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;
031
032import java.lang.reflect.Array;
033import java.util.ArrayList;
034import java.util.Arrays;
035import java.util.List;
036import java.util.Map;
037
038/**
039 * An abstract {@link DataSource} backed by multiple lists of data.
040 *
041 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
042 * @param <DATATYPE>
043 *            the data type which can be returned
044 * @param <ELEMENTTYPE>
045 *            the datatype of the underlying lists
046 *
047 */
048public abstract class AbstractMultiListDataSource<DATATYPE, ELEMENTTYPE> extends AbstractDataSource<DATATYPE> {
049        protected List<? extends List<ELEMENTTYPE>> data;
050
051        /**
052         * Construct with the given lists of data
053         *
054         * @param data
055         *            the data
056         */
057        public AbstractMultiListDataSource(List<? extends List<ELEMENTTYPE>> data) {
058                this.data = data;
059        }
060
061        /**
062         * Construct with the given lists of data
063         *
064         * @param data
065         *            the data
066         */
067        @SafeVarargs
068        public AbstractMultiListDataSource(List<ELEMENTTYPE>... data) {
069                this.data = Arrays.asList(data);
070        }
071
072        /**
073         * Construct with the given map of data. The keys are ignored, and only the
074         * values are used.
075         *
076         * @param data
077         *            the data
078         */
079        public AbstractMultiListDataSource(Map<?, ? extends List<ELEMENTTYPE>> data) {
080                this.data = new ArrayList<List<ELEMENTTYPE>>(data.values());
081        }
082
083        @Override
084        public void getData(int startRow, int stopRow, DATATYPE[] data) {
085                for (int i = 0, row = startRow; row < stopRow; row++, i++) {
086                        data[i] = getData(row);
087                }
088        }
089
090        @Override
091        public DATATYPE getData(int row) {
092                int cumsum = 0;
093
094                for (int i = 0; i < data.size(); i++) {
095                        final int sz = data.get(i).size();
096
097                        if (row < cumsum + sz) {
098                                return convert(data.get(i).get(row - cumsum));
099                        }
100
101                        cumsum += sz;
102                }
103
104                throw new IndexOutOfBoundsException();
105        }
106
107        /**
108         * Convert an item's type
109         *
110         * @param ele
111         *            the input item
112         * @return the converted item
113         */
114        protected abstract DATATYPE convert(ELEMENTTYPE ele);
115
116        @Override
117        public int size() {
118                int sum = 0;
119
120                for (final List<ELEMENTTYPE> d : data)
121                        sum += d.size();
122
123                return sum;
124        }
125
126        @SuppressWarnings("unchecked")
127        @Override
128        public DATATYPE[] createTemporaryArray(int size) {
129                return (DATATYPE[]) Array.newInstance(getData(0).getClass(), size);
130        }
131}