/*
  $Id: MKNoteFilter.h,v 1.8 2005/05/09 15:52:51 leighsmith Exp $
  Defined In: The MusicKit

  Description:
    See class description below for description.    

  Original Author: David A. Jaffe

  Copyright (c) 1988-1992, NeXT Computer, Inc.
  Portions Copyright (c) 1994 NeXT Computer, Inc. and reproduced under license from NeXT
  Portions Copyright (c) 1994 Stanford University
  Portions Copyright (c) 1999-2004, The MusicKit Project.
*/
/*!
  @class MKNoteFilter
  @brief MKNoteFilter is an abstract class that combines the functionality it inherits
  from MKInstrument with the protocol defined in the MKPerformer class. 

  @brief
  MKNoteFilter is an abstract class that combines the functionality it inherits
  from MKInstrument with the protocol defined in the MKPerformer class.

  
  MKNoteFilter objects can both receive and send MKNotes; they're interposed
  between MKPerformers and MKInstruments to create a MKNote processing pipeline. 
  The subclass responsibility <b>realizeNote:fromNoteReceiver:</b> is passed on to
  MKNoteFilter subclasses. Keep in mind that notes must be copied on write or store.
*/
#ifndef __MK_NoteFilter_H___
#define __MK_NoteFilter_H___

#import "MKInstrument.h"

@interface MKNoteFilter : MKInstrument
{
    NSMutableArray *noteSenders;     /* Collection of MKNoteSenders. */
}

/*!
  @return Returns a newly initialized MKNoteFilter.
  @brief Creates MKNoteSenders and sends [super init].

  
*/
- init;

/*!
  @return Returns an NSArray instance.
  @brief Returns a copy of the receiver's NSArray of MKNoteSenders.

  
*/
- (NSArray *) noteSenders;

/*!
  @param  aNoteSender is an MKNoteSender instance.
  @return Returns a BOOL.
  @brief Returns YES if <i>aNoteSender</i> is one of the receiver's
  MKNoteSenders.

  Otherwise returns NO.
*/
- (BOOL) isNoteSenderPresent: (MKNoteSender *) aNoteSender; 

/*!
  @param  zone is a NSZone.
  @return Returns an id.
  @brief Creates and returns a MKNoteFilter as a copy of the receiver.

  The
  new object contains copies of the receiver's MKNoteSenders and
  MKNoteReceivers.
*/
- copyWithZone: (NSZone *) zone;

/*!
  @return Returns an id.
  @brief Removes and frees the receiver's MKNoteSenders.

  Returns the receiver.
*/
- releaseNoteSenders;

/*!
  @return Returns an id.
  @brief Removes all the receiver's MKNoteSenders.

  Returns the receiver.
*/
- removeNoteSenders;

/*!
  @return Returns an MKNoteSender instance.
  @brief Returns the receiver's first MKNoteSender.

  This is method should
  only by invoked if the receiver only contains one MKNoteSender or if
  you don't care which MKNoteSender you get.  If there are currently
  no MKNoteSenders, this method creates and adds a MKNoteSender.
*/
- (MKNoteSender *) noteSender;

/*!
  @param  aNoteSender is an MKNoteSender instance.
  @return Returns an MKNoteSender instance.
  @brief Removes <i>aNoteSender</i> from its present owner (if any) and adds
  it to the receiver.

  Returns <i>aNoteSender</i>.  If the receiver is
  in performance, or if <i>aNoteSender</i> is already a member of the
  receiver, does nothing and returns <b>nil</b>.
*/
- (MKNoteSender *) addNoteSender: (MKNoteSender *) aNoteSender; 

/*!
  @param  aNoteSender is an MKNoteSender instance.
  @return Returns an MKNoteSender instance.
  @brief Removes aNoteSender from the receiver's NSArray of MKNoteSenders.

  
  Returns <i>aNoteSender</i>.  If the receiver is in a performance,
  does nothing and returns <b>nil</b>.
*/
- (MKNoteSender *) removeNoteSender: (MKNoteSender *) aNoteSender; 

/*!
  @brief Sends releaseNoteSenders to the receiver then releases the receivers ivars.

  
 */
- (void) dealloc; 

/* 
  You never send this message directly. Archives noteSender Array. 
 */
- (void) encodeWithCoder: (NSCoder *) aCoder;

- (id)initWithCoder:(NSCoder *)aDecoder;

@end

#endif