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* The JTS Topology Suite is a collection of Java classes that
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* implement the fundamental operations required to validate a given
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* geo-spatial data set to a known topological specification.
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* Copyright (C) 2001 Vivid Solutions
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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* For more information, contact:
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* 2328 Government Street
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* www.vividsolutions.com
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package com.vividsolutions.jts.operation.valid;
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import com.vividsolutions.jts.algorithm.*;
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import com.vividsolutions.jts.geom.*;
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import com.vividsolutions.jts.geomgraph.*;
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import com.vividsolutions.jts.index.sweepline.*;
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import com.vividsolutions.jts.util.*;
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* Tests whether any of a set of {@link LinearRing}s are
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* nested inside another ring in the set, using a {@link SweepLineIndex}
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* index to speed up the comparisons.
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public class SweeplineNestedRingTester
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private final CGAlgorithms cga = new CGAlgorithms();
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private GeometryGraph graph; // used to find non-node vertices
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private List rings = new ArrayList();
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private Envelope totalEnv = new Envelope();
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private SweepLineIndex sweepLine;
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private Coordinate nestedPt = null;
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public SweeplineNestedRingTester(GeometryGraph graph)
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public Coordinate getNestedPoint() { return nestedPt; }
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public void add(LinearRing ring)
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public boolean isNonNested()
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OverlapAction action = new OverlapAction();
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sweepLine.computeOverlaps(action);
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return action.isNonNested;
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private void buildIndex()
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sweepLine = new SweepLineIndex();
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for (int i = 0; i < rings.size(); i++) {
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LinearRing ring = (LinearRing) rings.get(i);
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Envelope env = ring.getEnvelopeInternal();
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SweepLineInterval sweepInt = new SweepLineInterval(env.getMinX(), env.getMaxX(), ring);
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sweepLine.add(sweepInt);
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private boolean isInside(LinearRing innerRing, LinearRing searchRing)
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Coordinate[] innerRingPts = innerRing.getCoordinates();
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Coordinate[] searchRingPts = searchRing.getCoordinates();
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if (! innerRing.getEnvelopeInternal().intersects(searchRing.getEnvelopeInternal()))
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Coordinate innerRingPt = IsValidOp.findPtNotNode(innerRingPts, searchRing, graph);
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Assert.isTrue(innerRingPt != null, "Unable to find a ring point not a node of the search ring");
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boolean isInside = cga.isPointInRing(innerRingPt, searchRingPts);
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nestedPt = innerRingPt;
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implements SweepLineOverlapAction
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boolean isNonNested = true;
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public void overlap(SweepLineInterval s0, SweepLineInterval s1)
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LinearRing innerRing = (LinearRing) s0.getItem();
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LinearRing searchRing = (LinearRing) s1.getItem();
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if (innerRing == searchRing) return;
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if (isInside(innerRing, searchRing))