001/**
002 * Copyright (c) 2011, The University of Southampton and the individual contributors.
003 * All rights reserved.
004 *
005 * Redistribution and use in source and binary forms, with or without modification,
006 * are permitted provided that the following conditions are met:
007 *
008 *   *  Redistributions of source code must retain the above copyright notice,
009 *      this list of conditions and the following disclaimer.
010 *
011 *   *  Redistributions in binary form must reproduce the above copyright notice,
012 *      this list of conditions and the following disclaimer in the documentation
013 *      and/or other materials provided with the distribution.
014 *
015 *   *  Neither the name of the University of Southampton nor the names of its
016 *      contributors may be used to endorse or promote products derived from this
017 *      software without specific prior written permission.
018 *
019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
020 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
021 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
022 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
023 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
026 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
028 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029 */
030package org.openimaj.stream.functions;
031
032import java.io.IOException;
033import java.io.InputStream;
034import java.net.URL;
035import java.util.ArrayList;
036import java.util.List;
037
038import org.openimaj.image.FImage;
039import org.openimaj.image.Image;
040import org.openimaj.image.ImageUtilities;
041import org.openimaj.image.MBFImage;
042import org.openimaj.io.ObjectReader;
043import org.openimaj.util.function.MultiFunction;
044import org.openimaj.util.stream.Stream;
045
046/**
047 * This class implements a function that can read images from URLs. Use in
048 * combination with a {@link Stream} to convert from URLs to {@link Image}s.
049 * 
050 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
051 * 
052 * @param <I>
053 *            The type of {@link Image}
054 */
055public class ImageFromURL<I extends Image<?, I>> implements MultiFunction<URL, I> {
056        /**
057         * Static instance of the {@link ImageFromURL} for extracting {@link FImage}s
058         */
059        public static ImageFromURL<FImage> FIMAGE_EXTRACTOR = new ImageFromURL<FImage>(ImageUtilities.FIMAGE_READER);
060
061        /**
062         * Static instance of the {@link ImageFromURL} for extracting
063         * {@link MBFImage}s
064         */
065        public static ImageFromURL<MBFImage> MBFIMAGE_EXTRACTOR = new ImageFromURL<MBFImage>(ImageUtilities.MBFIMAGE_READER);
066
067        private ObjectReader<I, InputStream> reader;
068
069        /**
070         * Construct with the given image reader.
071         * 
072         * @param reader
073         */
074        public ImageFromURL(ObjectReader<I, InputStream> reader) {
075                this.reader = reader;
076        }
077
078        @Override
079        public List<I> apply(URL in) {
080                final List<I> images = new ArrayList<I>(1);
081                InputStream stream = null;
082                try {
083                        stream = in.openStream();
084                        final I im = reader.read(stream);
085
086                        images.add(im);
087                } catch (final IOException e) {
088                        // silently ignore
089                } finally {
090                        if (stream != null) {
091                                try {
092                                        stream.close();
093                                } catch (final IOException e) {
094                                        // silently ignore
095                                }
096                        }
097                }
098
099                return images;
100        }
101}