| gvSIG desktop 1

/*

 * Created on 16-feb-2006

 *

 * gvSIG. Sistema de Informaci?n Geogr?fica de la Generalitat Valenciana

 *

 * Copyright (C) 2004 IVER T.I. and Generalitat Valenciana.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 *

 * This program 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,USA.

 *

 * For more information, contact:

 *

 *  Generalitat Valenciana

 *   Conselleria d'Infraestructures i Transport

 *   Av. Blasco Ib??ez, 50

 *   46010 VALENCIA

 *   SPAIN

 *

 *      +34 963862235

 *   gvsig@gva.es

 *      www.gvsig.gva.es

 *

 *    or

 *

 *   IVER T.I. S.A

 *   Salamanca 50

 *   46005 Valencia

 *   Spain

 *

 *   +34 963163400

 *   dac@iver.es

 */

/* CVS MESSAGES:

*

* $Id: ClipVisitor.java 4447 2006-03-15 18:35:56Z azabala $

* $Log$

* Revision 1.4  2006-03-15 18:30:39  azabala

* *** empty log message ***

*

* Revision 1.3  2006/03/14 18:32:46  fjp

* Cambio con LayerDefinition para que sea compatible con la definici?n de tablas tambi?n.

*

* Revision 1.2  2006/03/07 21:01:33  azabala

* *** empty log message ***

*

* Revision 1.1  2006/03/06 19:48:39  azabala

* *** empty log message ***

*

* Revision 1.2  2006/02/19 20:56:21  azabala

* *** empty log message ***

*

* Revision 1.1  2006/02/17 16:33:05  azabala

* *** empty log message ***

*

*

*/

package com.iver.gvsig.geoprocessing.impl.clip;

import com.iver.cit.gvsig.fmap.DriverException;

import com.iver.cit.gvsig.fmap.core.IGeometry;

import com.iver.cit.gvsig.fmap.drivers.ITableDefinition;

import com.iver.cit.gvsig.fmap.edition.EditionException;

import com.iver.cit.gvsig.fmap.edition.ISchemaManager;

import com.iver.cit.gvsig.fmap.edition.IWriter;

import com.iver.cit.gvsig.fmap.layers.FLayer;

import com.iver.cit.gvsig.fmap.layers.SelectableDataSource;

import com.iver.cit.gvsig.fmap.layers.layerOperations.AlphanumericData;

import com.iver.cit.gvsig.fmap.layers.layerOperations.VectorialData;

import com.iver.cit.gvsig.fmap.operations.strategies.FeatureVisitor;

import com.iver.cit.gvsig.fmap.operations.strategies.VisitException;

import com.iver.gvsig.geoprocessing.impl.jtsprocessors.FeaturePersisterProcessor;

import com.vividsolutions.jts.geom.Geometry;

/**

 * This class analyzes all features of a layer, clipping its geometries

 * with the convex hull of another layer.

 * If the geometry of the feature analyzed doesnt intersect with the convex

 * hull geometry, the clipvisitor will ignore it.

 * 

 * It intersects, computes intersection and creates a new feature with

 * the same attributes and the new intersection geometry.

 * @author azabala

 *

 */

public class ClipVisitor implements FeatureVisitor {

        /**

         * Clipping geometry: the convex hull of the

         * clipping layer

         */

        private Geometry clippingConvexHull;

        /**

         * It allows visitor to get attribute values link to geometries

         */

        private SelectableDataSource recordset;

        /**

         * Processes individual clip results

         */

        private FeaturePersisterProcessor resultProcessor;

        /**

         * Constructor. It requires clipping geometry.

         * @param clippingGeometry

         */

        public ClipVisitor(Geometry clippingGeometry, 

                                ITableDefinition layerDefinition,

                                ISchemaManager schemaManager,

                                IWriter writer){

                this.clippingConvexHull = clippingGeometry;

                try {

                        this.resultProcessor = new FeaturePersisterProcessor(layerDefinition,

                                        schemaManager,writer);

                } catch (EditionException e) {

                        // TODO Auto-generated catch block

                        e.printStackTrace();

                }

        }

        /**

         * clips feature's geometry with the clipping geometry, preserving

         * feature's original attributes.

         * If feature's geometry doesnt touch clipping geometry, it will be

         * ignored.

         */

        public void visit(IGeometry g, int index) throws VisitException {

                Geometry jtsGeom = g.toJTSGeometry();

                //first of all we check envelopes

                if(!jtsGeom.getEnvelope().intersects(clippingConvexHull.getEnvelope()))

                        return;

                if(jtsGeom.intersects(clippingConvexHull)){

                        Geometry newGeom = jtsGeom.intersection(clippingConvexHull);

                        resultProcessor.processJtsGeometry(newGeom, index);

                }

        }

        public void stop(FLayer layer) {

                resultProcessor.finish();

        }

        public boolean start(FLayer layer) {

                if(layer instanceof AlphanumericData && layer instanceof VectorialData){

                        try {

                                this.recordset = ((AlphanumericData)layer).getRecordset();

                                this.resultProcessor.setSelectableDataSource(recordset);

                        } catch (DriverException e) {

                                return false;//must we throw an Exception??

                        }

                        return true;

                }

                return false;

        }

        public SelectableDataSource getRecordset() {

                return recordset;

        }

        public void setRecordset(SelectableDataSource recordset) {

                this.recordset = recordset;

        }

        public String getProcessDescription() {

                return "Clipping features agaisnt a clip geometry";

        }

}