/* Copyright (c) 2001 - 2007 TOPP - www.openplans.org. All rights reserved.
* This code is licensed under the GPL 2.0 license, availible at the root
* application directory.
*/
package org.vfny.geoserver.wms.responses.map.kml;
import java.sql.Connection;
import java.util.Map;
import org.geoserver.catalog.FeatureTypeInfo;
import org.geoserver.catalog.LayerInfo;
import org.geoserver.config.GeoServer;
import org.geoserver.wms.MapLayerInfo;
import org.geotools.data.DefaultQuery;
import org.geotools.data.FeatureSource;
import org.geotools.factory.CommonFactoryFinder;
import org.geotools.feature.FeatureIterator;
import org.geotools.geometry.jts.ReferencedEnvelope;
import org.geotools.map.MapLayer;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.feature.type.AttributeType;
import org.opengis.feature.type.GeometryDescriptor;
import org.opengis.filter.FilterFactory;
import org.opengis.filter.sort.SortBy;
import org.opengis.filter.sort.SortOrder;
import org.opengis.filter.spatial.BBOX;
import org.vfny.geoserver.wms.WMSMapContext;
import org.vfny.geoserver.wms.WmsException;
/**
* An attribute based regionating strategy assuming it's possible (and fast) to
* sort on the user specified attribute. Features with higher values of the
* attribute will be found in higher tiles.
*
* @author Andrea Aime
*
*/
public class NativeSortRegionatingStrategy extends
CachedHierarchyRegionatingStrategy {
public NativeSortRegionatingStrategy(GeoServer gs) {
super(gs);
}
static final FilterFactory ff = CommonFactoryFinder.getFilterFactory(null);
String attribute;
FeatureSource fs;
@Override
protected String getDatabaseName(WMSMapContext con, MapLayer layer)
throws Exception {
fs = layer.getFeatureSource();
SimpleFeatureType type = (SimpleFeatureType) fs.getSchema();
// find out which attribute we're going to use
Map options = con.getRequest().getFormatOptions();
attribute = (String) options.get("regionateAttr");
if (attribute == null)
attribute = MapLayerInfo.getRegionateAttribute( featureType );
if (attribute == null)
throw new WmsException("Regionating attribute has not been specified");
// Make sure the attribute is actually there
AttributeType attributeType = type.getType(attribute);
if (attributeType == null) {
throw new WmsException("Could not find regionating attribute "
+ attribute + " in layer " + featureType.getName());
}
// check we can actually sort on that attribute
if(!fs.getQueryCapabilities().supportsSorting(new SortBy[] {ff.sort(attribute, SortOrder.DESCENDING)}))
throw new WmsException("Native sorting on the " + attribute
+ " is not possible for layer " + featureType.getName());
// make sure a special db for this layer and attribute will be created
return super.getDatabaseName(con, layer) + "_" + attribute;
}
@Override
protected String getDatabaseName(FeatureTypeInfo cfg) throws Exception {
return super.getDatabaseName(cfg) + "_" + MapLayerInfo.getRegionateAttribute(cfg);
}
public FeatureIterator getSortedFeatures(GeometryDescriptor geom,
ReferencedEnvelope latLongEnv, ReferencedEnvelope nativeEnv,
Connection cacheConn) throws Exception {
// build the bbox filter
FilterFactory ff = CommonFactoryFinder.getFilterFactory(null);
BBOX filter = ff.bbox(geom.getLocalName(), nativeEnv.getMinX(),
nativeEnv.getMinY(), nativeEnv.getMaxX(), nativeEnv.getMaxY(), null);
// build an optimized query (only the necessary attributes
DefaultQuery q = new DefaultQuery();
q.setFilter(filter);
q.setPropertyNames(new String[] { geom.getLocalName(), attribute });
// TODO: enable this when JTS learns how to compute centroids
// without triggering the
// generation of Coordinate[] out of the sequences...
// q.setHints(new Hints(Hints.JTS_COORDINATE_SEQUENCE_FACTORY,
// PackedCoordinateSequenceFactory.class));
q.setSortBy(new SortBy[] { ff.sort(attribute, SortOrder.DESCENDING) });
// return the reader
return fs.getFeatures(q).features();
}
}