IsSimpleTest.java

/*
 * Copyright (c) 2016 Vivid Solutions.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Eclipse Distribution License v. 1.0 which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 *
 * http://www.eclipse.org/org/documents/edl-v10.php.
 */
package org.locationtech.jts.operation;

import org.locationtech.jts.algorithm.BoundaryNodeRule;
import org.locationtech.jts.geom.Coordinate;
import org.locationtech.jts.geom.Geometry;
import org.locationtech.jts.geom.GeometryFactory;
import org.locationtech.jts.io.ParseException;
import org.locationtech.jts.io.WKTReader;

import junit.framework.TestCase;
import junit.textui.TestRunner;


/**
 * Tests {@link IsSimpleOp} with different {@link BoundaryNodeRule}s.
 *
 * @author Martin Davis
 * @version 1.7
 */
public class IsSimpleTest
    extends TestCase
{
  private static final double TOLERANCE = 0.00005;

  public static void main(String args[]) {
    TestRunner.run(IsSimpleTest.class);
  }

  private GeometryFactory fact = new GeometryFactory();
  private WKTReader rdr = new WKTReader(fact);

  public IsSimpleTest(String name)
  {
    super(name);
  }

  /**
   * 2 LineStrings touching at an endpoint
   * @throws Exception
   */
  public void test2TouchAtEndpoint() throws Exception {
		String a = "MULTILINESTRING((0 1, 1 1, 2 1), (0 0, 1 0, 2 1))";
		runIsSimpleTest(a, BoundaryNodeRule.MOD2_BOUNDARY_RULE, true,
				new Coordinate(2, 1));
		runIsSimpleTest(a, BoundaryNodeRule.ENDPOINT_BOUNDARY_RULE, true,
				new Coordinate(2, 1));
	}

  /**
   * 3 LineStrings touching at an endpoint.
   * 
   * @throws Exception
   */
  public void test3TouchAtEndpoint() throws Exception {
		String a = "MULTILINESTRING ((0 1, 1 1, 2 1),   (0 0, 1 0, 2 1),  (0 2, 1 2, 2 1))";

		// rings are simple under all rules
		runIsSimpleTest(a, BoundaryNodeRule.MOD2_BOUNDARY_RULE, true,
				new Coordinate(2, 1));
		runIsSimpleTest(a, BoundaryNodeRule.ENDPOINT_BOUNDARY_RULE, true,
				new Coordinate(2, 1));
	}

	public void testCross() throws Exception {
		String a = "MULTILINESTRING ((20 120, 120 20), (20 20, 120 120))";
		runIsSimpleTest(a, BoundaryNodeRule.MOD2_BOUNDARY_RULE, false,
				new Coordinate(70, 70));
		runIsSimpleTest(a, BoundaryNodeRule.ENDPOINT_BOUNDARY_RULE, false,
				new Coordinate(70, 70));
	}


  public void testMultiLineStringWithRingTouchAtEndpoint()
      throws Exception
  {
    String a = "MULTILINESTRING ((100 100, 20 20, 200 20, 100 100), (100 200, 100 100))";

    // under Mod-2, the ring has no boundary, so the line intersects the interior ==> not simple
    runIsSimpleTest(a, BoundaryNodeRule.MOD2_BOUNDARY_RULE,      false,  new Coordinate(100, 100)  );
    // under Endpoint, the ring has a boundary point, so the line does NOT intersect the interior ==> simple
    runIsSimpleTest(a, BoundaryNodeRule.ENDPOINT_BOUNDARY_RULE,  true  );
  }

  public void testRing()
      throws Exception
  {
    String a = "LINESTRING (100 100, 20 20, 200 20, 100 100)";

    // rings are simple under all rules
    runIsSimpleTest(a, BoundaryNodeRule.MOD2_BOUNDARY_RULE,      true  );
    runIsSimpleTest(a, BoundaryNodeRule.ENDPOINT_BOUNDARY_RULE,  true  );
  }


  private void runIsSimpleTest(String wkt, BoundaryNodeRule bnRule, boolean expectedResult)
      throws ParseException
  {
    runIsSimpleTest(wkt, bnRule, expectedResult, null);
  }

  private void runIsSimpleTest(String wkt, BoundaryNodeRule bnRule, boolean expectedResult,
                               Coordinate expectedLocation)
      throws ParseException
  {
    Geometry g = rdr.read(wkt);
    IsSimpleOp op = new IsSimpleOp(g, bnRule);
    boolean isSimple = false;
    isSimple = op.isSimple();
    Coordinate nonSimpleLoc = op.getNonSimpleLocation();

    // if geom is not simple, should have a valid location
    assertTrue(isSimple || nonSimpleLoc != null);

    assertTrue(expectedResult == isSimple);

    if (! isSimple && expectedLocation != null) {
      assertTrue(expectedLocation.distance(nonSimpleLoc) < TOLERANCE);
    }
  }

}