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.ml.annotation.basic.util;
031
032import java.util.List;
033import java.util.Random;
034
035import org.openimaj.ml.annotation.Annotated;
036
037/**
038 * Choose a random number of annotations between the given
039 * limits.
040 * 
041 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
042 */
043public class RandomChooser implements NumAnnotationsChooser {
044        protected final Random rng = new Random();
045        protected int min;
046        protected int max;
047
048        /**
049         * Construct so that the maximum possible number of annotations
050         * is max and the minimum is 0.
051         * @param max the maximum possible number of annotations
052         */
053        public RandomChooser(int max) {
054                this.max = max;
055        }
056        
057        /**
058         * Construct so that the minimium possible number of annotations
059         * is min and the maximum is max.
060         * @param min the minimium possible number of annotations
061         * @param max the maximum possible number of annotations
062         */
063        public RandomChooser(int min, int max) {
064                this.min = min;
065                this.max = max;
066        }
067        
068        @Override
069        public <O, A> void train(List<? extends Annotated<O, A>> data) {
070                //Do nothing
071        }
072
073        @Override
074        public int numAnnotations() {
075                return rng.nextInt(min + max) - min;
076        }
077}