# 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`.

See Also:
  - `Sequencer.setSequence(java.io.InputStream stream)`
  - `Sequencer.setSequence(Sequence sequence)`
  - `Track.add(MidiEvent)`
  - `MidiFileFormat`

- ## Field Summary

  Fields
  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

  Constructors
  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.
    See Also:
      - `Sequence(float, int)`
      - Constant Field Values

  - ### 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).
    See Also:
      - `Sequence(float, int)`
      - Constant Field Values

  - ### 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).
    See Also:
      - `Sequence(float, int)`
      - Constant Field Values

  - ### 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).
    See Also:
      - `Sequence(float, int)`
      - Constant Field Values

  - ### 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).
    See Also:
      - `Sequence(float, int)`
      - Constant Field Values

  - ### divisionType

    protected float divisionType
    The timing division type of the sequence.
    See Also:
      - `PPQ`
      - `SMPTE_24`
      - `SMPTE_25`
      - `SMPTE_30DROP`
      - `SMPTE_30`
      - `getDivisionType()`

  - ### resolution

    protected int resolution
    The timing resolution of the sequence.
    See Also:
      - `getResolution()`

  - ### tracks

    protected Vector<Track> tracks
    The MIDI tracks in this sequence.
    See Also:
      - `getTracks()`

- ## 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 SMPTE 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
    See Also:
      - `PPQ`
      - `SMPTE_24`
      - `SMPTE_25`
      - `SMPTE_30DROP`
      - `SMPTE_30`
      - `getDivisionType()`
      - `getResolution()`
      - `getTracks()`

  - ### 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 SMPTE 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
    See Also:
      - `PPQ`
      - `SMPTE_24`
      - `SMPTE_25`
      - `SMPTE_30DROP`
      - `SMPTE_30`
      - `getDivisionType()`
      - `getResolution()`

- ## 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)
    See Also:
      - `PPQ`
      - `SMPTE_24`
      - `SMPTE_25`
      - `SMPTE_30DROP`
      - `SMPTE_30`
      - `Sequence(float, int)`
      - `MidiFileFormat.getDivisionType()`

  - ### 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 SMPTE timing, the resolution is specified in ticks per frame.
    Returns:
      the number of ticks per beat (PPQ) or per frame (SMPTE)
    See Also:
      - `getDivisionType()`
      - `Sequence(float, int)`
      - `MidiFileFormat.getResolution()`

  - ### 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`
    See Also:
      - `createTrack()`
      - `getTracks()`

  - ### 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
    See Also:
      - `createTrack()`
      - `deleteTrack(javax.sound.midi.Track)`

  - ### 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
    See Also:
      - `getMicrosecondLength()`

  - ### 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
    See Also:
      - `Synthesizer.loadInstruments(Soundbank, Patch[])`