/**********************************************************************
 * $Id: GeometryEditor.h 2556 2009-06-06 22:22:28Z strk $
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.refractions.net
 *
 * Copyright (C) 2001-2002 Vivid Solutions Inc.
 * Copyright (C) 2006 Refractions Research Inc.
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU Lesser General Public Licence as published
 * by the Free Software Foundation. 
 * See the COPYING file for more information.
 *
 **********************************************************************/

#ifndef GEOS_GEOM_UTIL_GEOMETRYEDITOR_H
#define GEOS_GEOM_UTIL_GEOMETRYEDITOR_H

#include <geos/export.h>

// Forward declarations
namespace geos {
	namespace geom {
		class Geometry;
		class GeometryFactory;
		class GeometryCollection;
		class Polygon;
		namespace util {
			class GeometryEditorOperation;
		}
	}
}


namespace geos {
namespace geom { // geos.geom
namespace util { // geos.geom.util

/**
 * Supports creating a new Geometry which is a modification of an existing one.
 * Geometry objects are intended to be treated as immutable.
 * This class allows you to "modify" a Geometry
 * by traversing it and creating a new Geometry with the same overall
 * structure but possibly modified components.
 *
 * The following kinds of modifications can be made:
 *
 * - the values of the coordinates may be changed.
 *   Changing coordinate values may make the result Geometry invalid;
 *   this is not checked by the GeometryEditor
 * - the coordinate lists may be changed
 *   (e.g. by adding or deleting coordinates).
 *   The modifed coordinate lists must be consistent with their original
 *   parent component
 *   (e.g. a LinearRing must always have at least 4 coordinates, and the
 *   first and last coordinate must be equal)
 * - components of the original geometry may be deleted
 *   (e.g. holes may be removed from a Polygon, or LineStrings removed
 *   from a MultiLineString). Deletions will be propagated up the component
 *   tree appropriately.
 * 
 * Note that all changes must be consistent with the original Geometry's
 * structure
 * (e.g. a Polygon cannot be collapsed into a LineString).
 *
 * The resulting Geometry is not checked for validity.
 * If validity needs to be enforced, the new Geometry's isValid should
 * be checked.
 *
 * @see Geometry::isValid
 *
 */
class GEOS_DLL GeometryEditor {
private:
	/**
	 * The factory used to create the modified Geometry
	 */
	const GeometryFactory* factory;

	Polygon* editPolygon(const Polygon *polygon,
			GeometryEditorOperation *operation);

	GeometryCollection* editGeometryCollection(
			const GeometryCollection *collection,
			GeometryEditorOperation *operation);

public:

	/**
	 * Creates a new GeometryEditor object which will create
	 * an edited Geometry with the same GeometryFactory as the
	 * input Geometry.
	 */
	GeometryEditor();

	/**
	 * Creates a new GeometryEditor object which will create
	 * the edited Geometry with the given GeometryFactory
	 *
	 * @param newFactory the GeometryFactory to create the edited
	 *                   Geometry with
	 */
	GeometryEditor(const GeometryFactory *newFactory);

	/**
	 * Edit the input Geometry with the given edit operation.
	 * Clients will create subclasses of GeometryEditorOperation or
	 * CoordinateOperation to perform required modifications.
	 *
	 * @param geometry the Geometry to edit
	 * @param operation the edit operation to carry out
	 * @return a new Geometry which is the result of the editing
	 *
	 */
	Geometry* edit(const Geometry *geometry,
			GeometryEditorOperation *operation); // final
};

} // namespace geos.geom.util
} // namespace geos.geom
} // namespace geos

//#ifdef GEOS_INLINE
//# include "geos/geom/util/GeometryEditor.inl"
//#endif

#endif

/**********************************************************************
 * $Log$
 * Revision 1.2  2006/03/24 09:52:41  strk
 * USE_INLINE => GEOS_INLINE
 *
 * Revision 1.1  2006/03/09 16:46:49  strk
 * geos::geom namespace definition, first pass at headers split
 *
 **********************************************************************/
