midimessage.java

java处理声音文件

/*
 *	MidiMessage.java
 */

/*
 *  Copyright (c) 1999 by Matthias Pfisterer <[e-mail]>
 *
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library General Public License as published
 *   by the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU Library General Public License for more details.
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this program; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */




package	javax.sound.midi;



public abstract class MidiMessage
	implements	Cloneable
{
	/**	All data of the message.
	 */
	private byte[]		m_abData;




	protected MidiMessage(byte[] abData)
	{
		m_abData = abData;
	}



	/**
	 */
	protected void setMessage(byte[] abData, int nLength)
		throws	InvalidMidiDataException
	{
		if (nLength < abData.length)
		{
			byte[]	abShortenedData = new byte[nLength];
			System.arraycopy(abData, 0, abShortenedData, 0, nLength);
			abData = abShortenedData;
		}
		m_abData = abData;
	}


	/**	returns the complete message.
	 *	This method does not make a copy of the array.
	 */
	public byte[] getMessage()
	{
		return m_abData;
	}



	/**	Returns the status byte of the message.
	 *	I.e. the first byte is returned. This has to be overridden
	 *	by subclasses if the status byte is not stored as part of
	 *	the data (like it is for MetaMessages).
	 *	If no message has been set, -1 is returned.
	 */
	public int getStatus()
	{
		if (m_abData != null)
		{
			if (m_abData[0] < 0)
			{
				return (int) m_abData[0] + 256;
			}
			else
			{
				return m_abData[0];
			}
		}
		else
		{
			return -1;
		}

	}



	/**
	 *	Returns the length of the message in bytes.
	 *	In this implementation, the length returned by this method
	 *	is always equal to the length of the array returned by
	 *	getMessage(). However, this has to be considered
	 *	implementation-specific behaviour. It is not guaranteed for
	 *	other implementations of the Java Sound API.
	 *	If no message has been set, a length of 0 is returned.
	 */
	public int getLength()
	{
		if (m_abData != null)
		{
			return m_abData.length;
		}
		else
		{
			return 0;
		}
	}


	public abstract Object clone();
}



/*** MidiMessage.java ***/