/*
* 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.jtstest.geomop;
import com.vividsolutions.jts.geom.*;
import com.vividsolutions.jts.io.WKTWriter;
import com.vividsolutions.jts.operation.overlay.OverlayOp;
import com.vividsolutions.jts.operation.overlay.validate.OverlayResultValidator;
import com.vividsolutions.jtstest.testrunner.*;
/**
* A {@link GeometryOperation} which validates the result of overlay operations.
* If an invalid result is found, an exception is thrown (this is the most
* convenient and noticeable way of flagging the problem when using the TestRunner).
* All other Geometry methods are executed normally.
* <p>
* In order to eliminate the need to specify the precise result of an overlay,
* this class forces the final return value to be <tt>GEOMETRYCOLLECTION EMPTY</tt>.
* <p>
* This class can be used via the <tt>-geomop</tt> command-line option
* or by the <tt><geometryOperation></tt> XML test file setting.
*
* @author Martin Davis
*
*/
public class OverlayValidatedGeometryOperation
implements GeometryOperation
{
public static int overlayOpCode(String methodName)
{
if (methodName.equals("intersection")) return OverlayOp.INTERSECTION;
if (methodName.equals("union")) return OverlayOp.UNION;
if (methodName.equals("difference")) return OverlayOp.DIFFERENCE;
if (methodName.equals("symDifference")) return OverlayOp.SYMDIFFERENCE;
return -1;
}
private boolean returnEmptyGC = true;
private GeometryMethodOperation chainOp = new GeometryMethodOperation();
public OverlayValidatedGeometryOperation()
{
}
public Class getReturnType(String opName)
{
return chainOp.getReturnType(opName);
}
/**
* Creates a new operation which chains to the given {@link GeometryMethodOperation}
* for non-intercepted methods.
*
* @param chainOp the operation to chain to
*/
public OverlayValidatedGeometryOperation(GeometryMethodOperation chainOp)
{
this.chainOp = chainOp;
}
/**
* Invokes the named operation
*
* @param opName
* @param geometry
* @param args
* @return
* @throws Exception
* @see GeometryOperation#invoke
*/
public Result invoke(String opName, Geometry geometry, Object[] args)
throws Exception
{
int opCode = overlayOpCode(opName);
// if not an overlay op, do the default
if (opCode < 0) {
return chainOp.invoke(opName, geometry, args);
}
return invokeValidatedOverlayOp(opCode, geometry, args);
}
/**
* Invokes an overlay op, optionally using snapping,
* and optionally validating the result.
*
* @param opCode
* @param g0
* @param args
* @return
* @throws Exception
*/
public Result invokeValidatedOverlayOp(int opCode, Geometry g0, Object[] args)
throws Exception
{
Geometry result = null;
Geometry g1 = (Geometry) args[0];
result = invokeGeometryOverlayMethod(opCode, g0, g1);
// validate
validate(opCode, g0, g1, result);
areaValidate(g0, g1);
/**
* Return an empty GeometryCollection as the result.
* This allows the test case to avoid specifying an exact result
*/
if (returnEmptyGC) {
result = result.getFactory().createGeometryCollection(null);
}
return new GeometryResult(result);
}
private void validate(int opCode, Geometry g0, Geometry g1, Geometry result)
{
OverlayResultValidator validator = new OverlayResultValidator(g0, g1, result);
// check if computed result is valid
if (! validator.isValid(opCode)) {
Coordinate invalidLoc = validator.getInvalidLocation();
String msg = "Operation result is invalid [OverlayResultValidator] ( " + WKTWriter.toPoint(invalidLoc) + " )";
reportError(msg);
}
}
private static final double AREA_DIFF_TOL = 5.0;
private void areaValidate(Geometry g0, Geometry g1)
{
double areaDiff = areaDiff(g0, g1);
// System.out.println("Area diff = " + areaDiff);
if (Math.abs(areaDiff) > AREA_DIFF_TOL) {
String msg = "Operation result is invalid [AreaTest] (" + areaDiff + ")";
reportError(msg);
}
}
public static double areaDiff(Geometry g0, Geometry g1)
{
double areaA = g0.getArea();
double areaAdiffB = g0.difference(g1).getArea();
double areaAintB = g0.intersection(g1).getArea();
return areaA - areaAdiffB - areaAintB;
}
private void reportError(String msg)
{
// System.out.println(msg);
throw new RuntimeException(msg);
}
public static Geometry invokeGeometryOverlayMethod(int opCode, Geometry g0, Geometry g1)
{
switch (opCode) {
case OverlayOp.INTERSECTION: return g0.intersection(g1);
case OverlayOp.UNION: return g0.union(g1);
case OverlayOp.DIFFERENCE: return g0.difference(g1);
case OverlayOp.SYMDIFFERENCE: return g0.symDifference(g1);
}
throw new IllegalArgumentException("Unknown overlay op code");
}
}