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.content.animation.animator;
031
032/**
033 * Base class for objects capable of "animating" a value;
034 * that is providing a new value everytime {@link #nextValue()} is
035 * called, subject to some constraints.
036 * 
037 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
038 *
039 * @param <T> Type of value produced 
040 */
041public abstract class AbstractValueAnimator<T> implements ValueAnimator<T> {
042        private T currentValue;
043        
044        /**
045         * Number of times {@link #nextValue()} has been called since construction or last reset
046         */
047        private int currentCount = 0;
048        
049        private int startWait = 0;
050        private int stopWait = 0;
051        private int completedAt = -1;
052        
053        /**
054         * Construct with initial value
055         * @param initial initial value
056         * @param startWait amount of time in ticks to wait before starting animation.
057         * @param stopWait amount of time in ticks to wait after finishing animation.
058         */
059        public AbstractValueAnimator(T initial, int startWait, int stopWait) {
060                currentValue = initial;
061                this.startWait = startWait;
062                this.stopWait = stopWait;
063        }
064        
065        /**
066         * Get the next value. If the animator has finished,
067         * the continuation is checked to see if there are
068         * more animators to run. If not, then the last value 
069         * is returned. 
070         * 
071         * @return the next value.
072         */
073        @Override
074        public T nextValue() {
075                if (!(currentCount < startWait || hasFinished() || completedAt > 0)) {
076                        currentValue = makeNextValue();
077                }
078                
079                currentCount++;
080                
081                return currentValue;
082        }
083        
084        protected abstract T makeNextValue();
085        
086        protected abstract void resetToInitial();
087        
088        @Override
089        public final void reset() {
090                resetToInitial();
091                currentCount = 0;
092                completedAt = -1;
093        }
094        
095        protected abstract boolean complete();
096        
097        @Override
098        public final boolean hasFinished() {
099                boolean comp = complete();
100                
101                if (!comp)
102                        return false;
103                
104                if (completedAt < 0)
105                        completedAt = currentCount;
106                
107                if (currentCount - completedAt < stopWait) 
108                        return false;
109                
110                return true;
111        }
112}