MidiMessage (Java SE 15 & JDK 15) (original) (raw)

All Implemented Interfaces:

[Cloneable](../../../../java.base/java/lang/Cloneable.html "interface in java.lang")

Direct Known Subclasses:

[MetaMessage](MetaMessage.html "class in javax.sound.midi"), [ShortMessage](ShortMessage.html "class in javax.sound.midi"), [SysexMessage](SysexMessage.html "class in javax.sound.midi")

public abstract class MidiMessage extends Object implements Cloneable

MidiMessage is the base class for MIDI messages. They include not only the standard MIDI messages that a synthesizer can respond to, but also "meta-events" that can be used by sequencer programs. There are meta-events for such information as lyrics, copyrights, tempo indications, time and key signatures, markers, etc. For more information, see the Standard MIDI Files 1.0 specification, which is part of the Complete MIDI 1.0 Detailed Specification published by the MIDI Manufacturer's Association (http://www.midi.org).

The base MidiMessage class provides access to three types of information about a MIDI message:

• The messages's status byte
• The total length of the message in bytes (the status byte plus any data bytes)
• A byte array containing the complete message

MidiMessage includes methods to get, but not set, these values. Setting them is a subclass responsibility.

The MIDI standard expresses MIDI data in bytes. However, because Java uses signed bytes, the Java Sound API uses integers instead of bytes when expressing MIDI data. For example, thegetStatus() method of MidiMessage returns MIDI status bytes as integers. If you are processing MIDI data that originated outside Java Sound and now is encoded as signed bytes, the bytes can be converted to integers using this conversion:

int i = (int)(byte & 0xFF)

If you simply need to pass a known MIDI byte value as a method parameter, it can be expressed directly as an integer, using (for example) decimal or hexadecimal notation. For instance, to pass the "active sensing" status byte as the first argument to ShortMessage'ssetMessage(int) method, you can express it as 254 or 0xFE.

See Also:

Track, Sequence, Receiver

• Field Summary

Fields

• Constructor Summary

Constructors

• Method Summary

• Field Details

  • data

  protected byte[] data
  The MIDI message data. The first byte is the status byte for the message; subsequent bytes up to the length of the message are data bytes for this message.
  See Also:
  getLength()

  • length

  protected int length
  The number of bytes in the MIDI message, including the status byte and any data bytes.
  See Also:
  getLength()

• Constructor Details

  • MidiMessage

  protected MidiMessage​(byte[] data)
  Constructs a new MidiMessage. This protected constructor is called by concrete subclasses, which should ensure that the data array specifies a complete, valid MIDI message.
  Parameters:
  data - an array of bytes containing the complete message. The message data may be changed using the setMessage method.
  See Also:
  setMessage(byte[], int)

• Method Details

  • setMessage

  Sets the data for the MIDI message. This protected method is called by concrete subclasses, which should ensure that the data array specifies a complete, valid MIDI message.
  Parameters:
  data - the data bytes in the MIDI message
  length - the number of bytes in the data byte array
  Throws:
  [InvalidMidiDataException](InvalidMidiDataException.html "class in javax.sound.midi") - if the parameter values do not specify a valid MIDI meta message

  • getMessage

  public byte[] getMessage()
  Obtains the MIDI message data. The first byte of the returned byte array is the status byte of the message. Any subsequent bytes up to the length of the message are data bytes. The byte array may have a length which is greater than that of the actual message; the total length of the message in bytes is reported by the getLength() method.
  Returns:
  the byte array containing the complete MidiMessage data

  • getStatus

  public int getStatus()
  Obtains the status byte for the MIDI message. The status "byte" is represented as an integer; see thediscussion in the MidiMessage class description.
  Returns:
  the integer representation of this event's status byte

  • getLength

  public int getLength()
  Obtains the total length of the MIDI message in bytes. A MIDI message consists of one status byte and zero or more data bytes. The return value ranges from 1 for system real-time messages, to 2 or 3 for channel messages, to any value for meta and system exclusive messages.
  Returns:
  the length of the message in bytes

  • clone

  public abstract Object clone()
  Creates a new object of the same class and with the same contents as this object.
  Overrides:
  [clone](../../../../java.base/java/lang/Object.html#clone%28%29) in class [Object](../../../../java.base/java/lang/Object.html "class in java.lang")
  Returns:
  a clone of this instance
  See Also:
  Cloneable