001    /* MidiMessage.java -- base class for MIDI messages.
002       Copyright (C) 2005 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package javax.sound.midi;
040    
041    /**
042     * The base class for all MIDI messages.
043     * 
044     * @author Anthony Green (green@redhat.com)
045     * @since 1.3
046     *
047     */
048    public abstract class MidiMessage implements Cloneable
049    {
050      /**
051       * MIDI message data.
052       */
053      protected byte data[];
054      
055      /**
056       * The total length of the MIDI message.
057       */
058      protected int length;
059      
060      /**
061       * MidiMessage contructor.
062       * 
063       * @param data a valid MIDI message
064       */
065      protected MidiMessage(byte[] data)
066      {
067        this.data = data;
068        this.length = data.length;
069      }
070      
071      /**
072       * Set the complete MIDI message.
073       * 
074       * @param data The complete MIDI message.
075       * @param length The length of the MIDI message.
076       * @throws InvalidMidiDataException Thrown when the MIDI message is invalid.
077       */
078      protected void setMessage(byte[] data, int length) 
079        throws InvalidMidiDataException
080      {
081        this.data = new byte[length];
082        System.arraycopy(data, 0, this.data, 0, length);
083        this.length = length;
084      }
085      
086      /**
087       * Get the MIDI message data.
088       * 
089       * @return an array containing the MIDI message data
090       */
091      public byte[] getMessage()
092      {
093        byte copy[] = new byte[length];
094        System.arraycopy(data, 0, copy, 0, length);
095        return copy;    
096      }
097      
098      /**
099       * Get the status byte of the MIDI message (as an int)
100       * 
101       * @return the status byte of the MIDI message (as an int), or zero if the message length is zero.
102       */
103      public int getStatus()
104      {
105        if (length > 0)
106          return (data[0] & 0xff);
107        else 
108          return 0;
109      }
110      
111      /**
112       * Get the length of the MIDI message.
113       * 
114       * @return the length of the MIDI messsage
115       */
116      public int getLength()
117      {
118        return length;
119      }
120      
121      /* Create a clone of this object.
122       * 
123       * @see java.lang.Object#clone()
124       */
125      public abstract Object clone();
126    }