Filtered SimpleFeatureCollection really slow on Map and other operations

Question

I'm working with a shapefile having about 85.000 features. I need to select some of these using a filter and then showing these on a map. Now... If I draw the entire shapefile's features the creation of the map, the zooming and moving around is fast but if I select, even only 100, features from the SimpleFeatureSource, these steps are really slow. Here is how I select, for example, the first 1000 features and then draw:

The execution stuks at Layer layer = new FeatureLayer (features, style);

and at JMapFrame.showMap(map);

public static void main(String[] args) {
    File file = JFileDataStoreChooser.showOpenFile("shp", null);
     if (file == null) return;
 try{

        FileDataStore store = FileDataStoreFinder.getDataStore(file);
        SimpleFeatureSource featureSource = store.getFeatureSource();

        FilterFactory2 ff = CommonFactoryFinder.getFilterFactory2();

        String[] selection = new String[1000];

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

            selection[i] = i+"";

        }

        ArrayList<Filter> match = new ArrayList<Filter>();

        for (String name : selection) {
            Filter aMatch = ff.equal(ff.property("ID"), ff.literal(name), false);
            match.add(aMatch);
        }
        Filter filter = ff.or(match);

        SimpleFeatureCollection features = featureSource.getFeatures(filter);



        // Create a map content and add our shapefile to it
        MapContent map = new MapContent();
        map.setTitle("Quickstart");


        Style style = SLD.createSimpleStyle(features.getSchema());


        Layer layer = new FeatureLayer(features, style);

        map.addLayer(layer);

        // Now display the map
        JMapFrame.showMap(map);

        }catch (Exception e)
        {
            e.printStackTrace();
}

Are there some faster way to do this? ......

Answer 1

There are two ways to speed up drawing a layer in GeoTools, first speed up reading the file and second only read it once.

In the first case you should consider moving your data to a database and accessing that through the relevant datastore - otherwise the code will be identical.

In the second case you can read all of the features into memory and wrap them in an SpatialIndexFeatureCollection.

SpatialIndexFeatureCollection indexed = new SpatialIndexFeatureCollection((SimpleFeatureType) source.getFeatures());

Which will speed up spatial searches.