/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2004-2008, 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.store;
import java.io.IOException;
import java.util.Iterator;
import java.util.NoSuchElementException;
import org.geotools.data.FeatureWriter;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
/**
* An iterator wrapper for a FeatureWriter - for use with
* an AbstractFeatureCollection.
* <p>
* There is no reason modify this class, subclasses that wish
* to work with a custom iterator need just that - a custom iterator.
* <p>
* <p>
* The use of this class against a SimpleFeatureSource not backed by
* a Transaction may *really* cut into performance. Consider if
* you will the overhead involved in writing out each feature into
* a temporary file (when the user may not even modify anything).
* </p>
* @author jgarnett
* @since 2.1.RC0
* @source $URL$
*/
final class FeatureWriterIterator implements Iterator<SimpleFeature> {
FeatureWriter<SimpleFeatureType, SimpleFeature> writer;
public FeatureWriterIterator( FeatureWriter<SimpleFeatureType, SimpleFeature> writer ){
this.writer = writer;
}
public boolean hasNext() {
try {
if( writer == null ) {
return false;
}
writer.write(); // write out any "changes" made
if( writer.hasNext() ){
return true;
}
else {
close();
return false;
// auto close because we don't trust client
// code to call close
}
} catch (IOException e) {
close();
return false; // failure sounds like lack of next to me
}
}
public SimpleFeature next() {
if( writer == null ) {
throw new NoSuchElementException( "Iterator has been closed" );
}
try {
return writer.next();
} catch (IOException io) {
NoSuchElementException problem = new NoSuchElementException( "Could not obtain the next feature:"+io );
problem.initCause( io );
throw problem;
}
}
public void remove() {
try {
writer.remove();
} catch (IOException problem) {
throw (IllegalStateException) new IllegalStateException( "Could not remove feature" ).initCause( problem );
}
}
/**
* This method only needs package visability as only AbstractFeatureCollection
* is trusted enough to call it.
*/
void close(){
if( writer != null){
try {
writer.close();
} catch (IOException e) {
// sorry but iterators die quitely in the night
}
writer = null;
}
}
};