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The main module contains the GeoTools public interfaces that are used by other GeoTools modules (and GeoTools applications). Where possible we make use industry standard terms as provided by OGC and ISO standards. The formal GeoTools public api consists of gt-metadata, jts and the gt-main module. The main module contains the default implementations that are available provided to other GeoTools modules using our factory system. Factories are obtained from an appropriate FactoryFinder, giving applications a chance configure the factory used using the Factory Hints facilities. FilterFactory ff = CommonFactoryFinder.getFilterFactory(); Expression expr = ff.add( expression1, expression2 ); If you find yourself using implementation specific classes chances are you doing it wrong: Expression expr = new AddImpl( expression1, expressiom2 );

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/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2003-2008, 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.crs;

import java.util.Iterator;
import java.util.NoSuchElementException;
import org.geotools.data.simple.SimpleFeatureIterator;
import org.geotools.feature.FeatureIterator;
import org.geotools.feature.simple.SimpleFeatureBuilder;
import org.geotools.geometry.jts.GeometryCoordinateSequenceTransformer;
import org.locationtech.jts.geom.Geometry;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.referencing.operation.MathTransform;
import org.opengis.referencing.operation.TransformException;

/**
 * ReprojectFeatureReader provides a reprojection for FeatureTypes.
 *
 * ReprojectFeatureReader is a wrapper used to reproject GeometryAttributes to a user supplied
 * CoordinateReferenceSystem from the original CoordinateReferenceSystem supplied by the original
 * FeatureReader.
 *
 * 
Example Use:
 *
 * 

 * ReprojectFeatureReader reader =
 *     new ReprojectFeatureReader( originalReader, reprojectCS );
 *
 * CoordinateReferenceSystem originalCS =
 *     originalReader.getFeatureType().getDefaultGeometry().getCoordinateSystem();
 *
 * CoordinateReferenceSystem newCS =
 *     reader.getFeatureType().getDefaultGeometry().getCoordinateSystem();
 *
 * assertEquals( reprojectCS, newCS );
 * 
 *
 * TODO: handle the case where there is more than one geometry and the other geometries have a
 * different CS than the default geometry
 *
 * @author jgarnett, Refractions Research, Inc.
 * @author aaime
 * @author $Author: jive $ (last modification)
 * @version $Id$
 */
public class ReprojectFeatureIterator implements Iterator, SimpleFeatureIterator {
    FeatureIterator reader;
    SimpleFeatureType schema;
    GeometryCoordinateSequenceTransformer transformer = new GeometryCoordinateSequenceTransformer();

    public ReprojectFeatureIterator(
            FeatureIterator reader,
            SimpleFeatureType schema,
            MathTransform transform) {
        this.reader = reader;
        this.schema = schema;
        transformer.setMathTransform(transform);

        // set hte target coordinate system
        transformer.setCoordinateReferenceSystem(schema.getCoordinateReferenceSystem());
    }

    /**
     * Implement getFeatureType.
     *
     * Description ...
     *
     * @see org.geotools.data.FeatureReader#getFeatureType()
     */
    public SimpleFeatureType getFeatureType() {
        if (schema == null) {
            throw new IllegalStateException("Reader has already been closed");
        }

        return schema;
    }

    /**
     * Implement next.
     *
     * 
Description ...
     *
     * @see org.geotools.data.FeatureReader#next()
     */
    public SimpleFeature next() throws NoSuchElementException {
        if (reader == null) {
            throw new IllegalStateException("Reader has already been closed");
        }

        // grab the next feature
        SimpleFeature next = reader.next();

        Object[] attributes = next.getAttributes().toArray();

        try {
            for (int i = 0; i < attributes.length; i++) {
                if (attributes[i] instanceof Geometry) {
                    attributes[i] = transformer.transform((Geometry) attributes[i]);
                }
            }
        } catch (TransformException e) {
            throw (IllegalStateException)
                    new IllegalStateException(
                                    "A transformation exception occurred while reprojecting data on the fly")
                            .initCause(e);
        }

        return SimpleFeatureBuilder.build(schema, attributes, next.getID());
    }

    public void remove() {
        throw new UnsupportedOperationException("On the fly reprojection disables remove");
    }
    /**
     * Implement hasNext.
     *
     * 
Description ...
     *
     * @see org.geotools.data.FeatureReader#hasNext()
     */
    public boolean hasNext() {
        if (reader == null) {
            throw new IllegalStateException("Reader has already been closed");
        }

        return reader.hasNext();
    }

    /**
     * Implement close.
     *
     * Description ...
     *
     * @see org.geotools.data.FeatureReader#close()
     */
    public void close() {
        if (reader == null) {
            return;
        }
        reader.close();
        reader = null;
        schema = null;
    }
}