org.geotools.data.util.FeatureStreams Maven / Gradle / Ivy

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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();
        }
    }
}