| gvSIG desktop 1

/*

 * Created on 12-abr-2007

 *

 * 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: AttrQueryFeatureIterator.java 33330 2010-08-24 09:12:44Z vcaballero $

 * $Log$

 * Revision 1.1  2007-05-29 19:08:11  azabala

 * first version in cvs

 *

 * Revision 1.1  2007/04/19 17:27:58  azabala

 * first version in cvs

 *

 *

 */

package com.iver.cit.gvsig.fmap.drivers.featureiterators;

import org.cresques.cts.IProjection;

import com.hardcode.gdbms.driver.exceptions.ReadDriverException;

import com.hardcode.gdbms.engine.data.DataSource;

import com.hardcode.gdbms.engine.data.DataSourceFactory;

import com.hardcode.gdbms.engine.values.Value;

import com.iver.cit.gvsig.exceptions.expansionfile.ExpansionFileReadException;

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

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

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

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

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

/**

 * Iterates over the features of a vectorial data source

 * (readablevectorial, or vectorialadapter) which verify a SQL statement.

 * <br>

 * SQL syntax is very extrict, GDBMS based.

 * (for example, % character is not allowed to build strings expressions,

 * all SQL statement must end with ;, etc)

 *

 *

 *

 *

 * @author azabala

 *

 */

public class AttrQueryFeatureIterator extends DefaultFeatureIterator {

        private String sqlQuery;

        private long[] indexes;

        public AttrQueryFeatureIterator(ReadableVectorial source,

                        IProjection sourceProj,

                        IProjection targetProj,

                        String sqlQuery) throws ReadDriverException {

                super(source,sourceProj,targetProj,source.getRecordset().getFieldNames());

                this.sqlQuery = sqlQuery;

                try {

                        if(hasWhere(sqlQuery)){

                                DataSource datasource = LayerFactory.getDataSourceFactory().executeSQL(sqlQuery,

                                                DataSourceFactory.MANUAL_OPENING);

                                super.setFieldNames(source.getRecordset().getFieldNames());

                                indexes = datasource.getWhereFilter();

                        }else{

                                //TODO This is not very elegant: rethink

                                indexes = new long[source.getShapeCount()];

                                for(int i = 0; i < indexes.length; i++){

                                        indexes[i] = i;

                                }

                                super.setFieldNames(source.getRecordset().getFieldNames());

                        }

                        //check to avoid reprojections with the same projection

                        if(targetProj != null){

                                // FJP: Si la capa original no sabemos que proyeccion tiene, no hacemos nada

                                if (sourceProj != null) {

                                        if(!(targetProj.getAbrev().equalsIgnoreCase(sourceProj.getAbrev())))

                                                this.targetProjection = targetProj;

                                }

                        }

                } catch (Exception e){

                        throw new ReadDriverException("error ejecutando consulta sql para iterador", e);

                }

        }

        public boolean hasNext(){

                if(indexes != null && currentFeature < indexes.length)

                        return true;

                else

                        return false;

        }

        private boolean hasWhere(String expression) {

                String subExpression = expression.trim();

                int pos;

                // Remove last ';' if exists

                if (subExpression.charAt(subExpression.length() -1) == ';')

                        subExpression = subExpression.substring(0, subExpression.length() -1).trim();

                // If there is no 'where' clause

                if ((pos = subExpression.indexOf("where")) == -1)

                        return false;

                // If there is no subexpression in the WHERE clause -> true

                subExpression = subExpression.substring(pos + 5, subExpression.length()).trim(); // + 5 is the length of 'where'

                if ( subExpression.length() == 0 )

                        return false;

                else

                        return true;

        }

        public IFeature next() throws ReadDriverException {

                IGeometry geom;

                try {

                        geom = chekIfCloned(source.getShape((int)indexes[currentFeature]));

                        reprojectIfNecessary(geom);

                } catch (ExpansionFileReadException e) {

                        throw new ReadDriverException("Error accediendo al driver", e);

                }

                Value[] regAtt = getValues((int)indexes[currentFeature]);

                DefaultFeature feat = new DefaultFeature(geom, regAtt, (int)indexes[currentFeature] + "");

                currentFeature++;

                return feat;

        }

        public String getSqlQuery() {

                return sqlQuery;

        }

}