/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2007-2008, 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.data.ogr;
import java.io.IOException;
import java.util.NoSuchElementException;
import org.gdal.ogr.DataSource;
import org.gdal.ogr.Layer;
import org.geotools.data.FeatureReader;
import org.geotools.feature.Feature;
import org.geotools.feature.FeatureType;
import org.geotools.feature.IllegalAttributeException;
import com.vividsolutions.jts.geom.GeometryFactory;
/**
* An OGR feature reader, reads data from the provided layer.<br>
* It assumes eventual filters have already been set on it, and will extract
* only the
*
* @author aaime
*
* @source $URL$
*/
public class OGRFeatureReader implements FeatureReader {
DataSource ds;
Layer layer;
FeatureType schema;
org.gdal.ogr.Feature curr;
private FeatureMapper mapper;
boolean layerCompleted;
public OGRFeatureReader(DataSource ds, Layer layer, FeatureType schema) {
this.ds = ds;
this.layer = layer;
this.schema = schema;
this.layer.ResetReading();
this.layerCompleted = false;
// TODO: use the most appropriate Geometry Factory once the SPI system
// allows us to provide such an hint
this.mapper = new FeatureMapper(new GeometryFactory());
}
public void close() throws IOException {
if (curr != null) {
curr.delete();
curr = null;
}
if (layer != null) {
layer.delete();
layer = null;
}
if (ds != null) {
ds.delete();
ds = null;
}
schema = null;
}
protected void finalize() throws Throwable {
close();
}
public FeatureType getFeatureType() {
return schema;
}
public boolean hasNext() throws IOException {
// ugly, but necessary to close the reader when getting to the end, because
// it would break feature appending otherwise (the reader is used in feature
// writing too)
if(layerCompleted)
return false;
if (curr != null)
return true;
boolean hasNext = (curr = layer.GetNextFeature()) != null;
if(!hasNext)
layerCompleted = true;
return hasNext;
}
public Feature next() throws IOException, IllegalAttributeException, NoSuchElementException {
if (!hasNext())
throw new NoSuchElementException("There are no more Features to be read");
Feature f = mapper.convertOgrFeature(schema, curr);
// .. nullify curr, so that we can move to the next one
curr.delete();
curr = null;
return f;
}
}