PrecisionToolsUtil.java

/* Spatial Operations & Editing Tools for uDig
 * 
 * Axios Engineering under a funding contract with: 
 *      Diputación Foral de Gipuzkoa, Ordenación Territorial 
 *
 *      http://b5m.gipuzkoa.net
 *      http://www.axios.es 
 *
 * (C) 2006, Diputación Foral de Gipuzkoa, Ordenación Territorial (DFG-OT). 
 * DFG-OT agrees to licence under Lesser General Public License (LGPL).
 * 
 * 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 es.axios.udig.ui.editingtools.precisiontools.commons.internal;

import java.io.IOException;

import net.refractions.udig.project.ILayer;
import net.refractions.udig.project.internal.ProjectPlugin;
import net.refractions.udig.project.ui.render.displayAdapter.MapMouseEvent;
import net.refractions.udig.tools.edit.EditToolHandler;
import net.refractions.udig.tools.edit.preferences.PreferenceUtil;
import net.refractions.udig.tools.edit.support.SnapBehaviour;

import org.geotools.data.FeatureSource;
import org.geotools.data.FeatureStore;
import org.geotools.factory.CommonFactoryFinder;
import org.geotools.factory.GeoTools;
import org.geotools.feature.FeatureCollection;
import org.geotools.feature.FeatureIterator;
import org.geotools.geometry.jts.ReferencedEnvelope;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.feature.type.GeometryDescriptor;
import org.opengis.feature.type.Name;
import org.opengis.filter.Filter;
import org.opengis.filter.FilterFactory2;
import org.opengis.filter.spatial.BBOX;
import org.opengis.referencing.FactoryException;
import org.opengis.referencing.operation.TransformException;

/**
 * Utility class.
 * 
 * @author Aritz Davila (www.axios.es)
 * @author Mauricio Pazos (www.axios.es)
 */
public class PrecisionToolsUtil {

	private PrecisionToolsUtil() {

		// utility class pattern
	}

	/**
	 * Search if there is a feature under cursor position. If snap is off,
	 * search on a little bbox around cursor, if it's on, search around an
	 * accurate bbox similar to the snap area.
	 * 
	 * @return True if its a feature under the cursor position, false otherwise.
	 */
	public static boolean isFeatureUnderCursor(EditToolHandler handler, MapMouseEvent e) {

		int snapRadious = 5;
		// if snap is on, set an accurate snapRadious to use later for
		// getting
		// its area.
		if (PreferenceUtil.instance().getSnapBehaviour() != SnapBehaviour.OFF) {
			snapRadious = PreferenceUtil.instance().getSnappingRadius()
						+ (PreferenceUtil.instance().getSnappingRadius() / 2);
		}

		// transforms the bbox to the layer crs
		ReferencedEnvelope bbox = handler.getContext().getBoundingBox(e.getPoint(), snapRadious);
		try {
			bbox = bbox.transform(handler.getEditLayer().getCRS(), true);
		} catch (TransformException te) {
			te.printStackTrace();
		} catch (FactoryException fe) {
			fe.printStackTrace();
		}

		FeatureCollection<SimpleFeatureType, SimpleFeature> collection = null;
		FeatureIterator<SimpleFeature> iterator = null;

		try {
			Class<? extends Filter> filterType = BBOX.class;
			FeatureStore<SimpleFeatureType, SimpleFeature> store = handler.getEditLayer().getResource(
						FeatureStore.class, null);
			Filter createBBoxFilter = createBBoxFilter(bbox, handler.getEditLayer(), filterType);
			collection = store.getFeatures(createBBoxFilter);
			iterator = collection.features();
			if (iterator.hasNext()) {
				return true;
			}
		} catch (IOException e1) {
			e1.printStackTrace();
		} finally {
			if (iterator != null) {
				collection.close(iterator);
			}
		}
		return false;
	}

	/**
	 * Creates A geometry filter for the given layer.
	 * 
	 * @param boundingBox
	 *            in the same crs as the viewport model.
	 * @return a Geometry filter in the correct CRS or null if an exception
	 *         occurs.
	 */
	private static Filter createBBoxFilter(	ReferencedEnvelope boundingBox,
											ILayer layer,
											Class<? extends Filter> filterType) {
		FilterFactory2 factory = CommonFactoryFinder.getFilterFactory2(GeoTools.getDefaultHints());
		if (!layer.hasResource(FeatureSource.class))
			return Filter.EXCLUDE;
		try {

			SimpleFeatureType schema = layer.getSchema();
			Name geom = getGeometryAttDescriptor(schema).getName();

			Filter bboxFilter = factory.bbox(factory.property(geom), boundingBox);

			return bboxFilter;
		} catch (Exception e) {
			ProjectPlugin.getPlugin().log(e);
			return Filter.EXCLUDE;
		}
	}

	private static GeometryDescriptor getGeometryAttDescriptor(SimpleFeatureType schema) {
		return schema.getGeometryDescriptor();
	}

	/**
	 * Get the feature under the cursor, the first one if there are more than
	 * one. Return null if there isn't feature under the cursor. TODO improve
	 * the case when there are more than 1 feature under the cursor.
	 * 
	 * @param handler
	 * @param e
	 * @return
	 */
	public static SimpleFeature getFeatureUnderCursor(EditToolHandler handler, MapMouseEvent e) {

		int snapRadious = 5;
		// if snap is on, set an accurate snapRadious to use later for
		// getting
		// its area.
		if (PreferenceUtil.instance().getSnapBehaviour() != SnapBehaviour.OFF) {
			snapRadious = PreferenceUtil.instance().getSnappingRadius()
						+ (PreferenceUtil.instance().getSnappingRadius() / 2);
		}

		// transforms the bbox to the layer crs
		ReferencedEnvelope bbox = handler.getContext().getBoundingBox(e.getPoint(), snapRadious);
		try {
			bbox = bbox.transform(handler.getEditLayer().getCRS(), true);
		} catch (TransformException te) {
			te.printStackTrace();
		} catch (FactoryException fe) {
			fe.printStackTrace();
		}

		FeatureCollection<SimpleFeatureType, SimpleFeature> collection = null;
		FeatureIterator<SimpleFeature> iterator = null;

		try {
			Class<? extends Filter> filterType = BBOX.class;
			FeatureStore<SimpleFeatureType, SimpleFeature> store = handler.getEditLayer().getResource(
						FeatureStore.class, null);
			Filter createBBoxFilter = createBBoxFilter(bbox, handler.getEditLayer(), filterType);
			collection = store.getFeatures(createBBoxFilter);
			iterator = collection.features();
			if (iterator.hasNext()) {
				return iterator.next();
			}
		} catch (IOException e1) {
			e1.printStackTrace();
		} finally {
			if (iterator != null) {
				collection.close(iterator);
			}
		}

		return null;
	}
}