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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.io.IOException;
import java.util.NoSuchElementException;
import org.geotools.data.DataSourceException;
import org.geotools.data.DelegatingFeatureReader;
import org.geotools.data.FeatureReader;
import org.geotools.feature.FeatureTypes;
import org.geotools.feature.SchemaException;
import org.geotools.feature.simple.SimpleFeatureBuilder;
import org.geotools.geometry.jts.GeometryCoordinateSequenceTransformer;
import org.geotools.referencing.CRS;
import org.locationtech.jts.geom.Geometry;
import org.opengis.feature.IllegalAttributeException;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.referencing.FactoryException;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
import org.opengis.referencing.operation.MathTransform;
import org.opengis.referencing.operation.OperationNotFoundException;
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 ReprojectFeatureReader
        implements DelegatingFeatureReader {

    FeatureReader reader;
    SimpleFeatureType schema;
    GeometryCoordinateSequenceTransformer transformer = new GeometryCoordinateSequenceTransformer();

    /**
     * Direct constructor reprojecting the provided reader into the schema indicated (using the
     * supplied math transformation).
     *
     * Please note schema is that of the expected results, You may need to use
     * FeatureTypes.transform( FeatureType, crs ) to create the schema provider.
     *
     * @param reader original reader with results in the original coordinate reference system
     * @param schema This is the target schema describing the results in the expected coordinate
     *     reference system
     * @param transform the math transform used to go from reader coordinate reference system to the
     *     provided schema coordinate reference system
     */
    public ReprojectFeatureReader(
            FeatureReader reader,
            SimpleFeatureType schema,
            MathTransform transform) {
        this.reader = reader;
        this.schema = schema;
        transformer.setMathTransform(transform);
    }
    /**
     * Constructor that will generate schema and mathTransform for the results.
     *
     * @param reader original reader
     * @param cs Target coordinate reference system; will be used to create the target FeatureType
     *     and MathTransform used to transform the data
     */
    public ReprojectFeatureReader(
            FeatureReader reader, CoordinateReferenceSystem cs)
            throws SchemaException, OperationNotFoundException, NoSuchElementException,
                    FactoryException {
        if (cs == null) {
            throw new NullPointerException("CoordinateSystem required");
        }

        SimpleFeatureType type = reader.getFeatureType();
        CoordinateReferenceSystem original =
                type.getGeometryDescriptor().getCoordinateReferenceSystem();

        if (cs.equals(original)) {
            throw new IllegalArgumentException(
                    "CoordinateSystem " + cs + " already used (check before using wrapper)");
        }

        this.schema = FeatureTypes.transform(type, cs);
        this.reader = reader;
        transformer.setMathTransform(CRS.findMathTransform(original, cs, true));
    }

    public FeatureReader getDelegate() {
        return reader;
    }

    /**
     * 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 IOException, IllegalAttributeException, NoSuchElementException {
        if (reader == null) {
            throw new IllegalStateException("Reader has already been closed");
        }

        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 new DataSourceException(
                    "A transformation exception occurred while reprojecting data on the fly", e);
        }
        // building the new reprojected feature
        SimpleFeature reprojected = SimpleFeatureBuilder.build(schema, attributes, next.getID());
        // copying the user data if any
        if (next.hasUserData()) {
            reprojected.getUserData().putAll(next.getUserData());
        }
        return reprojected;
    }

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

        reader.close();
        reader = null;
        schema = null;
    }
}