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 */
030/**
031 *
032 */
033package org.openimaj.audio;
034
035import java.util.Iterator;
036import java.util.NoSuchElementException;
037
038/**
039 * Represents an audio stream that can be read chunk-by-chunk.
040 *
041 * @author David Dupplaw (dpd@ecs.soton.ac.uk)
042 * @created 8 Jun 2011
043 *
044 */
045public abstract class AudioStream extends Audio implements Iterable<SampleChunk>
046{
047        /**
048         * Retrieve the next SampleChunk from the audio stream.
049         *
050         * @return The next sample chunk in the audio stream.
051         */
052        public abstract SampleChunk nextSampleChunk();
053
054        /**
055         * Reset the audio stream.
056         */
057        public abstract void reset();
058
059        /**
060         * Returns the length of the audio stream in milliseconds. If the length is
061         * unknown (for a live stream for example), then this method should return
062         * -1.
063         *
064         * @return The length in milliseconds, or -1
065         */
066        public abstract long getLength();
067
068        /**
069         * Seeks the audio to the given timestamp. The timestamp of the audio should
070         * be checked after calling seek() as the seek method may not succeed if the
071         * stream does not support seeking.
072         *
073         * @param timestamp
074         *            The timestamp to seek to
075         */
076        public void seek(final long timestamp)
077        {
078                // Seek supported? Then override this method.
079        }
080
081        @Override
082        public Iterator<SampleChunk> iterator() {
083                return new Iterator<SampleChunk>() {
084                        private SampleChunk next;
085
086                        @Override
087                        public boolean hasNext() {
088                                if (next != null)
089                                        return true;
090                                next = nextSampleChunk();
091                                return next != null;
092                        }
093
094                        @Override
095                        public SampleChunk next() {
096                                if (next == null)
097                                        next = nextSampleChunk();
098
099                                final SampleChunk ret = next;
100                                next = null;
101
102                                if (ret == null)
103                                        throw new NoSuchElementException();
104
105                                return ret;
106                        }
107
108                        @Override
109                        public void remove() {
110                                throw new UnsupportedOperationException("Remove not supported");
111                        }
112                };
113        }
114}