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/* * Copyright (c) 1999, 2006, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.sound.midi; import java.util.Vector;import java.util.ArrayList;import java.util.HashSet;import com.sun.media.sound.MidiUtils; /** * A MIDI track is an independent stream of MIDI events (time-stamped MIDI * data) that can be stored along with other tracks in a standard MIDI file. * The MIDI specification allows only 16 channels of MIDI data, but tracks * are a way to get around this limitation.  A MIDI file can contain any number * of tracks, each containing its own stream of up to 16 channels of MIDI data. * <p> * A <code>Track</code> occupies a middle level in the hierarchy of data played * by a <code>{@link Sequencer}</code>: sequencers play sequences, which contain tracks, * which contain MIDI events.  A sequencer may provide controls that mute * or solo individual tracks. * <p> * The timing information and resolution for a track is controlled by and stored * in the sequence containing the track. A given <code>Track</code> * is considered to belong to the particular <code>{@link Sequence}</code> that * maintains its timing. For this reason, a new (empty) track is created by calling the * <code>{@link Sequence#createTrack}</code> method, rather than by directly invoking a * <code>Track</code> constructor. * <p> * The <code>Track</code> class provides methods to edit the track by adding * or removing <code>MidiEvent</code> objects from it.  These operations keep * the event list in the correct time order.  Methods are also * included to obtain the track's size, in terms of either the number of events * it contains or its duration in ticks. * * @see Sequencer#setTrackMute * @see Sequencer#setTrackSolo * * @author Kara Kytle * @author Florian Bomers */public class Track {     // TODO: use arrays for faster access     // the list containing the events    private ArrayList eventsList = new ArrayList();     // use a hashset to detect duplicate events in add(MidiEvent)    private HashSet set = new HashSet();     private MidiEvent eotEvent;      /**     * Package-private constructor.  Constructs a new, empty Track object,     * which initially contains one event, the meta-event End of Track.     */    Track() {        // start with the end of track event        MetaMessage eot = new ImmutableEndOfTrack();        eotEvent = new MidiEvent(eot, 0);        eventsList.add(eotEvent);        set.add(eotEvent);    }     /**     * Adds a new event to the track.  However, if the event is already     * contained in the track, it is not added again.  The list of events     * is kept in time order, meaning that this event inserted at the     * appropriate place in the list, not necessarily at the end.     *     * @param event the event to add     * @return <code>true</code> if the event did not already exist in the     * track and was added, otherwise <code>false</code>     */    public boolean add(MidiEvent event) {        if (event == null) {            return false;        }        synchronized(eventsList) {             if (!set.contains(event)) {                int eventsCount = eventsList.size();                 // get the last event                MidiEvent lastEvent = null;                if (eventsCount > 0) {                    lastEvent = (MidiEvent) eventsList.get(eventsCount - 1);                }                // sanity check that we have a correct end-of-track                if (lastEvent != eotEvent) {                    // if there is no eot event, add our immutable instance again                    if (lastEvent != null) {                        // set eotEvent's tick to the last tick of the track                        eotEvent.setTick(lastEvent.getTick());                    } else {                        // if the events list is empty, just set the tick to 0                        eotEvent.setTick(0);                    }                    // we needn't check for a duplicate of eotEvent in "eventsList",                    // since then it would appear in the set.                    eventsList.add(eotEvent);                    set.add(eotEvent);                    eventsCount = eventsList.size();                }                 // first see if we are trying to add                // and endoftrack event.                if (MidiUtils.isMetaEndOfTrack(event.getMessage())) {                    // since end of track event is useful                    // for delays at the end of a track, we want to keep                    // the tick value requested here if it is greater                    // than the one on the eot we are maintaining.                    // Otherwise, we only want a single eot event, so ignore.                    if (event.getTick() > eotEvent.getTick()) {                        eotEvent.setTick(event.getTick());                    }                    return true;                }                 // prevent duplicates                set.add(event);                 // insert event such that events is sorted in increasing                // tick order                int i = eventsCount;                for ( ; i > 0; i--) {                    if (event.getTick() >= ((MidiEvent)eventsList.get(i-1)).getTick()) {                        break;                    }                }                if (i == eventsCount) {                    // we're adding an event after the                    // tick value of our eot, so push the eot out.                    // Always add at the end for better performance:                    // this saves all the checks and arraycopy when inserting                     // overwrite eot with new event                    eventsList.set(eventsCount - 1, event);                    // set new time of eot, if necessary                    if (eotEvent.getTick() < event.getTick()) {                        eotEvent.setTick(event.getTick());                    }                    // add eot again at the end                    eventsList.add(eotEvent);                } else {                    eventsList.add(i, event);                }                return true;            }        }         return false;    }      /**     * Removes the specified event from the track.     * @param event the event to remove     * @return <code>true</code> if the event existed in the track and was removed,     * otherwise <code>false</code>     */    public boolean remove(MidiEvent event) {         // this implementation allows removing the EOT event.        // pretty bad, but would probably be too risky to        // change behavior now, in case someone does tricks like:        //        // while (track.size() > 0) track.remove(track.get(track.size() - 1));         // also, would it make sense to adjust the EOT's time        // to the last event, if the last non-EOT event is removed?        // Or: document that the ticks() length will not be reduced        // by deleting events (unless the EOT event is removed)        synchronized(eventsList) {            if (set.remove(event)) {                int i = eventsList.indexOf(event);                if (i >= 0) {                    eventsList.remove(i);                    return true;                }            }        }        return false;    }      /**     * Obtains the event at the specified index.     * @param index the location of the desired event in the event vector     * @throws <code>ArrayIndexOutOfBoundsException</code>  if the     * specified index is negative or not less than the current size of     * this track.     * @see #size     */    public MidiEvent get(int index) throws ArrayIndexOutOfBoundsException {        try {            synchronized(eventsList) {                return (MidiEvent)eventsList.get(index);            }        } catch (IndexOutOfBoundsException ioobe) {            throw new ArrayIndexOutOfBoundsException(ioobe.getMessage());        }    }      /**     * Obtains the number of events in this track.     * @return the size of the track's event vector     */    public int size() {        synchronized(eventsList) {            return eventsList.size();        }    }      /**     * Obtains the length of the track, expressed in MIDI ticks.  (The     * duration of a tick in seconds is determined by the timing resolution     * of the <code>Sequence</code> containing this track, and also by     * the tempo of the music as set by the sequencer.)     * @return the duration, in ticks     * @see Sequence#Sequence(float, int)     * @see Sequencer#setTempoInBPM(float)     * @see Sequencer#getTickPosition()     */    public long ticks() {        long ret = 0;        synchronized (eventsList) {            if (eventsList.size() > 0) {                ret = ((MidiEvent)eventsList.get(eventsList.size() - 1)).getTick();            }        }        return ret;    }     private static class ImmutableEndOfTrack extends MetaMessage {        private ImmutableEndOfTrack() {            super(new byte[3]);            data[0] = (byte) META;            data[1] = MidiUtils.META_END_OF_TRACK_TYPE;            data[2] = 0;        }         public void setMessage(int type, byte[] data, int length) throws InvalidMidiDataException {            throw new InvalidMidiDataException("cannot modify end of track message");        }    } }