/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2007-2011, 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.
*/
package org.geotools.filter;
import static org.geotools.filter.capability.FunctionNameImpl.parameter;
import org.geotools.filter.capability.FunctionNameImpl;
import org.opengis.feature.Attribute;
import org.opengis.filter.capability.FunctionName;
import org.opengis.filter.expression.Expression;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.GeometryCollection;
import com.vividsolutions.jts.geom.LineString;
import com.vividsolutions.jts.geom.Point;
import com.vividsolutions.jts.geom.Polygon;
/**
* Function which wraps an instance of geometry in its associatd multi geometry
* type.
*
* <p>
* <ul>
* <li>Point -> MultiPoint
* <li>LineString -> MultiLineString
* <li>Polygon -> MultiPolygon
* </ul>
* <br>
* <br>
* This function takes a single argument expression which must evaluate to an
* instanceof {@link com.vividsolutions.jts.geom.Geometry}.
* </p>
*
* @author Justin Deoliveira (The Open Planning Project)
*
*
*
*
*
* @source $URL$
*/
public class AsMultiGeometryFunctionExpression extends FunctionExpressionImpl {
public static FunctionName NAME = new FunctionNameImpl("asMultiGeometry",
parameter("multi-geometry",Geometry.class),
parameter("geometry",Geometry.class));
public AsMultiGeometryFunctionExpression() {
super(NAME);
}
public Object evaluate(Object obj) {
if (!(obj instanceof Attribute)) {
return null;
}
Attribute att = (Attribute) obj;
org.opengis.filter.expression.Expression arg = (Expression) getParameters()
.get(0);
Object value = arg.evaluate(att);
if (value != null) {
if (value instanceof Geometry) {
if (value instanceof GeometryCollection) {
return value;
}
return wrap((Geometry) value);
} else {
throw new IllegalArgumentException(
"function argument did not evaluate to "
+ Geometry.class);
}
}
return null;
}
private GeometryCollection wrap(Geometry geometry) {
if (geometry instanceof Point) {
return geometry.getFactory().createMultiPoint(
new Point[] { (Point) geometry });
} else if (geometry instanceof LineString) {
return geometry.getFactory().createMultiLineString(
new LineString[] { (LineString) geometry });
} else if (geometry instanceof Polygon) {
return geometry.getFactory().createMultiPolygon(
new Polygon[] { (Polygon) geometry });
}
throw new IllegalArgumentException(
"Unable to create multi geometry from " + geometry);
}
}