Metacat

/**

 *  '$RCSfile$'

 *  Copyright: 2000 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *

 * Author: Matthew Perry 

 * '$Date$'

 * '$Revision$'

 *

 * 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

 */

package edu.ucsb.nceas.metacat.spatial;

import org.geotools.feature.FeatureType;

import org.geotools.data.shapefile.ShapefileDataStore;

import org.geotools.data.FeatureStore;

import org.geotools.data.FeatureSource;

import org.geotools.data.DefaultTransaction;

import org.geotools.data.Transaction;

import org.geotools.feature.Feature;

import org.geotools.filter.Filter;

import org.geotools.filter.AbstractFilter;

import org.geotools.filter.Expression;

import org.geotools.filter.CompareFilter;

import org.geotools.filter.GeometryFilter;

import org.geotools.filter.FilterFactory;

import org.geotools.filter.FilterFactoryFinder;

import org.geotools.filter.IllegalFilterException;

import org.geotools.feature.FeatureCollection;

import org.geotools.feature.FeatureCollections;

import com.vividsolutions.jts.geom.Envelope;

import java.io.File;

import java.net.URI;

import java.net.URL;

import java.net.MalformedURLException;

import java.sql.ResultSet;

import java.sql.PreparedStatement;

import java.util.Vector;

import java.util.Iterator; 

import java.io.IOException;

import org.apache.log4j.Logger;

import edu.ucsb.nceas.metacat.MetaCatUtil;

/** 

 * Class to query the persistent spatial cache

 * and returns docids matching spatial constraints

 */

public class SpatialQuery {

  private static Logger log = Logger.getLogger(SpatialQuery.class.getName());

  /** 

   * empty constructor to initialize spatial query

   */

  public SpatialQuery() { }

  /**

   * Querys all features in the spatial cache 

   * and filters based on bouding coordinates.

   * Returns Vector of docids.

   *

   * @param w West bounding coordinate 

   * @param s South bounding coordinate 

   * @param e East bounding coordinate 

   * @param n North bounding coordinate 

   *

   */

  public Vector filterByBbox( Float w, Float s, Float e, Float n ) {

      Vector docids = new Vector();

      SpatialFeatureSchema featureSchema = new SpatialFeatureSchema();

      // MPTDO, perform geotools spatial query

      // test

      docids.add("test1.1");

      docids.add("test2.1");

      ShapefileDataStore store = null;

      FeatureSource features = null;

      FeatureCollection collection = null;

      FilterFactory filterFactory = FilterFactoryFinder.createFilterFactory();

      try {

          store = new ShapefileDataStore( (new File( featureSchema.polygonShpUri )).toURL() );

          features = store.getFeatureSource(store.getTypeNames()[0]);

          //count features

          //col = features.getFeatures();

          //System.out.println("# cities (no filter)= "+col.size());

          Envelope envelope = new Envelope( w, e, s, n ); 

          Expression bbox = filterFactory.createBBoxExpression( envelope );

          FeatureType featureType = store.getSchema( store.getTypeNames()[0] );

          Expression geometry = filterFactory.createAttributeExpression( featureType.getDefaultGeometry().getName()  );

          GeometryFilter bboxFilter = filterFactory.createGeometryFilter(AbstractFilter.GEOMETRY_BBOX);

          bboxFilter.addLeftGeometry( geometry );

          bboxFilter.addRightGeometry( bbox );

          //count filtered features

          collection = features.getFeatures(bboxFilter);

          //System.out.println("# cities (after filter)= "+col.size());

          Iterator iterator = collection.iterator();

          try {

              for( Iterator i=collection.iterator(); i.hasNext(); ) {

                  Feature feature = (Feature) i.next();

                  docids.add( (String) feature.getAttribute(1) );

              }

          } finally {

              collection.close( iterator );

          }

        } catch (MalformedURLException ex) {

            ex.printStackTrace();

        } catch (IOException ex) {

            ex.printStackTrace();

        } catch (IllegalFilterException ex) {

            ex.printStackTrace();

        }

      return docids;

  }

}

import edu.ucsb.nceas.metacat.spatial.SpatialQuery;

        Logger logMetacat = Logger.getLogger(MetaCatServlet.class);

        /* 

         * Perform spatial query against spatial cache

         */

        Float _xmax = Float.parseFloat( ((String[]) params.get("XMAX"))[0] );

        Float _ymax = Float.parseFloat( ((String[]) params.get("YMAX"))[0] );

        Float _xmin = Float.parseFloat( ((String[]) params.get("XMIN"))[0] );

        Float _ymin = Float.parseFloat( ((String[]) params.get("YMIN"))[0] );

        SpatialQuery sq = new SpatialQuery();

        Vector docids = sq.filterByBbox( _xmin, _ymin, _xmax, _ymax );

        logMetacat.info(" --- Spatial Query completed. Passing on the SQuery handler");

        /*

         * Create an squery based on vector of matching docids

         */

        String [] docidArray = new String[docids.size()];

        docids.toArray(docidArray);

        String squery = DocumentIdQuery.createDocidQuery( docidArray );

        /*

         * Pass to squery handler

         */

        String[] queryArray = new String[1];

        queryArray[0] = squery;

        params.put("query", queryArray);

        // qformat

        String[] qformatArray = new String[1];

        try {

            String _skin = ((String[]) params.get("SKIN"))[0];

            qformatArray[0] = _skin;

        } catch (java.lang.NullPointerException e) {

            // should be "default" but keep this for backwards compatibility with knp site

            logMetacat.warn("No SKIN specified for metacat actions=spatial_query... defaulting to 'knp' skin !\n");

            qformatArray[0] = "knp";

        }

        params.put("qformat", qformatArray);

        // change the action

        String[] actionArray = new String[1];

        actionArray[0] = "squery";

        params.put("action", actionArray);

        handleSQuery(out, params, response, username, groupnames, sess_id);

  }