/*
* 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.data.store;
import java.util.Iterator;
import org.geotools.feature.IllegalAttributeException;
import org.geotools.feature.simple.SimpleFeatureBuilder;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.feature.type.AttributeDescriptor;
/**
* Iterator wrapper which re-types features on the fly based on a target
* feature type.
*
* @author Justin Deoliveira, The Open Planning Project
*
*
* @source $URL$
*/
public class ReTypingIterator implements Iterator {
/**
* The delegate iterator
*/
Iterator delegate;
/**
* The target feature type
*/
SimpleFeatureType target;
/**
* The matching types from target
*/
AttributeDescriptor[] types;
SimpleFeatureBuilder builder;
public ReTypingIterator( Iterator delegate, SimpleFeatureType source, SimpleFeatureType target ) {
this.delegate = delegate;
this.target = target;
types = typeAttributes( source, target );
this.builder = new SimpleFeatureBuilder(target);
}
public Iterator getDelegate() {
return delegate;
}
public void remove() {
delegate.remove();
}
public boolean hasNext() {
return delegate.hasNext();
}
public Object next() {
SimpleFeature next = (SimpleFeature) delegate.next();
String id = next.getID();
try {
for (int i = 0; i < types.length; i++) {
final String xpath = types[i].getLocalName();
builder.add(next.getAttribute(xpath));
}
return builder.buildFeature(id);
}
catch (IllegalAttributeException e) {
throw new RuntimeException( e );
}
}
/**
* Supplies mapping from origional to target FeatureType.
*
* <p>
* Will also ensure that origional can cover target
* </p>
*
* @param target Desired FeatureType
* @param origional Origional FeatureType
*
* @return Mapping from originoal to target FeatureType
*
* @throws IllegalArgumentException if unable to provide a mapping
*/
protected AttributeDescriptor[] typeAttributes(SimpleFeatureType original,
SimpleFeatureType target) {
if (target.equals(original)) {
throw new IllegalArgumentException(
"FeatureReader allready produces contents with the correct schema");
}
if (target.getAttributeCount() > original.getAttributeCount()) {
throw new IllegalArgumentException(
"Unable to retype FeatureReader<SimpleFeatureType, SimpleFeature> (origional does not cover requested type)");
}
String xpath;
AttributeDescriptor[] types = new AttributeDescriptor[target.getAttributeCount()];
for (int i = 0; i < target.getAttributeCount(); i++) {
AttributeDescriptor attrib = target.getDescriptor(i);
xpath = attrib.getLocalName();
types[i] = attrib;
if (!attrib.equals(original.getDescriptor(xpath))) {
throw new IllegalArgumentException(
"Unable to retype FeatureReader<SimpleFeatureType, SimpleFeature> (origional does not cover "
+ xpath + ")");
}
}
return types;
}
}