/*
 * @(#)MidiMessage.java	1.30 05/11/17
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.sound.midi;

/**
 * <code>MidiMessage</code> 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
 * (<a href = http://www.midi.org>http://www.midi.org</a>).
 * <p>
 * The base <code>MidiMessage</code> class provides access to three types of
 * information about a MIDI message:
 * <ul>
 * <li>The messages's status byte</li>
 * <li>The total length of the message in bytes (the status byte plus any data bytes)</li>
 * <li>A byte array containing the complete message</li>
 * </ul>
 *
 * <code>MidiMessage</code> includes methods to get, but not set, these values.
 * Setting them is a subclass responsibility.
 * <p>
 * <a name="integersVsBytes"></a>
 * The MIDI standard expresses MIDI data in bytes.  However, because
 * Java<sup>TM</sup> uses signed bytes, the Java Sound API uses integers
 * instead of bytes when expressing MIDI data.  For example, the
 * {@link #getStatus()} method of
 * <code>MidiMessage</code> 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
 * can be converted to integers using this conversion:
 * <center><code>int i = (int)(byte & 0xFF)</code></center>
 * <p>
 * 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
 * hexidecimal notation.  For instance, to pass the "active sensing" status byte
 * as the first argument to ShortMessage's
 * {@link ShortMessage#setMessage(int) setMessage(int)}
 * method, you can express it as 254 or 0xFE.
 *
 * @see Track
 * @see Sequence
 * @see Receiver
 *
 * @version 1.30, 05/11/17
 * @author David Rivas
 * @author Kara Kytle
 */

public abstract class MidiMessage implements Cloneable {

    // Instance variables

    /**
     * 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 #getLength
     */
    protected byte[] data;


    /**
     * The number of bytes in the MIDI message, including the
     * status byte and any data bytes.
     * @see #getLength
     */
    protected int length = 0;


    /**
     * Constructs a new <code>MidiMessage</code>.  This protected
     * constructor is called by concrete subclasses, which should
     * ensure that the data array specifies a complete, valid MIDI
     * message.
     *
     * @param data an array of bytes containing the complete message.
     * The message data may be changed using the <code>setMessage</code>
     * method.
     *
     * @see #setMessage
     */
    protected MidiMessage(byte[] data) {
	this.data = data;
	if (data != null) {
	    this.length = data.length;
	}
    }


    /**
     * Sets the data for the MIDI message.   This protected