/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library 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
* Lesser General Public License for more details.
*/
package org.geotools.swt.tool;
import java.io.IOException;
import java.lang.ref.WeakReference;
import org.geotools.data.Query;
import org.geotools.data.simple.SimpleFeatureCollection;
import org.geotools.factory.CommonFactoryFinder;
import org.geotools.geometry.DirectPosition2D;
import org.geotools.geometry.jts.Geometries;
import org.geotools.geometry.jts.JTS;
import org.geotools.geometry.jts.JTSFactoryFinder;
import org.geotools.geometry.jts.ReferencedEnvelope;
import org.geotools.map.Layer;
import org.geotools.map.MapContent;
import org.opengis.feature.type.GeometryDescriptor;
import org.opengis.filter.Filter;
import org.opengis.filter.FilterFactory2;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
import org.opengis.referencing.operation.MathTransform;
import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.GeometryFactory;
/**
* Helper class used by {@code InfoTool} to query {@code MapLayers}
* with vector feature data.
* <p>
* Implementation note: this class keeps only a weak reference to
* the {@code MapLayer} it is working with to avoid memory leaks if
* the layer is deleted.
*
* @see InfoTool
* @see GridLayerHelper
*
* @author Michael Bedward
* @since 2.6
*
*
* @source $URL$
*/
public class VectorLayerHelper extends InfoToolHelper<SimpleFeatureCollection> {
private static final GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory(null);
private static final FilterFactory2 filterFactory = CommonFactoryFinder.getFilterFactory2(null);
private final WeakReference<Layer> layerRef;
private final String attrName;
private final boolean isPolygonGeometry;
/**
* Create a new helper to work with a {@code MapLayer} that has vector feature data.
*
* @param layer the map layer
*
* @param geomAttributeName the name of the geometry attribute for {@code Features}
*
* @param geomClass the geometry class
*/
@SuppressWarnings("unchecked")
public VectorLayerHelper( MapContent context, Layer layer ) {
super(context, layer.getFeatureSource().getSchema().getCoordinateReferenceSystem());
this.layerRef = new WeakReference<Layer>(layer);
final GeometryDescriptor geomDesc = layer.getFeatureSource().getSchema().getGeometryDescriptor();
this.attrName = geomDesc.getLocalName();
final Class< ? extends Geometry> geomClass = (Class< ? extends Geometry>) geomDesc.getType().getBinding();
final Geometries type = Geometries.getForBinding(geomClass);
this.isPolygonGeometry = (type == Geometries.POLYGON || type == Geometries.MULTIPOLYGON);
}
/**
* {@inheritDoc}
*/
public boolean isValid() {
return getMapContent() != null && layerRef != null && layerRef.get() != null;
}
/**
* Get the {@code MapLayer} that this helper is working with.
*
* @return the {@code MapLayer} or null if the original layer is no longer valid
*
* @see #isValid()
*/
public Layer getMapLayer() {
return layerRef != null ? layerRef.get() : null;
}
/*
* Get feature data at the given position.
*
* @param pos the location to query
*
*
*/
/**
* {@inheritDoc}
*
* @param params a {@code Double} value for the search radius to use with
* point or line features
*
* @return the features that lie within the search radius of {@code pos}; if
* this helper is not valid an empty collection will be returned
*
* @throws IOException if the feature source for the layer cannot be accessed
*/
public SimpleFeatureCollection getInfo( DirectPosition2D pos, Object... params ) throws IOException {
SimpleFeatureCollection collection = null;
Layer layer = layerRef.get();
if (layer != null) {
Filter filter = null;
if (isPolygonGeometry) {
/*
* Polygon features - use an intersects filter
*/
Geometry posGeom = createSearchPos(pos);
filter = filterFactory.intersects(filterFactory.property(attrName), filterFactory.literal(posGeom));
} else {
/*
* Line or point features - use a bounding box filter
*/
double radius = ((Number) params[0]).doubleValue();
ReferencedEnvelope env = createSearchEnv(pos, radius);
filter = filterFactory.bbox(filterFactory.property(attrName), env);
}
Query query = new Query(null, filter);
query.setCoordinateSystemReproject(getMapContent().getCoordinateReferenceSystem());
collection = (SimpleFeatureCollection) layer.getFeatureSource().getFeatures(query);
}
return collection;
}
private Geometry createSearchPos( DirectPosition2D pos ) {
Geometry point = geometryFactory.createPoint(new Coordinate(pos.x, pos.y));
if (isTransformRequired()) {
MathTransform transform = getTransform();
if (transform != null) {
try {
point = JTS.transform(point, transform);
} catch (Exception ex) {
throw new IllegalStateException(ex);
}
}
}
return point;
}
private ReferencedEnvelope createSearchEnv( DirectPosition2D pos, double radius ) {
final CoordinateReferenceSystem contextCRS = getMapContent().getCoordinateReferenceSystem();
ReferencedEnvelope env = new ReferencedEnvelope(pos.x - radius, pos.x + radius, pos.y - radius, pos.y + radius,
contextCRS);
if (isTransformRequired()) {
CoordinateReferenceSystem layerCRS = layerRef.get().getFeatureSource().getSchema().getCoordinateReferenceSystem();
try {
env = env.transform(layerCRS, true);
} catch (Exception ex) {
throw new IllegalStateException(ex);
}
}
return env;
}
}