File	Doc	Category	Size	Date	Package
MetaMessage.java	API Doc	Java SE 5 API	7334	Fri Aug 26 14:57:48 BST 2005	javax.sound.midi

MetaMessage

• java.lang.Object
  • javax.sound.midi.MidiMessage

Fields Summary
public static final int	META Status byte for MetaMessage (0xFF, or 255), which is used in MIDI files. It has the same value as SYSTEM_RESET, which is used in the real-time "MIDI wire" protocol.
private static byte[]	defaultMessage
private int	dataLength The length of the actual message in the data array. This is used to determine how many bytes of the data array is the message, and how many are the status byte, the type byte, and the variable-length-int describing the length of the message.
private static final long	mask

Constructors Summary
public MetaMessage() Constructs a new MetaMessage. The contents of the message are not set here; use {@link #setMessage(int, byte[], int) setMessage} to set them subsequently. //super(defaultMessage); this(defaultMessage);
protected MetaMessage(byte[] data) Constructs a new MetaMessage. param data an array of bytes containing the complete message. The message data may be changed using the setMessage method. see #setMessage super(data); //$$fb 2001-10-06: need to calculate dataLength. Fix for bug #4511796 if (data.length>=3) { dataLength=data.length-3; int pos=2; while (pos<data.length && (data[pos] & 0x80)!=0) { dataLength--; pos++; } }

Methods Summary
public java.lang.Object	clone() Creates a new object of the same class and with the same contents as this object. return a clone of this instance byte[] newData = new byte[length]; System.arraycopy(data, 0, newData, 0, newData.length); MetaMessage event = new MetaMessage(newData); return event;
public byte[]	getData() Obtains a copy of the data for the meta message. The returned array of bytes does not include the status byte or the message length data. The length of the data for the meta message is the length of the array. Note that the length of the entire message includes the status byte and the meta message type byte, and therefore may be longer than the returned array. return array containing the meta message data. see MidiMessage#getLength byte[] returnedArray = new byte[dataLength]; System.arraycopy(data, (length - dataLength), returnedArray, 0, dataLength); return returnedArray;
public int	getType() Obtains the type of the MetaMessage. return an integer representing the MetaMessage type if (length>=2) { return data[1] & 0xFF; } return 0;
private int	getVarIntLength(long value) int length = 0; do { value = value >> 7; length++; } while (value > 0); return length;
public void	setMessage(int type, byte[] data, int length) Sets the message parameters for a MetaMessage. Since only one status byte value, 0xFF, is allowed for meta-messages, it does not need to be specified here. Calls to {@link MidiMessage#getStatus getStatus} return 0xFF for all meta-messages. The type argument should be a valid value for the byte that follows the status byte in the MetaMessage. The data argument should contain all the subsequent bytes of the MetaMessage. In other words, the byte that specifies the type of MetaMessage is not considered a data byte. param type meta-message type (must be less than 128) param data the data bytes in the MIDI message param length the number of bytes in the data byte array throws InvalidMidiDataException if the parameter values do not specify a valid MIDI meta message if (type >= 128 || type < 0) { throw new InvalidMidiDataException("Invalid meta event with type " + type); } if ((length > 0 && length > data.length) || length < 0) { throw new InvalidMidiDataException("length out of bounds: "+length); } this.length = 2 + getVarIntLength(length) + length; this.dataLength = length; this.data = new byte[this.length]; this.data[0] = (byte) META; // status value for MetaMessages (meta events) this.data[1] = (byte) type; // MetaMessage type writeVarInt(this.data, 2, length); // write the length as a variable int if (length > 0) { System.arraycopy(data, 0, this.data, this.length - this.dataLength, this.dataLength); }
private void	writeVarInt(byte[] data, int off, long value) int shift=63; // number of bitwise left-shifts of mask // first screen out leading zeros while ((shift > 0) && ((value & (mask << shift)) == 0)) shift-=7; // then write actual values while (shift > 0) { data[off++]=(byte) (((value & (mask << shift)) >> shift) | 0x80); shift-=7; } data[off] = (byte) (value & mask);