
* @param nextpos
* @return false if the upperright corner of the grid has been reached, true
* otherwise
*/
boolean increment(double[] pos, double[] nextpos) {
Region mbr = (Region) getShape();
int dims = pos.length;
if ((dims != tiles_number.length)
|| (nextpos.length != tiles_number.length)) {
throw new IllegalArgumentException(
"Cursor has not the same dimension as grid.");
}
for (int i = 0; i < dims; i++) {
if (((nextpos[i] - mbr.getHigh(i)) > 0)
|| (Math.abs(nextpos[i] - mbr.getHigh(i)) < AbstractSpatialIndex.EPSILON)) {
pos[i] = mbr.getLow(i);
nextpos[i] = pos[i] + tiles_size;
if (i == (dims - 1)) {
return false;
}
} else {
pos[i] = nextpos[i];
nextpos[i] = pos[i] + tiles_size;
break;
}
}
return true;
}
public String toString() {
StringBuffer sb = new StringBuffer();
// sb.append("GridRootNode: capacity:" + capacity + ", MBR:" + mbr);
sb.append("GridRootNode: MBR: " + this.getShape() + ", capacity: "
+ getCapacity());
return sb.toString();
}
public NodeIdentifier getChildIdentifier(int index)
throws IndexOutOfBoundsException {
return (NodeIdentifier) children.get(index);
}
public void setChildIdentifier(int index, NodeIdentifier id) {
children.set(index, id);
}
public int getChildrenCount() {
return children.size();
}
public int getLevel() {
return 1;
}
public boolean isIndex() {
if (children.isEmpty()) {
return false;
} else {
return true;
}
}
public boolean isLeaf() {
return !isIndex();
}
/**
* Converts an array of indexes into the id of a node.
*
* @param index
* @return
*/
public int gridIndexToNodeId(int[] index) {
if (index.length != tiles_number.length) {
throw new IllegalArgumentException("Argument has " + index.length
+ " dimensions whereas grid has " + tiles_number.length);
} else {
int result = 0;
int offset = 1;
for (int i = 0; i < index.length; i++) {
result += (offset * index[i]);
offset *= tiles_number[i];
}
return result;
}
}
/**
* Only clears data the root node; does not clear the children.
*/
public void clear() {
super.clear();
}
public String toReadableText() {
StringBuffer sb = new StringBuffer();
sb.append("RootNode *****");
sb.append(super.toReadableText());
return sb.toString();
}
/**
* The maximum of allowable nodes in the grid.
*
* @return
*/
public int getCapacity() {
return this.childrenCapacity;
}
/**
* The number of tiles/nodes in a given dimension.
*
* @param dim
* @return
*/
public int getMaximumTileCount(int dim) {
if (dim < 0 || dim > tiles_number.length) {
return -1;
}
return tiles_number[dim];
}
/**
* @returns the size of the children tiles
*/
public double getTileSize() {
return this.tiles_size;
}
// public void printGrid(){
// System.out.println(makePolygon((Region)this.getShape()));
//
// for(int i = 0; i < getChildrenCount(); i ++){
// NodeIdentifier id = this.getChildIdentifier(i);
// System.out.println(makePolygon((Region)id.getShape()));
// }
// }
//
// public String makePolygon(Region r){
// double minx = r.getLow(0);
// double maxx = r.getHigh(0);
// double miny = r.getLow(1);
// double maxy = r.getHigh(1);
// return "POLYGON(( " + minx + " " + miny + ", " + minx + " " + maxy + "," + maxx + " " + maxy + "," + maxx + " " + miny + "," + minx + " " + miny + "))";
// }
}