GeometryFunction.java

/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2002-2010, 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.geopkg.geom;

import java.io.IOException;
import java.sql.SQLException;
import org.sqlite.Function;

/**
 * An sqlite function that operates on a Geopackage Geometry BLOB.
 * 
 * @author Justin Deoliveira
 * @author Niels Charlier
 */
public abstract class GeometryFunction extends Function {
        
    public abstract Object execute(GeoPkgGeomReader reader) throws IOException;

    @Override
    protected void xFunc() throws SQLException {
        if (args() != 1) {
            throw new SQLException("Geometry Function expects one argument.");
        }
        
        Object res;
        try {
            res = execute(new GeoPkgGeomReader(value_blob(0)));
        } catch (IOException e) {
            throw new SQLException(e);
        }
        
        if (res == null) {
            result();
        } else if (res instanceof Integer) {
           result((Integer) res);
        } else if (res instanceof Double) {
            result((Double) res);
        } else if (res instanceof String) {
            result((String) res);
        } else if (res instanceof Long) {
           result((Long) res);
        } else if (res instanceof byte[]) {
           result((byte[]) res);
        } else if (res instanceof Boolean) {
            result((Boolean) res ? 1 : 0 );
        }
    }

}