Class Sequence

java.lang.Object
javax.sound.midi.Sequence
public class Sequence extends Object
A Sequence is a data structure containing musical information (often an entire song or composition) that can be played back by a Sequencer object. Specifically, the Sequence contains timing information and one or more tracks. Each track consists of a series of MIDI events (such as note-ons, note-offs, program changes, and meta-events). The sequence's timing information specifies the type of unit that is used to time-stamp the events in the sequence.

A Sequence can be created from a MIDI file by reading the file into an input stream and invoking one of the getSequence methods of MidiSystem. A sequence can also be built from scratch by adding new Tracks to an empty Sequence, and adding MidiEvent objects to these Tracks.

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Field Summary

Modifier and Type Field Description
protected float divisionType
The timing division type of the sequence.
static final float PPQ
The tempo-based timing type, for which the resolution is expressed in pulses (ticks) per quarter note.
protected int resolution
The timing resolution of the sequence.
static final float SMPTE_24
The SMPTE-based timing type with 24 frames per second (resolution is expressed in ticks per frame).
static final float SMPTE_25
The SMPTE-based timing type with 25 frames per second (resolution is expressed in ticks per frame).
static final float SMPTE_30
The SMPTE-based timing type with 30 frames per second (resolution is expressed in ticks per frame).
static final float SMPTE_30DROP
The SMPTE-based timing type with 29.97 frames per second (resolution is expressed in ticks per frame).
protected Vector<Track> tracks
The MIDI tracks in this sequence.

Constructor Summary

Constructor Description
Sequence(float divisionType, int resolution)
Constructs a new MIDI sequence with the specified timing division type and timing resolution.
Sequence(float divisionType, int resolution, int numTracks)
Constructs a new MIDI sequence with the specified timing division type, timing resolution, and number of tracks.

Method Summary

Modifier and Type Method Description
Track createTrack()
Creates a new, initially empty track as part of this sequence.
boolean deleteTrack(Track track)
Removes the specified track from the sequence.
float getDivisionType()
Obtains the timing division type for this sequence.
long getMicrosecondLength()
Obtains the duration of this sequence, expressed in microseconds.
Patch[] getPatchList()
Obtains a list of patches referenced in this sequence.
int getResolution()
Obtains the timing resolution for this sequence.
long getTickLength()
Obtains the duration of this sequence, expressed in MIDI ticks.
Track[] getTracks()
Obtains an array containing all the tracks in this sequence.

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

PPQ

public static final float PPQ
The tempo-based timing type, for which the resolution is expressed in pulses (ticks) per quarter note.
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SMPTE_24

public static final float SMPTE_24
The SMPTE-based timing type with 24 frames per second (resolution is expressed in ticks per frame).
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SMPTE_25

public static final float SMPTE_25
The SMPTE-based timing type with 25 frames per second (resolution is expressed in ticks per frame).
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SMPTE_30DROP

public static final float SMPTE_30DROP
The SMPTE-based timing type with 29.97 frames per second (resolution is expressed in ticks per frame).
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SMPTE_30

public static final float SMPTE_30
The SMPTE-based timing type with 30 frames per second (resolution is expressed in ticks per frame).
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divisionType

protected float divisionType
The timing division type of the sequence.
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resolution

protected int resolution
The timing resolution of the sequence.
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tracks

protected Vector<Track> tracks
The MIDI tracks in this sequence.
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Constructor Details

Sequence

public Sequence(float divisionType, int resolution) throws InvalidMidiDataException
Constructs a new MIDI sequence with the specified timing division type and timing resolution. The division type must be one of the recognized MIDI timing types. For tempo-based timing, divisionType is PPQ (pulses per quarter note) and the resolution is specified in ticks per beat. For SMTPE timing, divisionType specifies the number of frames per second and the resolution is specified in ticks per frame. The sequence will contain no initial tracks. Tracks may be added to or removed from the sequence using createTrack() and deleteTrack(javax.sound.midi.Track).
Parameters:
divisionType - the timing division type (PPQ or one of the SMPTE types)
resolution - the timing resolution
Throws:
InvalidMidiDataException - if divisionType is not valid
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Sequence

public Sequence(float divisionType, int resolution, int numTracks) throws InvalidMidiDataException
Constructs a new MIDI sequence with the specified timing division type, timing resolution, and number of tracks. The division type must be one of the recognized MIDI timing types. For tempo-based timing, divisionType is PPQ (pulses per quarter note) and the resolution is specified in ticks per beat. For SMTPE timing, divisionType specifies the number of frames per second and the resolution is specified in ticks per frame. The sequence will be initialized with the number of tracks specified by numTracks. These tracks are initially empty (i.e. they contain only the meta-event End of Track). The tracks may be retrieved for editing using the getTracks() method. Additional tracks may be added, or existing tracks removed, using createTrack() and deleteTrack(javax.sound.midi.Track).
Parameters:
divisionType - the timing division type (PPQ or one of the SMPTE types)
resolution - the timing resolution
numTracks - the initial number of tracks in the sequence
Throws:
InvalidMidiDataException - if divisionType is not valid
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Method Details

getDivisionType

public float getDivisionType()
Obtains the timing division type for this sequence.
Returns:
the division type (PPQ or one of the SMPTE types)
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getResolution

public int getResolution()
Obtains the timing resolution for this sequence. If the sequence's division type is PPQ, the resolution is specified in ticks per beat. For SMTPE timing, the resolution is specified in ticks per frame.
Returns:
the number of ticks per beat (PPQ) or per frame (SMPTE)
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createTrack

public Track createTrack()
Creates a new, initially empty track as part of this sequence. The track initially contains the meta-event End of Track. The newly created track is returned. All tracks in the sequence may be retrieved using getTracks(). Tracks may be removed from the sequence using deleteTrack(javax.sound.midi.Track).
Returns:
the newly created track

deleteTrack

public boolean deleteTrack(Track track)
Removes the specified track from the sequence.
Parameters:
track - the track to remove
Returns:
true if the track existed in the track and was removed, otherwise false
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getTracks

public Track[] getTracks()
Obtains an array containing all the tracks in this sequence. If the sequence contains no tracks, an array of length 0 is returned.
Returns:
the array of tracks
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getMicrosecondLength

public long getMicrosecondLength()
Obtains the duration of this sequence, expressed in microseconds.
Returns:
this sequence's duration in microseconds

getTickLength

public long getTickLength()
Obtains the duration of this sequence, expressed in MIDI ticks.
Returns:
this sequence's length in ticks
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getPatchList

public Patch[] getPatchList()
Obtains a list of patches referenced in this sequence. This patch list may be used to load the required Instrument objects into a Synthesizer.
Returns:
an array of Patch objects used in this sequence
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