/*
* 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.noding;
import java.util.*;
import com.vividsolutions.jts.index.SpatialIndex;
import com.vividsolutions.jts.index.chain.*;
import com.vividsolutions.jts.index.quadtree.Quadtree;
import com.vividsolutions.jts.index.strtree.STRtree;
import com.vividsolutions.jts.noding.SegmentIntersector;
import com.vividsolutions.jts.noding.SegmentString;
/**
* Intersects two sets of {@link SegmentString}s using a index based
* on {@link MonotoneChain}s and a {@link SpatialIndex}.
*
* @version 1.7
*/
public class MCIndexSegmentSetMutualIntersector
extends SegmentSetMutualIntersector
{
private List monoChains = new ArrayList();
/*
* The {@link SpatialIndex} used should be something that supports
* envelope (range) queries efficiently (such as a {@link Quadtree}
* or {@link STRtree}.
*/
private SpatialIndex index= new STRtree();
private int indexCounter = 0;
private int processCounter = 0;
// statistics
private int nOverlaps = 0;
public MCIndexSegmentSetMutualIntersector()
{
}
public List getMonotoneChains() { return monoChains; }
public SpatialIndex getIndex() { return index; }
public void setBaseSegments(Collection segStrings)
{
for (Iterator i = segStrings.iterator(); i.hasNext(); ) {
addToIndex((SegmentString) i.next());
}
}
private void addToIndex(SegmentString segStr)
{
List segChains = MonotoneChainBuilder.getChains(segStr.getCoordinates(), segStr);
for (Iterator i = segChains.iterator(); i.hasNext(); ) {
MonotoneChain mc = (MonotoneChain) i.next();
mc.setId(indexCounter++);
index.insert(mc.getEnvelope(), mc);
}
}
public void process(Collection segStrings)
{
processCounter = indexCounter + 1;
nOverlaps = 0;
monoChains.clear();
for (Iterator i = segStrings.iterator(); i.hasNext(); ) {
addToMonoChains((SegmentString) i.next());
}
intersectChains();
// System.out.println("MCIndexBichromaticIntersector: # chain overlaps = " + nOverlaps);
// System.out.println("MCIndexBichromaticIntersector: # oct chain overlaps = " + nOctOverlaps);
}
private void intersectChains()
{
MonotoneChainOverlapAction overlapAction = new SegmentOverlapAction(segInt);
for (Iterator i = monoChains.iterator(); i.hasNext(); ) {
MonotoneChain queryChain = (MonotoneChain) i.next();
List overlapChains = index.query(queryChain.getEnvelope());
for (Iterator j = overlapChains.iterator(); j.hasNext(); ) {
MonotoneChain testChain = (MonotoneChain) j.next();
queryChain.computeOverlaps(testChain, overlapAction);
nOverlaps++;
if (segInt.isDone()) return;
}
}
}
private void addToMonoChains(SegmentString segStr)
{
List segChains = MonotoneChainBuilder.getChains(segStr.getCoordinates(), segStr);
for (Iterator i = segChains.iterator(); i.hasNext(); ) {
MonotoneChain mc = (MonotoneChain) i.next();
mc.setId(processCounter++);
monoChains.add(mc);
}
}
public class SegmentOverlapAction
extends MonotoneChainOverlapAction
{
private SegmentIntersector si = null;
public SegmentOverlapAction(SegmentIntersector si)
{
this.si = si;
}
public void overlap(MonotoneChain mc1, int start1, MonotoneChain mc2, int start2)
{
SegmentString ss1 = (SegmentString) mc1.getContext();
SegmentString ss2 = (SegmentString) mc2.getContext();
si.processIntersections(ss1, start1, ss2, start2);
}
}
}