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.util.Iterator;
033
034/**
035 * Abstract base class for {@link DataSource} implementations. Simplifies
036 * implementation by providing {@link #iterator()} and
037 * {@link #getRandomRows(Object[])} methods that proxy their work to
038 * {@link #getData(int)}.
039 * 
040 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
041 * 
042 * @param <DATATYPE>
043 *            the data type which can be returned
044 */
045public abstract class AbstractDataSource<DATATYPE> implements DataSource<DATATYPE> {
046        @Override
047        public Iterator<DATATYPE> iterator() {
048                return new Iterator<DATATYPE>() {
049                        int index = 0;
050
051                        @Override
052                        public boolean hasNext() {
053                                return (index + 1) < size();
054                        }
055
056                        @Override
057                        public DATATYPE next() {
058                                index++;
059
060                                return getData(index);
061                        }
062
063                        @Override
064                        public void remove() {
065                                throw new UnsupportedOperationException();
066                        }
067                };
068        }
069
070        @Override
071        public void getRandomRows(DATATYPE[] data) {
072                final int[] rndIndexes = RandomData.getUniqueRandomInts(data.length, 0, size());
073
074                for (int i = 0; i < rndIndexes.length; i++)
075                        data[i] = getData(rndIndexes[i]);
076        }
077}