WfsTask.java - geometry layer sample task

WfsTask.java

package com.nutiteq.app.layers;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.LinkedList;
import java.util.List;
import java.util.Vector;
import java.util.concurrent.locks.ReentrantLock;

import javax.xml.parsers.ParserConfigurationException;

import org.xml.sax.SAXException;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlPullParserFactory;

import com.nutiteq.components.ImmutableMapPos;
import com.nutiteq.components.MapPos;
import com.nutiteq.geometry.Geometry;
import com.nutiteq.geometry.Line;
import com.nutiteq.geometry.Polygon;
import com.nutiteq.log.Log;
import com.nutiteq.projections.Projection;
import com.nutiteq.style.LineStyle;
import com.nutiteq.style.PointStyle;
import com.nutiteq.style.PolygonStyle;
import com.nutiteq.style.StyleSet;
import com.nutiteq.tasks.Task;
import com.nutiteq.ui.DefaultLabel;
import com.nutiteq.vectorlayers.GeometryLayer;
import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.Envelope;
import com.vividsolutions.jts.geom.GeometryCollection;
import com.vividsolutions.jts.geom.LineString;
import com.vividsolutions.jts.geom.MultiLineString;
import com.vividsolutions.jts.geom.MultiPolygon;
import com.vividsolutions.jts.geom.Point;
import com.vividsolutions.jts.io.gml2.GMLReader;

// NB! This parses currently only Point elements, but it would be quite easy to extend it to lines and polygons

public class WfsTask implements Task {

    private final GeometryLayer geoLayer;

    private final ReentrantLock modifyLock;

    private final Envelope envelope;

    private final int zoom;

    private Projection projection;
    
    private StyleSet<PointStyle> pointStyleSet;
    private StyleSet<LineStyle> lineStyleSet;
    private StyleSet<PolygonStyle> polygonStyle;

    private String url;

    private Projection dataProjection;

    public WfsTask(Projection projection, String url, Projection dataProjection, GeometryLayer geoLayer,
            ReentrantLock modifyLock, Envelope envelope, int zoom, StyleSet<PointStyle> pointStyleSet,
            StyleSet<LineStyle> lineStyleSet,
            StyleSet<PolygonStyle> polygonStyle) {
        this.geoLayer = geoLayer;
        this.modifyLock = modifyLock;
        this.envelope = envelope;
        this.zoom = zoom;
        this.projection = projection;
        this.dataProjection = dataProjection;
        this.url = url;
        this.pointStyleSet = pointStyleSet;
        this.lineStyleSet = lineStyleSet;
        this.polygonStyle = polygonStyle;
    }

    @Override
    public void run() {
        modifyLock.lock();
        List<Geometry> newVisibleElementsList = downloadGeometries();
        modifyLock.unlock();

        Log.debug("adding elements N="+newVisibleElementsList.size());
        geoLayer.setVisibleElementsList(newVisibleElementsList);
    }

    private List<Geometry> downloadGeometries() {
        Log.debug("download geometries for envelope "+envelope+" zoom "+zoom);
        MapPos bottomLeft = projection.fromInternal((float) envelope.getMinX(), (float) envelope.getMinY());
        MapPos topRight = projection.fromInternal((float) envelope.getMaxX(), (float) envelope.getMaxY());
        Log.debug("bottomLeft "+projection.toWgs84(bottomLeft.x,bottomLeft.y)+" topRight "+projection.toWgs84(topRight.x,topRight.y));

        // convert internal projection->wgs84->dataProjection
        String bbox = ""+
                dataProjection.fromWgs84(
                        projection.toWgs84(bottomLeft.x,bottomLeft.y).x,
                        projection.toWgs84(bottomLeft.x,bottomLeft.y).y).x+
                        ","+
              dataProjection.fromWgs84(projection.toWgs84(bottomLeft.x,bottomLeft.y).x,projection.toWgs84(bottomLeft.x,bottomLeft.y).y).y+
              ","+
              dataProjection.fromWgs84(projection.toWgs84(topRight.x,topRight.y).x,projection.toWgs84(topRight.x,topRight.y).y).x+
              ","+
              dataProjection.fromWgs84(projection.toWgs84(topRight.x,topRight.y).x,projection.toWgs84(topRight.x,topRight.y).y).y; 
        
        List<Geometry> newVisibleElementsList = new LinkedList<Geometry>();

        HttpURLConnection con = null;
        String path = url+"&BBOX="+bbox; 
        URL url;
        InputStream is = null;
        try {
            
            url = new URL(path);
            con = (HttpURLConnection) url.openConnection();
            con.setReadTimeout(10000 /* milliseconds */);
            con.setConnectTimeout(15000 /* milliseconds */);
            con.setRequestMethod("GET");
            con.setDoInput(true);
            // Start the GET query
            con.connect();
            Log.debug("connected "+path);
            is = con.getInputStream();
            BufferedReader reader = new BufferedReader(
                    new InputStreamReader(is));

            String txt = null;
            String year = null;
            String cover = null;
            float x = 0;
            float y = 0;
            
            XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
            factory.setNamespaceAware(false);
            XmlPullParser xpp = factory.newPullParser();
            xpp.setInput(reader);
            int eventType = xpp.getEventType();
            
            while (eventType != XmlPullParser.END_DOCUMENT) {
                switch(eventType){
                case XmlPullParser.START_DOCUMENT:
                    Log.debug("Start XML");
                    break;
  
                case XmlPullParser.END_DOCUMENT:
                    Log.debug("End XML");
                    break;
                    
                case XmlPullParser.START_TAG:
                 //   Log.debug("Start tag "+xpp.getName());
                    // get tag name
                    String tagName = xpp.getName();
                    if(tagName.equals("gml:coordinates")){
                        String coords = xpp.nextText();
                        Log.debug("coordinates in tag: "+coords);
                        String[] cp = coords.split(",");
                        x = Float.valueOf(cp[0]);
                        y = Float.valueOf(cp[1]);
                    }

                    break;
                case XmlPullParser.END_TAG:
                    String name = xpp.getName();
                    Log.debug("End tag "+name);
                    
                    // some schema-specific tags for labels
                    if(name.equals("tvesi:YEAR")){
                        year = txt;
                    }
                    if(name.equals("tvesi:COVERTYPE")){
                        cover = txt;
                    }
                    if(name.equals("gml:featureMember")){
                        DefaultLabel label = new DefaultLabel("COVERTYPE:"+cover,"YEAR:"+year);
                        com.nutiteq.geometry.Point point = new com.nutiteq.geometry.Point(new ImmutableMapPos((float) x, (float) y),
                                label, pointStyleSet, null);
                            point.calculateInternalPos(dataProjection);
                            point.setActiveStyle(zoom);
                            newVisibleElementsList.add(point);
                    }
                    break;
                case XmlPullParser.TEXT:
                    txt = xpp.getText();
                                        
                    break;
                }
                eventType = xpp.next();
            }
             
            
        } catch (IOException ex) {
            Log.error(ex.getMessage());
        } catch (XmlPullParserException e) {
            Log.error(e.getMessage());
            e.printStackTrace();
        } finally {
            try {
                if(is != null)
                    is.close();
            } catch (IOException e) {
                Log.error(e.getMessage());
            }
        }

        return newVisibleElementsList;
    }
    @Override
    public boolean isCancelable() {
        return true;
    }

}