package org.geotools.caching.grid.spatialindex;
import org.geotools.caching.spatialindex.NodeIdentifier;
import org.geotools.caching.spatialindex.Region;
import org.geotools.caching.spatialindex.Shape;
/**
* Class allows you to iterator over the nodes
* that interest a given shape.
*
* @author Emily
* @since 1.2.0
*
*
*
* @source $URL$
*/
public class NodeCursor {
private GridRootNode root;
private int dimension;
private int[] mins ;
private int[] maxs ;
private int[] cursor;
private boolean hasNext;
public NodeCursor(GridRootNode root, Shape s){
this.dimension = root.getShape().getDimension();
this.root = root;
mins = new int[this.dimension];
maxs = new int[this.dimension];
cursor = new int[this.dimension];
findMatchingTiles(s, cursor, mins, maxs);
hasNext = true;
}
private void findMatchingTiles(Shape shape, int[] cursor, final int[] mins, final int[] maxs) {
Region shapembr = shape.getMBR();
for (int i = 0; i < this.dimension; i++) {
mins[i] = (int) ((shapembr.getLow(i) - this.root.getShape().getMBR().getLow(i)) / ((GridRootNode)this.root).tiles_size);
cursor[i] = mins[i];
maxs[i] = (int) ((shapembr.getHigh(i) - this.root.getShape().getMBR().getLow(i)) / ((GridRootNode)this.root).tiles_size);
int maxcnt = ((GridRootNode)this.root).getMaximumTileCount(i);
if (maxs[i] >= maxcnt){
//max tile count is 2 then we was the maximum index to be 1
maxs[i] = maxcnt-1;
}
}
}
/**
* The number of tiles that match the given shape
*
* @return
*/
public int getChildCount(){
int tiles = 1;
for (int i = 0; i < this.dimension; i++) {
tiles *= (maxs[i] - mins[i] + 1);
}
return tiles;
}
/**
*
* @return the next node id in the cursor; will return null if no more nodes
*/
public NodeIdentifier getNext(){
NodeIdentifier ret = null;
if (hasNext){
ret = root.getChildIdentifier(root.gridIndexToNodeId(cursor));
}
int dims = cursor.length;
for (int i = 0; i < dims; i++) {
cursor[i]++;
if (cursor[i] > maxs[i]) {
cursor[i] = mins[i];
if (i == (dims - 1)) {
//return null;
hasNext = false;
break;
}
} else {
break;
}
}
return ret;
}
}