JavaTM 2 Platform
Std. Ed. v1.4.2

Class Track

  extended byjavax.sound.midi.Track

public class Track
extends Object

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.

A Track occupies a middle level in the hierarchy of data played by a Sequencer: sequencers play sequences, which contain tracks, which contain MIDI events. A sequencer may provide controls that mute or solo individual tracks.

The timing information and resolution for a track is controlled by and stored in the sequence containing the track. A given Track is considered to belong to the particular Sequence that maintains its timing. For this reason, a new (empty) track is created by calling the Sequence.createTrack() method, rather than by directly invoking a Track constructor.

The Track class provides methods to edit the track by adding or removing MidiEvent 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 Also:
Sequencer.setTrackMute(int, boolean), Sequencer.setTrackSolo(int, boolean)

Field Summary
protected  Vector events
          The list of MidiEvents contained in this track.
Method Summary
 boolean add(MidiEvent event)
          Adds a new event to the track.
 MidiEvent get(int index)
          Obtains the event at the specified index.
 boolean remove(MidiEvent event)
          Removes the specified event from the track.
 int size()
          Obtains the number of events in this track.
 long ticks()
          Obtains the length of the track, expressed in MIDI ticks.
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail


protected Vector events
The list of MidiEvents contained in this track.

Method Detail


public boolean add(MidiEvent event)
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.

event - the event to add
true if the event did not already exist in the track and was added, otherwise false


public boolean remove(MidiEvent event)
Removes the specified event from the track.

event - the event to remove
true if the event existed in the track and was removed, otherwise false


public MidiEvent get(int index)
              throws ArrayIndexOutOfBoundsException
Obtains the event at the specified index.

index - the location of the desired event in the event vector
ArrayIndexOutOfBoundsException - if the specified index is negative or not less than the current size of this track.
See Also:


public int size()
Obtains the number of events in this track.

the size of the track's event vector


public long ticks()
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 Sequence containing this track, and also by the tempo of the music as set by the sequencer.)

the duration, in ticks
See Also:
Sequence.Sequence(float, int), Sequencer.setTempoInBPM(float), Sequencer.getTickPosition()

JavaTM 2 Platform
Std. Ed. v1.4.2

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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