public interface

Sequencer

implements MidiDevice
javax.sound.midi.Sequencer

Class Overview

A hardware or software device that plays back a MIDI sequence is known as a sequencer. 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.

The Sequencer interface includes methods for the following basic MIDI sequencer operations:

  • obtaining a sequence from MIDI file data
  • starting and stopping playback
  • moving to an arbitrary position in the sequence
  • changing the tempo (speed) of playback
  • synchronizing playback to an internal clock or to received MIDI messages
  • controlling the timing of another device
In addition, the following operations are supported, either directly, or indirectly through objects that the Sequencer has access to:
  • editing the data by adding or deleting individual MIDI events or entire tracks
  • muting or soloing individual tracks in the sequence
  • notifying listener objects about any meta-events or control-change events encountered while playing back the sequence.

Summary

Nested Classes
class Sequencer.SyncMode A SyncMode object represents one of the ways in which a MIDI sequencer's notion of time can be synchronized with a master or slave device. 
Constants
int LOOP_CONTINUOUSLY A value indicating that looping should continue indefinitely rather than complete after a specific number of loops.
Public Methods
abstract int[] addControllerEventListener(ControllerEventListener listener, int[] controllers)
Registers a controller event listener to receive notification whenever the sequencer processes a control-change event of the requested type or types.
abstract boolean addMetaEventListener(MetaEventListener listener)
Registers a meta-event listener to receive notification whenever a meta-event is encountered in the sequence and processed by the sequencer.
abstract int getLoopCount()
Obtains the number of repetitions for playback.
abstract long getLoopEndPoint()
Obtains the end position of the loop, in MIDI ticks.
abstract long getLoopStartPoint()
Obtains the start position of the loop, in MIDI ticks.
abstract Sequencer.SyncMode getMasterSyncMode()
Obtains the current master synchronization mode for this sequencer.
abstract SyncMode[] getMasterSyncModes()
Obtains the set of master synchronization modes supported by this sequencer.
abstract long getMicrosecondLength()
Obtains the length of the current sequence, expressed in microseconds, or 0 if no sequence is set.
abstract long getMicrosecondPosition()
Obtains the current position in the sequence, expressed in microseconds.
abstract Sequence getSequence()
Obtains the sequence on which the Sequencer is currently operating.
abstract Sequencer.SyncMode getSlaveSyncMode()
Obtains the current slave synchronization mode for this sequencer.
abstract SyncMode[] getSlaveSyncModes()
Obtains the set of slave synchronization modes supported by the sequencer.
abstract float getTempoFactor()
Returns the current tempo factor for the sequencer.
abstract float getTempoInBPM()
Obtains the current tempo, expressed in beats per minute.
abstract float getTempoInMPQ()
Obtains the current tempo, expressed in microseconds per quarter note.
abstract long getTickLength()
Obtains the length of the current sequence, expressed in MIDI ticks, or 0 if no sequence is set.
abstract long getTickPosition()
Obtains the current position in the sequence, expressed in MIDI ticks.
abstract boolean getTrackMute(int track)
Obtains the current mute state for a track.
abstract boolean getTrackSolo(int track)
Obtains the current solo state for a track.
abstract boolean isRecording()
Indicates whether the Sequencer is currently recording.
abstract boolean isRunning()
Indicates whether the Sequencer is currently running.
abstract void recordDisable(Track track)
Disables recording to the specified track.
abstract void recordEnable(Track track, int channel)
Prepares the specified track for recording events received on a particular channel.
abstract int[] removeControllerEventListener(ControllerEventListener listener, int[] controllers)
Removes a controller event listener's interest in one or more types of controller event.
abstract void removeMetaEventListener(MetaEventListener listener)
Removes the specified meta-event listener from this sequencer's list of registered listeners, if in fact the listener is registered.
abstract void setLoopCount(int count)
Sets the number of repetitions of the loop for playback.
abstract void setLoopEndPoint(long tick)
Sets the last MIDI tick that will be played in the loop.
abstract void setLoopStartPoint(long tick)
Sets the first MIDI tick that will be played in the loop.
abstract void setMasterSyncMode(Sequencer.SyncMode sync)
Sets the source of timing information used by this sequencer.
abstract void setMicrosecondPosition(long microseconds)
Sets the current position in the sequence, expressed in microseconds
abstract void setSequence(InputStream stream)
Sets the current sequence on which the sequencer operates.
abstract void setSequence(Sequence sequence)
Sets the current sequence on which the sequencer operates.
abstract void setSlaveSyncMode(Sequencer.SyncMode sync)
Sets the slave synchronization mode for the sequencer.
abstract void setTempoFactor(float factor)
Scales the sequencer's actual playback tempo by the factor provided.
abstract void setTempoInBPM(float bpm)
Sets the tempo in beats per minute.
abstract void setTempoInMPQ(float mpq)
Sets the tempo in microseconds per quarter note.
abstract void setTickPosition(long tick)
Sets the current sequencer position in MIDI ticks
abstract void setTrackMute(int track, boolean mute)
Sets the mute state for a track.
abstract void setTrackSolo(int track, boolean solo)
Sets the solo state for a track.
abstract void start()
Starts playback of the MIDI data in the currently loaded sequence.
abstract void startRecording()
Starts recording and playback of MIDI data.
abstract void stop()
Stops recording, if active, and playback of the currently loaded sequence, if any.
abstract void stopRecording()
Stops recording, if active.
[Expand]
Inherited Methods
From interface javax.sound.midi.MidiDevice

Constants

public static final int LOOP_CONTINUOUSLY

A value indicating that looping should continue indefinitely rather than complete after a specific number of loops.

Constant Value: -1 (0xffffffff)

Public Methods

public abstract int[] addControllerEventListener (ControllerEventListener listener, int[] controllers)

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 controllers 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.)

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.

Parameters
listener the controller event listener to add to the list of registered listeners
controllers the MIDI controller numbers for which change notification is requested
Returns
  • the numbers of all the MIDI controllers whose changes will now be reported to the specified listener

public abstract boolean addMetaEventListener (MetaEventListener listener)

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.

Parameters
listener listener to add
Returns
  • true if the listener was successfully added, otherwise false

public abstract int getLoopCount ()

Obtains the number of repetitions for playback.

Returns
  • the number of loops after which playback plays to the end of the sequence

public abstract long getLoopEndPoint ()

Obtains the end position of the loop, in MIDI ticks.

Returns
  • the end position of the loop, in MIDI ticks (zero-based), or -1 to indicate the end of the sequence

public abstract long getLoopStartPoint ()

Obtains the start position of the loop, in MIDI ticks.

Returns
  • the start position of the loop, in MIDI ticks (zero-based)

public abstract Sequencer.SyncMode getMasterSyncMode ()

Obtains the current master synchronization mode for this sequencer.

Returns
  • the current master synchronization mode

public abstract SyncMode[] getMasterSyncModes ()

Obtains the set of master synchronization modes supported by this sequencer.

Returns
  • the available master synchronization modes

public abstract long getMicrosecondLength ()

Obtains the length of the current sequence, expressed in microseconds, or 0 if no sequence is set.

Returns
  • length of the sequence in microseconds.

public abstract long getMicrosecondPosition ()

Obtains the current position in the sequence, expressed in microseconds.

Returns
  • the current position in microseconds

public abstract Sequence getSequence ()

Obtains the sequence on which the Sequencer is currently operating.

This method can be called even if the Sequencer is closed.

Returns
  • the current sequence, or null if no sequence is currently set.

public abstract Sequencer.SyncMode getSlaveSyncMode ()

Obtains the current slave synchronization mode for this sequencer.

Returns
  • the current slave synchronization mode

public abstract SyncMode[] getSlaveSyncModes ()

Obtains the set of slave synchronization modes supported by the sequencer.

Returns
  • the available slave synchronization modes

public abstract float getTempoFactor ()

Returns the current tempo factor for the sequencer. The default is 1.0.

Returns
  • tempo factor.

public abstract float getTempoInBPM ()

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.

Returns
  • the current tempo in beats per minute

public abstract float getTempoInMPQ ()

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.

Returns
  • the current tempo in microseconds per quarter note

public abstract long getTickLength ()

Obtains the length of the current sequence, expressed in MIDI ticks, or 0 if no sequence is set.

Returns
  • length of the sequence in ticks

public abstract long getTickPosition ()

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 Sequence.)

Returns
  • current tick

public abstract boolean getTrackMute (int track)

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.

Parameters
track the track number. Tracks in the current sequence are numbered from 0 to the number of tracks in the sequence minus 1.
Returns
  • true if muted, false if not.

public abstract boolean getTrackSolo (int track)

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.

Parameters
track the track number. Tracks in the current sequence are numbered from 0 to the number of tracks in the sequence minus 1.
Returns
  • true if solo'd, false if not.

public abstract boolean isRecording ()

Indicates whether the Sequencer is currently recording. The default is false. The Sequencer begins recording when startRecording() is called, and then returns true until stop() or stopRecording() is called.

Returns
  • true if the Sequencer is recording, otherwise false

public abstract boolean isRunning ()

Indicates whether the Sequencer is currently running. The default is false. The Sequencer starts running when either start() or startRecording() is called. isRunning then returns true until playback of the sequence completes or stop() is called.

Returns
  • true if the Sequencer is running, otherwise false

public abstract void recordDisable (Track track)

Disables recording to the specified track. Events will no longer be recorded into this track.

Parameters
track the track to disable for recording, or null to disable recording for all tracks.

public abstract void recordEnable (Track track, int channel)

Prepares the specified track for recording events received on a particular channel. Once enabled, a track will receive events when recording is active.

Parameters
track the track to which events will be recorded
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 abstract int[] removeControllerEventListener (ControllerEventListener listener, int[] controllers)

Removes a controller event listener's interest in one or more types of controller event. The controllers 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 null for controllers. 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.

Parameters
listener old listener
controllers the MIDI controller numbers for which change notification should be cancelled, or null to cancel for all controllers
Returns
  • the numbers of all the MIDI controllers whose changes will now be reported to the specified listener

public abstract void removeMetaEventListener (MetaEventListener listener)

Removes the specified meta-event listener from this sequencer's list of registered listeners, if in fact the listener is registered.

Parameters
listener the meta-event listener to remove

public abstract void setLoopCount (int count)

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 count times, after which playback will continue to play to the end of the sequence.

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.

A count 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.

If playback is stopped during looping, the current loop status is cleared; subsequent start requests are not affected by an interrupted loop operation.

Parameters
count the number of times playback should loop back from the loop's end position to the loop's start position, or LOOP_CONTINUOUSLY to indicate that looping should continue until interrupted
Throws
IllegalArgumentException if count is negative and not equal to LOOP_CONTINUOUSLY

public abstract void setLoopEndPoint (long tick)

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.

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.

A sequencer's loop end point defaults to -1, meaning the end of the sequence.

Parameters
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

public abstract void setLoopStartPoint (long tick)

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.

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.

A sequencer's loop start point defaults to start of the sequence.

Parameters
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

public abstract void setMasterSyncMode (Sequencer.SyncMode sync)

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 sync. The sync argument must be one of the supported modes, as returned by getMasterSyncModes().

Parameters
sync the desired master synchronization mode

public abstract void setMicrosecondPosition (long microseconds)

Sets the current position in the sequence, expressed in microseconds

Parameters
microseconds desired position in microseconds

public abstract void setSequence (InputStream stream)

Sets the current sequence on which the sequencer operates. The stream must point to MIDI file data.

This method can be called even if the Sequencer is closed.

Parameters
stream stream containing MIDI file data.
Throws
IOException if an I/O exception occurs during reading of the stream.
InvalidMidiDataException if invalid data is encountered in the stream, or the stream is not supported.

public abstract void setSequence (Sequence sequence)

Sets the current sequence on which the sequencer operates.

This method can be called even if the Sequencer is closed.

Parameters
sequence the sequence to be loaded.
Throws
InvalidMidiDataException if the sequence contains invalid MIDI data, or is not supported.

public abstract void setSlaveSyncMode (Sequencer.SyncMode sync)

Sets the slave synchronization mode for the sequencer. This indicates the type of timing information sent by the sequencer to its receiver. The sync argument must be one of the supported modes, as returned by getSlaveSyncModes().

Parameters
sync the desired slave synchronization mode

public abstract void setTempoFactor (float factor)

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 getTempoInMPQ() and getTempoInBPM(). Those values indicate the tempo prior to scaling.

Note that the tempo factor cannot be adjusted when external synchronization is used. In that situation, setTempoFactor always sets the tempo factor to 1.0.

Parameters
factor the requested tempo scalar
See Also

public abstract void setTempoInBPM (float bpm)

Sets the tempo in beats per minute. The actual tempo of playback is the product of the specified value and the tempo factor.

Parameters
bpm desired new tempo in beats per minute

public abstract void setTempoInMPQ (float mpq)

Sets the tempo in microseconds per quarter note. The actual tempo of playback is the product of the specified value and the tempo factor.

Parameters
mpq desired new tempo in microseconds per quarter note.

public abstract void setTickPosition (long tick)

Sets the current sequencer position in MIDI ticks

Parameters
tick the desired tick position

public abstract void setTrackMute (int track, boolean mute)

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 getTrackMute(int).

Parameters
track the track number. Tracks in the current sequence are numbered from 0 to the number of tracks in the sequence minus 1.
mute the new mute state for the track. true implies the track should be muted, false implies the track should be unmuted.
See Also

public abstract void setTrackSolo (int track, boolean solo)

Sets the solo state for a track. If solo is true only this track and other solo'd tracks will sound. If solo is false then only other solo'd tracks will sound, unless no tracks are solo'd in which case all un-muted tracks will sound.

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 getTrackSolo(int).

Parameters
track the track number. Tracks in the current sequence are numbered from 0 to the number of tracks in the sequence minus 1.
solo the new solo state for the track. true implies the track should be solo'd, false implies the track should not be solo'd.
See Also

public abstract void start ()

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 setLoopCount. After that, or if the loop count is 0, playback will continue to play to the end of the sequence.

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 Sequencer is closed.

public abstract void startRecording ()

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.

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 Sequencer is closed.

public abstract void stop ()

Stops recording, if active, and playback of the currently loaded sequence, if any.

Throws
IllegalStateException if the Sequencer is closed.

public abstract void stopRecording ()

Stops recording, if active. Playback of the current sequence continues.

Throws
IllegalStateException if the Sequencer is closed.