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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) 2018, 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.util;

import java.io.Closeable;
import java.util.Iterator;
import java.util.Spliterators;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import org.geotools.feature.FeatureCollection;
import org.geotools.feature.FeatureIterator;
import org.opengis.feature.Feature;
import org.opengis.feature.type.FeatureType;

/**
 * Provides toStream transform methods for Feature Collection & Iterator
 *
 * @author Fernando Miño, Geosolutions
 */
public final class FeatureStreams {

    private FeatureStreams() {}

    /**
     * Converts FeatureCollection to Stream of Features Use with try-with-resources clause for auto
     * closing
     */
    public static  Stream toFeatureStream(
            FeatureCollection fc) {
        @SuppressWarnings("PMD.CloseResource") // wrapped and returned
        StreamFeatureIterator fi = new StreamFeatureIterator<>(fc.features());
        return StreamSupport.stream(Spliterators.spliteratorUnknownSize(fi, 0), false)
                .onClose(
                        () -> {
                            fi.close();
                        });
    }

    /**
     * Iterator Wrapper for use on streams
     *
     * @author Fernando Miño, Geosolutions
     * @param 
     */
    public static class StreamFeatureIterator
            implements Closeable, Iterator, FeatureIterator {

        private FeatureIterator delegate;

        public StreamFeatureIterator(FeatureIterator fiter) {
            delegate = fiter;
        }

        @Override
        public boolean hasNext() {
            return delegate.hasNext();
        }

        @Override
        public F next() {
            return delegate.next();
        }

        @Override
        public void close() {
            delegate.close();
        }
    }
}