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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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
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 *
 * 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).
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 * 2 along with this work; if not, write to the Free Software Foundation,
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package javax.sound.midi;

import java.io.InputStream;
import java.io.IOException;


/**
 * A hardware or software device that plays back a MIDI
 * <code>{@link Sequence sequence}</code> is known as a <em>sequencer</em>.
 * A MIDI sequence contains lists of time-stamped MIDI data, such as
 * might be read from a standard MIDI file.  Most
 * sequencers also provide functions for creating and editing sequences.
 * <p>
 * The <code>Sequencer</code> interface includes methods for the following
 * basic MIDI sequencer operations:
 * <ul>
 * <li>obtaining a sequence from MIDI file data</li>
 * <li>starting and stopping playback</li>
 * <li>moving to an arbitrary position in the sequence</li>
 * <li>changing the tempo (speed) of playback</li>
 * <li>synchronizing playback to an internal clock or to received MIDI
 * messages</li>
 * <li>controlling the timing of another device</li>
 * </ul>
 * In addition, the following operations are supported, either directly, or
 * indirectly through objects that the <code>Sequencer</code> has access to:
 * <ul>
 * <li>editing the data by adding or deleting individual MIDI events or entire
 * tracks</li>
 * <li>muting or soloing individual tracks in the sequence</li>
 * <li>notifying listener objects about any meta-events or
 * control-change events encountered while playing back the sequence.</li>
 * </ul>
 *
 * @see Sequencer.SyncMode
 * @see #addMetaEventListener
 * @see ControllerEventListener
 * @see Receiver
 * @see Transmitter
 * @see MidiDevice
 *
 * @author Kara Kytle
 * @author Florian Bomers
 */
public interface Sequencer extends MidiDevice {


    /**
     * A value indicating that looping should continue
     * indefinitely rather than complete after a specific
     * number of loops.
     *
     * @see #setLoopCount
     * @since 1.5
     */
    public static final int LOOP_CONTINUOUSLY = -1;


    /**
     * Sets the current sequence on which the sequencer operates.
     *
     * <p>This method can be called even if the
     * <code>Sequencer</code> is closed.
     *
     * @param sequence the sequence to be loaded.
     * @throws InvalidMidiDataException if the sequence contains invalid
     * MIDI data, or is not supported.
     */
    public void setSequence(Sequence sequence) throws InvalidMidiDataException;


    /**
     * Sets the current sequence on which the sequencer operates.
     * The stream must point to MIDI file data.
     *
     * <p>This method can be called even if the
     * <code>Sequencer</code> is closed.
     *
     * @param stream stream containing MIDI file data.
     * @throws IOException if an I/O exception occurs during reading of the stream.
     * @throws InvalidMidiDataException if invalid data is encountered
     * in the stream, or the stream is not supported.
     */
    public void setSequence(InputStream stream) throws IOException, InvalidMidiDataException;


    /**
     * Obtains the sequence on which the Sequencer is currently operating.
     *
     * <p>This method can be called even if the
     * <code>Sequencer</code> is closed.
     *
     * @return the current sequence, or <code>null</code> if no sequence is currently set.
     */
    public Sequence getSequence();


    /**
     * Starts playback of the MIDI data in the currently
     * loaded sequence.
     * Playback will begin from the current position.
     * If the playback position reaches the loop end point,
     * and the loop count is greater than 0, playback will
     * resume at the loop start point for the number of
     * repetitions set with <code>setLoopCount</code>.
     * After that, or if the loop count is 0, playback will
     * continue to play to the end of the sequence.
     *
     * <p>The implementation ensures that the synthesizer
     * is brought to a consistent state when jumping
     * to the loop start point by sending appropriate
     * controllers, pitch bend, and program change events.
     *
     * @throws IllegalStateException if the <code>Sequencer</code> is
     * closed.
     *
     * @see #setLoopStartPoint
     * @see #setLoopEndPoint
     * @see #setLoopCount
     * @see #stop
     */
    public void start();


    /**
     * Stops recording, if active, and playback of the currently loaded sequence,
     * if any.
     *
     * @throws IllegalStateException if the <code>Sequencer</code> is
     * closed.
     *
     * @see #start
     * @see #isRunning
     */
    public void stop();


    /**
     * Indicates whether the Sequencer is currently running.  The default is <code>false</code>.
     * The Sequencer starts running when either <code>{@link #start}</code> or <code>{@link #startRecording}</code>
     * is called.  <code>isRunning</code> then returns <code>true</code> until playback of the
     * sequence completes or <code>{@link #stop}</code> is called.
     * @return <code>true</code> if the Sequencer is running, otherwise <code>false</code>
     */
    public boolean isRunning();


    /**
     * Starts recording and playback of MIDI data.  Data is recorded to all enabled tracks,
     * on the channel(s) for which they were enabled.  Recording begins at the current position
     * of the sequencer.   Any events already in the track are overwritten for the duration
     * of the recording session.  Events from the currently loaded sequence,
     * if any, are delivered to the sequencer's transmitter(s) along with messages
     * received during recording.
     * <p>
     * Note that tracks are not by default enabled for recording.  In order to record MIDI data,
     * at least one track must be specifically enabled for recording.
     *
     * @throws IllegalStateException if the <code>Sequencer</code> is
     * closed.
     *
     * @see #startRecording
     * @see #recordEnable
     * @see #recordDisable
     */
    public void startRecording();


    /**
     * Stops recording, if active.  Playback of the current sequence continues.
     *
     * @throws IllegalStateException if the <code>Sequencer</code> is
     * closed.
     *
     * @see #startRecording
     * @see #isRecording
     */
    public void stopRecording();


    /**
     * Indicates whether the Sequencer is currently recording.  The default is <code>false</code>.
     * The Sequencer begins recording when <code>{@link #startRecording}</code> is called,
     * and then returns <code>true</code> until <code>{@link #stop}</code> or <code>{@link #stopRecording}</code>
     * is called.
     * @return <code>true</code> if the Sequencer is recording, otherwise <code>false</code>
     */
    public boolean isRecording();


    /**
     * Prepares the specified track for recording events received on a particular channel.
     * Once enabled, a track will receive events when recording is active.
     * @param track the track to which events will be recorded
     * @param channel the channel on which events will be received.  If -1 is specified
     * for the channel value, the track will receive data from all channels.
     * @throws IllegalArgumentException thrown if the track is not part of the current
     * sequence.
     */
    public void recordEnable(Track track, int channel);


    /**
     * Disables recording to the specified track.  Events will no longer be recorded
     * into this track.
     * @param track the track to disable for recording, or <code>null</code> to disable
     * recording for all tracks.
     */
    public void recordDisable(Track track);


    /**
     * Obtains the current tempo, expressed in beats per minute.  The
     * actual tempo of playback is the product of the returned value
     * and the tempo factor.
     *
     * @return the current tempo in beats per minute
     *
     * @see #getTempoFactor
     * @see #setTempoInBPM(float)
     * @see #getTempoInMPQ
     */
    public float getTempoInBPM();


    /**
     * Sets the tempo in beats per minute.   The actual tempo of playback
     * is the product of the specified value and the tempo factor.
     *
     * @param bpm desired new tempo in beats per minute
     * @see #getTempoFactor
     * @see #setTempoInMPQ(float)
     * @see #getTempoInBPM
     */
    public void setTempoInBPM(float bpm);


    /**
     * Obtains the current tempo, expressed in microseconds per quarter
     * note.  The actual tempo of playback is the product of the returned
     * value and the tempo factor.
     *
     * @return the current tempo in microseconds per quarter note
     * @see #getTempoFactor
     * @see #setTempoInMPQ(float)
     * @see #getTempoInBPM
     */
    public float getTempoInMPQ();


    /**
     * Sets the tempo in microseconds per quarter note.  The actual tempo
     * of playback is the product of the specified value and the tempo
     * factor.
     *
     * @param mpq desired new tempo in microseconds per quarter note.
     * @see #getTempoFactor
     * @see #setTempoInBPM(float)
     * @see #getTempoInMPQ
     */
    public void setTempoInMPQ(float mpq);


    /**
     * Scales the sequencer's actual playback tempo by the factor provided.
     * The default is 1.0.  A value of 1.0 represents the natural rate (the
     * tempo specified in the sequence), 2.0 means twice as fast, etc.
     * The tempo factor does not affect the values returned by
     * <code>{@link #getTempoInMPQ}</code> and <code>{@link #getTempoInBPM}</code>.
     * Those values indicate the tempo prior to scaling.
     * <p>
     * Note that the tempo factor cannot be adjusted when external
     * synchronization is used.  In that situation,
     * <code>setTempoFactor</code> always sets the tempo factor to 1.0.
     *
     * @param factor the requested tempo scalar
     * @see #getTempoFactor
     */
    public void setTempoFactor(float factor);


    /**
     * Returns the current tempo factor for the sequencer.  The default is
     * 1.0.
     *
     * @return tempo factor.
     * @see #setTempoFactor(float)
     */
    public float getTempoFactor();


    /**
     * Obtains the length of the current sequence, expressed in MIDI ticks,
     * or 0 if no sequence is set.
     * @return length of the sequence in ticks
     */
    public long getTickLength();


    /**
     * Obtains the current position in the sequence, expressed in MIDI
     * ticks.  (The duration of a tick in seconds is determined both by
     * the tempo and by the timing resolution stored in the
     * <code>{@link Sequence}</code>.)
     *
     * @return current tick
     * @see #setTickPosition
     */
    public long getTickPosition();


    /**
     * Sets the current sequencer position in MIDI ticks
     * @param tick the desired tick position
     * @see #getTickPosition
     */
    public void setTickPosition(long tick);


    /**
     * Obtains the length of the current sequence, expressed in microseconds,
     * or 0 if no sequence is set.
     * @return length of the sequence in microseconds.
     */
    public long getMicrosecondLength();


    /**
     * Obtains the current position in the sequence, expressed in
     * microseconds.
     * @return the current position in microseconds
     * @see #setMicrosecondPosition
     */
    public long getMicrosecondPosition();


    /**
     * Sets the current position in the sequence, expressed in microseconds
     * @param microseconds desired position in microseconds
     * @see #getMicrosecondPosition
     */
    public void setMicrosecondPosition(long microseconds);


    /**
     * Sets the source of timing information used by this sequencer.
     * The sequencer synchronizes to the master, which is the internal clock,
     * MIDI clock, or MIDI time code, depending on the value of
     * <code>sync</code>.  The <code>sync</code> argument must be one
     * of the supported modes, as returned by
     * <code>{@link #getMasterSyncModes}</code>.
     *
     * @param sync the desired master synchronization mode
     *
     * @see SyncMode#INTERNAL_CLOCK
     * @see SyncMode#MIDI_SYNC
     * @see SyncMode#MIDI_TIME_CODE
     * @see #getMasterSyncMode
     */
    public void setMasterSyncMode(SyncMode sync);


    /**
     * Obtains the current master synchronization mode for this sequencer.
     *
     * @return the current master synchronization mode
     *
     * @see #setMasterSyncMode(Sequencer.SyncMode)
     * @see #getMasterSyncModes
     */
    public SyncMode getMasterSyncMode();


    /**
     * Obtains the set of master synchronization modes supported by this
     * sequencer.
     *
     * @return the available master synchronization modes
     *
     * @see SyncMode#INTERNAL_CLOCK
     * @see SyncMode#MIDI_SYNC
     * @see SyncMode#MIDI_TIME_CODE
     * @see #getMasterSyncMode
     * @see #setMasterSyncMode(Sequencer.SyncMode)
     */
    public SyncMode[] getMasterSyncModes();


    /**
     * Sets the slave synchronization mode for the sequencer.
     * This indicates the type of timing information sent by the sequencer
     * to its receiver.  The <code>sync</code> argument must be one
     * of the supported modes, as returned by
     * <code>{@link #getSlaveSyncModes}</code>.
     *
     * @param sync the desired slave synchronization mode
     *
     * @see SyncMode#MIDI_SYNC
     * @see SyncMode#MIDI_TIME_CODE
     * @see SyncMode#NO_SYNC
     * @see #getSlaveSyncModes
     */
    public void setSlaveSyncMode(SyncMode sync);


    /**
     * Obtains the current slave synchronization mode for this sequencer.
     *
     * @return the current slave synchronization mode
     *
     * @see #setSlaveSyncMode(Sequencer.SyncMode)
     * @see #getSlaveSyncModes
     */
    public SyncMode getSlaveSyncMode();


    /**
     * Obtains the set of slave synchronization modes supported by the sequencer.
     *
     * @return the available slave synchronization modes
     *
     * @see SyncMode#MIDI_SYNC
     * @see SyncMode#MIDI_TIME_CODE
     * @see SyncMode#NO_SYNC
     */
    public SyncMode[] getSlaveSyncModes();


    /**
     * Sets the mute state for a track.  This method may fail for a number
     * of reasons.  For example, the track number specified may not be valid
     * for the current sequence, or the sequencer may not support this functionality.
     * An application which needs to verify whether this operation succeeded should
     * follow this call with a call to <code>{@link #getTrackMute}</code>.
     *
     * @param track the track number.  Tracks in the current sequence are numbered
     * from 0 to the number of tracks in the sequence minus 1.
     * @param mute the new mute state for the track.  <code>true</code> implies the
     * track should be muted, <code>false</code> implies the track should be unmuted.
     * @see #getSequence
     */
    public void setTrackMute(int track, boolean mute);


    /**
     * Obtains the current mute state for a track.  The default mute
     * state for all tracks which have not been muted is false.  In any
     * case where the specified track has not been muted, this method should
     * return false.  This applies if the sequencer does not support muting
     * of tracks, and if the specified track index is not valid.
     *
     * @param track the track number.  Tracks in the current sequence are numbered
     * from 0 to the number of tracks in the sequence minus 1.
     * @return <code>true</code> if muted, <code>false</code> if not.
     */
    public boolean getTrackMute(int track);

    /**
     * Sets the solo state for a track.  If <code>solo</code> is <code>true</code>
     * only this track and other solo'd tracks will sound. If <code>solo</code>
     * is <code>false</code> then only other solo'd tracks will sound, unless no
     * tracks are solo'd in which case all un-muted tracks will sound.
     * <p>
     * This method may fail for a number
     * of reasons.  For example, the track number specified may not be valid
     * for the current sequence, or the sequencer may not support this functionality.
     * An application which needs to verify whether this operation succeeded should
     * follow this call with a call to <code>{@link #getTrackSolo}</code>.
     *
     * @param track the track number.  Tracks in the current sequence are numbered
     * from 0 to the number of tracks in the sequence minus 1.
     * @param solo the new solo state for the track.  <code>true</code> implies the
     * track should be solo'd, <code>false</code> implies the track should not be solo'd.
     * @see #getSequence
     */
    public void setTrackSolo(int track, boolean solo);


    /**
     * Obtains the current solo state for a track.  The default mute
     * state for all tracks which have not been solo'd is false.  In any
     * case where the specified track has not been solo'd, this method should
     * return false.  This applies if the sequencer does not support soloing
     * of tracks, and if the specified track index is not valid.
     *
     * @param track the track number.  Tracks in the current sequence are numbered
     * from 0 to the number of tracks in the sequence minus 1.
     * @return <code>true</code> if solo'd, <code>false</code> if not.
     */
    public boolean getTrackSolo(int track);


    /**
     * Registers a meta-event listener to receive
     * notification whenever a meta-event is encountered in the sequence
     * and processed by the sequencer. This method can fail if, for
     * instance,this class of sequencer does not support meta-event
     * notification.
     *
     * @param listener listener to add
     * @return <code>true</code> if the listener was successfully added,
     * otherwise <code>false</code>
     *
     * @see #removeMetaEventListener
     * @see MetaEventListener
     * @see MetaMessage
     */
    public boolean addMetaEventListener(MetaEventListener listener);


    /**
     * Removes the specified meta-event listener from this sequencer's
     * list of registered listeners, if in fact the listener is registered.
     *
     * @param listener the meta-event listener to remove
     * @see #addMetaEventListener
     */
    public void removeMetaEventListener(MetaEventListener listener);


    /**
     * Registers a controller event listener to receive notification
     * whenever the sequencer processes a control-change event of the
     * requested type or types.  The types are specified by the
     * <code>controllers</code> argument, which should contain an array of
     * MIDI controller numbers.  (Each number should be between 0 and 127,
     * inclusive.  See the MIDI 1.0 Specification for the numbers that
     * correspond to various types of controllers.)
     * <p>
     * The returned array contains the MIDI controller
     * numbers for which the listener will now receive events.
     * Some sequencers might not support controller event notification, in
     * which case the array has a length of 0.  Other sequencers might
     * support notification for some controllers but not all.
     * This method may be invoked repeatedly.
     * Each time, the returned array indicates all the controllers
     * that the listener will be notified about, not only the controllers
     * requested in that particular invocation.
     *
     * @param listener the controller event listener to add to the list of
     * registered listeners
     * @param controllers the MIDI controller numbers for which change
     * notification is requested
     * @return the numbers of all the MIDI controllers whose changes will
     * now be reported to the specified listener
     *
     * @see #removeControllerEventListener
     * @see ControllerEventListener
     */
    public int[] addControllerEventListener(ControllerEventListener listener, int[] controllers);


    /**
     * Removes a controller event listener's interest in one or more
     * types of controller event. The <code>controllers</code> argument
     * is an array of MIDI numbers corresponding to the  controllers for
     * which the listener should no longer receive change notifications.
     * To completely remove this listener from the list of registered
     * listeners, pass in <code>null</code> for <code>controllers</code>.
     * The returned array contains the MIDI controller
     * numbers for which the listener will now receive events.  The
     * array has a length of 0 if the listener will not receive
     * change notifications for any controllers.
     *
     * @param listener old listener
     * @param controllers the MIDI controller numbers for which change
     * notification should be cancelled, or <code>null</code> to cancel
     * for all controllers
     * @return the numbers of all the MIDI controllers whose changes will
     * now be reported to the specified listener
     *
     * @see #addControllerEventListener
     */
    public int[] removeControllerEventListener(ControllerEventListener listener, int[] controllers);


    /**
     * Sets the first MIDI tick that will be
     * played in the loop. If the loop count is
     * greater than 0, playback will jump to this
     * point when reaching the loop end point.
     *
     * <p>A value of 0 for the starting point means the
     * beginning of the loaded sequence. The starting
     * point must be lower than or equal to the ending
     * point, and it must fall within the size of the
     * loaded sequence.
     *
     * <p>A sequencer's loop start point defaults to
     * start of the sequence.
     *
     * @param tick the loop's starting position,
     *        in MIDI ticks (zero-based)
     * @throws IllegalArgumentException if the requested
     *         loop start point cannot be set, usually because
     *         it falls outside the sequence's
     *         duration or because the start point is
     *         after the end point
     *
     * @see #setLoopEndPoint
     * @see #setLoopCount
     * @see #getLoopStartPoint
     * @see #start
     * @since 1.5
     */
    public void setLoopStartPoint(long tick);


    /**
     * Obtains the start position of the loop,
     * in MIDI ticks.
     *
     * @return the start position of the loop,
               in MIDI ticks (zero-based)
     * @see #setLoopStartPoint
     * @since 1.5
     */
    public long getLoopStartPoint();


    /**
     * Sets the last MIDI tick that will be played in
     * the loop. If the loop count is 0, the loop end
     * point has no effect and playback continues to
     * play when reaching the loop end point.
     *
     * <p>A value of -1 for the ending point
     * indicates the last tick of the sequence.
     * Otherwise, the ending point must be greater
     * than or equal to the starting point, and it must
     * fall within the size of the loaded sequence.
     *
     * <p>A sequencer's loop end point defaults to -1,
     * meaning the end of the sequence.
     *
     * @param tick the loop's ending position,
     *        in MIDI ticks (zero-based), or
     *        -1 to indicate the final tick
     * @throws IllegalArgumentException if the requested
     *         loop point cannot be set, usually because
     *         it falls outside the sequence's
     *         duration or because the ending point is
     *         before the starting point
     *
     * @see #setLoopStartPoint
     * @see #setLoopCount
     * @see #getLoopEndPoint
     * @see #start
     * @since 1.5
     */
    public void setLoopEndPoint(long tick);


    /**
     * Obtains the end position of the loop,
     * in MIDI ticks.
     *
     * @return the end position of the loop, in MIDI
     *         ticks (zero-based), or -1 to indicate
     *         the end of the sequence
     * @see #setLoopEndPoint
     * @since 1.5
     */
    public long getLoopEndPoint();


    /**
     * Sets the number of repetitions of the loop for
     * playback.
     * When the playback position reaches the loop end point,
     * it will loop back to the loop start point
     * <code>count</code> times, after which playback will
     * continue to play to the end of the sequence.
     * <p>
     * If the current position when this method is invoked
     * is greater than the loop end point, playback
     * continues to the end of the sequence without looping,
     * unless the loop end point is changed subsequently.
     * <p>
     * A <code>count</code> value of 0 disables looping:
     * playback will continue at the loop end point, and it
     * will not loop back to the loop start point.
     * This is a sequencer's default.
     *
     * <p>If playback is stopped during looping, the
     * current loop status is cleared; subsequent start
     * requests are not affected by an interrupted loop
     * operation.
     *
     * @param count the number of times playback should
     *        loop back from the loop's end position
     *        to the loop's start position, or
     *        <code>{@link #LOOP_CONTINUOUSLY}</code>
     *        to indicate that looping should
     *        continue until interrupted
     *
     * @throws IllegalArgumentException if <code>count</code> is
     * negative and not equal to {@link #LOOP_CONTINUOUSLY}
     *
     * @see #setLoopStartPoint
     * @see #setLoopEndPoint
     * @see #getLoopCount
     * @see #start
     * @since 1.5
     */
    public void setLoopCount(int count);


    /**
     * Obtains the number of repetitions for
     * playback.
     *
     * @return the number of loops after which
     *         playback plays to the end of the
     *         sequence
     * @see #setLoopCount
     * @see #start
     * @since 1.5
     */
    public int getLoopCount();

    /**
     * A <code>SyncMode</code> object represents one of the ways in which
     * a MIDI sequencer's notion of time can be synchronized with a master
     * or slave device.
     * If the sequencer is being synchronized to a master, the
     * sequencer revises its current time in response to messages from
     * the master.  If the sequencer has a slave, the sequencer
     * similarly sends messages to control the slave's timing.
     * <p>
     * There are three predefined modes that specify possible masters
     * for a sequencer: <code>INTERNAL_CLOCK</code>,
     * <code>MIDI_SYNC</code>, and <code>MIDI_TIME_CODE</code>.  The
     * latter two work if the sequencer receives MIDI messages from
     * another device.  In these two modes, the sequencer's time gets reset
     * based on system real-time timing clock messages or MIDI time code
     * (MTC) messages, respectively.  These two modes can also be used
     * as slave modes, in which case the sequencer sends the corresponding
     * types of MIDI messages to its receiver (whether or not the sequencer
     * is also receiving them from a master).  A fourth mode,
     * <code>NO_SYNC</code>, is used to indicate that the sequencer should
     * not control its receiver's timing.
     *
     * @see Sequencer#setMasterSyncMode(Sequencer.SyncMode)
     * @see Sequencer#setSlaveSyncMode(Sequencer.SyncMode)
     */
    public static class SyncMode {

        /**
         * Synchronization mode name.
         */
        private String name;

        /**
         * Constructs a synchronization mode.
         * @param name name of the synchronization mode
         */
        protected SyncMode(String name) {

            this.name = name;
        }


        /**
         * Determines whether two objects are equal.
         * Returns <code>true</code> if the objects are identical
         * @param obj the reference object with which to compare
         * @return <code>true</code> if this object is the same as the
         * <code>obj</code> argument, <code>false</code> otherwise
         */
        public final boolean equals(Object obj) {

            return super.equals(obj);
        }


        /**
         * Finalizes the hashcode method.
         */
        public final int hashCode() {

            return super.hashCode();
        }


        /**
         * Provides this synchronization mode's name as the string
         * representation of the mode.
         * @return the name of this synchronization mode
         */
        public final String toString() {

            return name;
        }


        /**
         * A master synchronization mode that makes the sequencer get
         * its timing information from its internal clock.  This is not
         * a legal slave sync mode.
         */
        public static final SyncMode INTERNAL_CLOCK             = new SyncMode("Internal Clock");


        /**
         * A master or slave synchronization mode that specifies the
         * use of MIDI clock
         * messages.  If this mode is used as the master sync mode,
         * the sequencer gets its timing information from system real-time
         * MIDI clock messages.  This mode only applies as the master sync
         * mode for sequencers that are also MIDI receivers.  If this is the
         * slave sync mode, the sequencer sends system real-time MIDI clock
         * messages to its receiver.  MIDI clock messages are sent at a rate
         * of 24 per quarter note.
         */
        public static final SyncMode MIDI_SYNC                  = new SyncMode("MIDI Sync");


        /**
         * A master or slave synchronization mode that specifies the
         * use of MIDI Time Code.
         * If this mode is used as the master sync mode,
         * the sequencer gets its timing information from MIDI Time Code
         * messages.  This mode only applies as the master sync
         * mode to sequencers that are also MIDI receivers.  If this
         * mode is used as the
         * slave sync mode, the sequencer sends MIDI Time Code
         * messages to its receiver.  (See the MIDI 1.0 Detailed
         * Specification for a description of MIDI Time Code.)
         */
        public static final SyncMode MIDI_TIME_CODE             = new SyncMode("MIDI Time Code");


        /**
         * A slave synchronization mode indicating that no timing information
         * should be sent to the receiver.  This is not a legal master sync
         * mode.
         */
        public static final SyncMode NO_SYNC                            = new SyncMode("No Timing");

    } // class SyncMode
}