/*
* 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.revolsys.geometry.geomgraph.index;
import java.util.Iterator;
import java.util.List;
import com.revolsys.geometry.geomgraph.Edge;
/**
* Finds all intersections in one or two sets of edges,
* using the straightforward method of
* comparing all segments.
* This algorithm is too slow for production use, but is useful for testing purposes.
* @version 1.7
*/
public class SimpleEdgeSetIntersector extends EdgeSetIntersector {
// statistics information
int nOverlaps;
public SimpleEdgeSetIntersector() {
}
@Override
public void computeIntersections(final List edges0, final List edges1,
final SegmentIntersector si) {
this.nOverlaps = 0;
for (final Iterator i0 = edges0.iterator(); i0.hasNext();) {
final Edge edge0 = (Edge)i0.next();
for (final Iterator i1 = edges1.iterator(); i1.hasNext();) {
final Edge edge1 = (Edge)i1.next();
computeIntersects(edge0, edge1, si);
}
}
}
@Override
public void computeIntersections(final List edges, final SegmentIntersector si,
final boolean testAllSegments) {
this.nOverlaps = 0;
for (final Iterator i0 = edges.iterator(); i0.hasNext();) {
final Edge edge0 = (Edge)i0.next();
for (final Iterator i1 = edges.iterator(); i1.hasNext();) {
final Edge edge1 = (Edge)i1.next();
if (testAllSegments || edge0 != edge1) {
computeIntersects(edge0, edge1, si);
}
}
}
}
/**
* Performs a brute-force comparison of every segment in each Edge.
* This has n^2 performance, and is about 100 times slower than using
* monotone chains.
*/
private void computeIntersects(final Edge e0, final Edge e1, final SegmentIntersector si) {
for (int i0 = 0; i0 < e0.getVertexCount() - 1; i0++) {
for (int i1 = 0; i1 < e1.getVertexCount() - 1; i1++) {
si.addIntersections(e0, i0, e1, i1);
}
}
}
}