FilterFunction_startAngle.java

package org.geotools.filter.function;

/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 * 
 *    (C) 2005-2008, Open Source Geospatial Foundation (OSGeo)
 *    
 *    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;
 *    version 2.1 of the License.
 *
 *    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.
 */

//this code is autogenerated - you shouldnt be modifying it!
import static org.geotools.filter.capability.FunctionNameImpl.parameter;

import org.geotools.filter.FunctionExpressionImpl;
import org.geotools.filter.capability.FunctionNameImpl;
import org.opengis.filter.capability.FunctionName;

import com.vividsolutions.jts.geom.CoordinateSequence;
import com.vividsolutions.jts.geom.LineString;

public class FilterFunction_startAngle extends FunctionExpressionImpl {
    //public static FunctionName NAME = new FunctionNameImpl("startAngle", "geometry");
    public static FunctionName NAME = new FunctionNameImpl("startAngle",
            parameter("degrees", Double.class),
            parameter("linestring", LineString.class));
    
    public FilterFunction_startAngle() {
        super(NAME);
    }

    public Object evaluate(Object feature) {
        LineString ls;

        try { // attempt to get value and perform conversion
            ls = (LineString) getExpression(0).evaluate(feature, LineString.class);
        } catch (Exception e) {
            // probably a type error
            throw new IllegalArgumentException(
                    "Filter Function problem for function startAngle argument #0 - expected type Geometry");
        }
        if (ls == null || ls.getNumPoints() == 1) {
            return null;
        }

        CoordinateSequence cs = ls.getCoordinateSequence();

        double dx = (cs.getX(1) - cs.getX(0));
        double dy = (cs.getY(1) - cs.getY(0));
        return -Math.toDegrees(Math.atan2(dy, dx));
    }
}