/**
* H2GIS is a library that brings spatial support to the H2 Database Engine
* <http://www.h2database.com>. H2GIS is developed by CNRS
* <http://www.cnrs.fr/>.
*
* This code is part of the H2GIS project. H2GIS 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 3.0 of the License.
*
* H2GIS 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 <http://www.gnu.org/licenses/>.
*
*
* For more information, please consult: <http://www.h2gis.org/>
* or contact directly: info_at_h2gis.org
*/
package org.h2gis.functions.spatial.aggregate;
import com.vividsolutions.jts.geom.*;
import org.h2.api.Aggregate;
import org.h2.value.Value;
import org.h2gis.api.AbstractFunction;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
/**
* Construct an array of Geometries.
*
* @author Nicolas Fortin
*/
public class ST_Accum extends AbstractFunction implements Aggregate {
private List<Geometry> toUnite = new LinkedList<Geometry>();
private int minDim = Integer.MAX_VALUE;
private int maxDim = Integer.MIN_VALUE;
public ST_Accum() {
addProperty(PROP_REMARKS, "This aggregate function returns a GeometryCollection "
+ "from a column of mixed dimension Geometries.\n"
+ "If there is only POINTs in the column of Geometries, a MULTIPOINT is returned. \n"
+ "Same process with LINESTRINGs and POLYGONs.");
}
@Override
public void init(Connection connection) throws SQLException {
}
@Override
public int getInternalType(int[] inputTypes) throws SQLException {
if (inputTypes.length != 1) {
throw new SQLException(ST_Accum.class.getSimpleName() + " expects 1 argument.");
}
if (inputTypes[0] != Value.GEOMETRY) {
throw new SQLException(ST_Accum.class.getSimpleName() + " expects a Geometry argument");
}
return Value.GEOMETRY;
}
private void feedDim(Geometry geometry) {
final int geomDim = geometry.getDimension();
maxDim = Math.max(maxDim, geomDim);
minDim = Math.min(minDim, geomDim);
}
/**
* Add geometry into an array to accumulate
* @param geom
*/
private void addGeometry(Geometry geom) {
if (geom != null) {
if (geom instanceof GeometryCollection) {
List<Geometry> toUnitTmp = new ArrayList<Geometry>(geom.getNumGeometries());
for (int i = 0; i < geom.getNumGeometries(); i++) {
toUnitTmp.add(geom.getGeometryN(i));
feedDim(geom.getGeometryN(i));
}
toUnite.addAll(toUnitTmp);
} else {
toUnite.add(geom);
feedDim(geom);
}
}
}
@Override
public void add(Object o) throws SQLException {
if (o instanceof Geometry) {
Geometry geom = (Geometry) o;
addGeometry(geom);
} else if (o != null) {
throw new SQLException("ST_Accum accepts only Geometry values. Input: " +
o.getClass().getSimpleName());
}
}
@Override
public GeometryCollection getResult() throws SQLException {
GeometryFactory factory = new GeometryFactory();
if(maxDim != minDim) {
return factory.createGeometryCollection(toUnite.toArray(new Geometry[toUnite.size()]));
} else {
switch (maxDim) {
case 0:
return factory.createMultiPoint(toUnite.toArray(new Point[toUnite.size()]));
case 1:
return factory.createMultiLineString(toUnite.toArray(new LineString[toUnite.size()]));
default:
return factory.createMultiPolygon(toUnite.toArray(new Polygon[toUnite.size()]));
}
}
}
}