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.data.dataset;
031
032import java.util.AbstractMap;
033import java.util.Iterator;
034import java.util.Set;
035
036import org.openimaj.io.InputStreamObjectReader;
037import org.openimaj.io.ObjectReader;
038import org.openimaj.util.iterator.ConcatenatedIterable;
039
040/**
041 * Base class for {@link GroupedDataset}s in which each instance is read with an
042 * {@link InputStreamObjectReader}.
043 *
044 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
045 *
046 * @param <KEY>
047 *            Type of dataset class key
048 * @param <DATASET>
049 *            Type of sub-datasets.
050 * @param <INSTANCE>
051 *            Type of instances in the dataset
052 * @param <SOURCE>
053 *            the type of object that provides the data to create the instance
054 */
055public abstract class ReadableGroupDataset<KEY, DATASET extends Dataset<INSTANCE>, INSTANCE, SOURCE>
056extends AbstractMap<KEY, DATASET>
057implements GroupedDataset<KEY, DATASET, INSTANCE>
058{
059        protected ObjectReader<INSTANCE, SOURCE> reader;
060
061        /**
062         * Construct with the given {@link InputStreamObjectReader}.
063         *
064         * @param reader
065         *            the {@link InputStreamObjectReader}.
066         */
067        public ReadableGroupDataset(ObjectReader<INSTANCE, SOURCE> reader) {
068                this.reader = reader;
069        }
070
071        @Override
072        public INSTANCE getRandomInstance() {
073                final int index = (int) (Math.random() * numInstances());
074                int count = 0;
075
076                for (final KEY key : this.getGroups()) {
077                        final DATASET group = getInstances(key);
078
079                        if (count + group.numInstances() > index) {
080                                if (group instanceof ListDataset) {
081                                        return ((ListDataset<INSTANCE>) group).get(index - count);
082                                } else {
083                                        for (final INSTANCE i : group) {
084                                                if (index == count)
085                                                        return i;
086
087                                                count++;
088                                        }
089                                }
090                        } else {
091                                count += group.numInstances();
092                        }
093                }
094                return null;
095        }
096
097        @Override
098        public int numInstances() {
099                int size = 0;
100
101                for (final KEY key : this.getGroups()) {
102                        size += this.getInstances(key).numInstances();
103                }
104
105                return size;
106        }
107
108        @Override
109        public Iterator<INSTANCE> iterator() {
110                return new ConcatenatedIterable<INSTANCE>(this.values()).iterator();
111        }
112
113        @Override
114        public DATASET getInstances(KEY key) {
115                return this.get(key);
116        }
117
118        @Override
119        public Set<KEY> getGroups() {
120                return this.keySet();
121        }
122
123        @Override
124        public INSTANCE getRandomInstance(KEY key) {
125                return get(key).getRandomInstance();
126        }
127}