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.util.stream.combine;
031
032import org.openimaj.util.function.Function;
033import org.openimaj.util.pair.IndependentPair;
034
035/**
036 * Given a combined stream (i.e. a stream of {@link IndependentPair} instances)
037 * apply two functions (one to each component of the pair) to produce a stream
038 * of output pairs.
039 * 
040 * @author Sina Samangooei (ss@ecs.soton.ac.uk)
041 * 
042 * @param <AIN>
043 *            The first part of the input pair
044 * @param <BIN>
045 *            The second part of the input pair
046 * 
047 * @param <AOUT>
048 *            The first part of the output pair
049 * @param <BOUT>
050 *            The second part of the output pair
051 * 
052 */
053public class CombinedStreamFunction<AIN, AOUT, BIN, BOUT>
054                implements
055                Function<IndependentPair<AIN, BIN>, IndependentPair<AOUT, BOUT>>
056{
057        private Function<AIN, AOUT> fA;
058        private Function<BIN, BOUT> fB;
059
060        /**
061         * Construct with the given functions to apply to the first and second
062         * elements of the pairs in the input stream respectively.
063         * 
064         * @param fA
065         *            function to apply to the first element
066         * @param fB
067         *            function to apply to the second element
068         */
069        public CombinedStreamFunction(Function<AIN, AOUT> fA, Function<BIN, BOUT> fB) {
070                this.fA = fA;
071                this.fB = fB;
072        }
073
074        @Override
075        public IndependentPair<AOUT, BOUT> apply(IndependentPair<AIN, BIN> in) {
076                return IndependentPair.pair(fA.apply(in.firstObject()), fB.apply(in.secondObject()));
077        }
078}