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.hadoop.sequencefile;
031
032import java.util.List;
033
034import org.apache.hadoop.io.BytesWritable;
035import org.semanticdesktop.aperture.mime.identifier.magic.MagicMimeTypeIdentifier;
036
037/**
038 * Strategies for naming files extracted from SequenceFiles.
039 * 
040 * @author Sina Samangooei (ss@ecs.soton.ac.uk)
041 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
042 */
043public enum NamingStrategy {
044        /**
045         * Use the key value as the filename
046         */
047        KEY {
048                @Override
049                public <K, V> String getNameInternal(K key, V value, ExtractionState state) {
050                        return key.toString();
051                }
052        },
053        /**
054         * Number the files sequentially
055         */
056        NUMERICAL {
057                @Override
058                public <K, V> String getNameInternal(K key, V value, ExtractionState state) {
059                        return "" + state.getCount();
060                }
061        };
062
063        protected abstract <K, V> String getNameInternal(K key, V value, ExtractionState state);
064
065        /**
066         * Generate the filename for the given record (key-value pair). If the
067         * addExtension flag is true AND the value is a {@link BytesWritable}, then
068         * a mime-type sniffing process takes place in order to "guess" an extension
069         * which will be added to the end of the generated filename.
070         * 
071         * @param <K>
072         *            key type
073         * @param <V>
074         *            value type
075         * @param key
076         *            the key
077         * @param value
078         *            the value
079         * @param state
080         *            the extraction state
081         * @param addExtension
082         *            should the file extension be guessed and added automatically
083         * @return the filename
084         */
085        public <K, V> String getName(K key, V value, ExtractionState state, boolean addExtension) {
086                String name = this.getNameInternal(key, value, state);
087
088                if (addExtension && value instanceof BytesWritable) {
089                        final MagicMimeTypeIdentifier match = new MagicMimeTypeIdentifier();
090
091                        final String mime = match.identify(((BytesWritable) value).getBytes(), key.toString(), null);
092
093                        @SuppressWarnings("unchecked")
094                        final List<String> exts = match.getExtensionsFor(mime);
095
096                        if (exts.size() > 0)
097                                name += "." + exts.get(0);
098                }
099
100                return name;
101        }
102}