/*************************************************************************
 *
 *  $RCSfile: XAggregation.idl,v $
 *
 *  $Revision: 1.7 $
 *
 *  last change: $Author: jsc $ $Date: 2001/03/16 15:10:43 $
 *
 *  The Contents of this file are made available subject to the terms of
 *  either of the following licenses
 *
 *         - GNU Lesser General Public License Version 2.1
 *         - Sun Industry Standards Source License Version 1.1
 *
 *  Sun Microsystems Inc., October, 2000
 *
 *  GNU Lesser General Public License Version 2.1
 *  =============================================
 *  Copyright 2000 by Sun Microsystems, Inc.
 *  901 San Antonio Road, Palo Alto, CA 94303, USA
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
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 *  Lesser General Public License for more details.
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 *  You should have received a copy of the GNU Lesser General Public
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 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA  02111-1307  USA
 *
 *
 *  Sun Industry Standards Source License Version 1.1
 *  =================================================
 *  The contents of this file are subject to the Sun Industry Standards
 *  Source License Version 1.1 (the "License"); You may not use this file
 *  except in compliance with the License. You may obtain a copy of the
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 *  See the License for the specific provisions governing your rights and
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 ************************************************************************/
#ifndef __com_sun_star_uno_XAggregation_idl__
#define __com_sun_star_uno_XAggregation_idl__

#ifndef __com_sun_star_uno_XInterface_idl__
#include <com/sun/star/uno/XInterface.idl>
#endif

#ifndef __com_sun_star_uno_Uik_idl__
#include <com/sun/star/uno/Uik.idl>
#endif


//=============================================================================

module com { module sun { module star { module uno { 

//=============================================================================
/** Objects which implement this interface can become aggregates of
	a delegator.
	
	<p>That means if an object "A" aggregates "B", "A" can provide all
	or some of the interfaces of "B". Whenever the method
	<member>XInterface::queryInterface()</member>
	is called on either of the objects, the call will be forwarded
	to object "A". Object "A" now can determine whether to use the
	interfaces of "A" or "B" or neither. Actually, any number of 
	aggregates can be used, even nested ones (aggregated objects which are
	delegators by themselves).
	
	<p>The following rules are to be observed:
	<ol>
	<li>All calls to <member>XInterface::acquire()</member>
	which are made before the delegator was set (using the method
	<member>XAggregation::setDelegator()</member>) must not be taken back 
	(using the method <member>XInterface::release()</member>)
	before the delegation is removed by calling
	<code>xAggregation-&gt;setDelegator(NULL)</code>.
	
	<li>The constructor of a delegator has to increment its 
	own reference count by calling its method 
	<member>XInterface::acquire()</member>
	before it sets itself to any aggregate using the method
	<member>XAggregation::setDelegator()</member>. After that
	call it has to reset its own reference count without the 
	destructor getting called.
	
	<li>The destructor of a delegator has to reset the delegator in
	its aggregated objects by calling their method
	<member>XAggregation::setDelegator()</member> with 
	<const>NULL</const> before it releases its reference to 
	its aggregated objects.
	</ol>
*/
interface XAggregation: com::sun::star::uno::XInterface
{
	//-------------------------------------------------------------------------
	/** sets the object to which all calls to the method
		<member>XInterface::queryInterface()</member>
		have to be forwarded. @
		
		@param xDelegator
		specifies the object which handles the calls to 
		<member>XInterface::queryInterface()</member>. 
		If <var>xDelegator</var> is <const>NULL</const>, the delegator is 
		removed and thus the object becomes its own delegator and has 
		to handle calls to the method
		<member>XInterface::queryInterface()</member>
		itself.
		
		@example:Java
		
		<listing>
		
		void setDelegator( com.sun.star.uno.XInterface aDelegator )
		{
		pDelegator =aDelegator;
		}
		
		
		com.sun.star.uno.XInterface queryInterface( com.sun.star.uno.Uik aUik )
		{
		com.sun.star.uno.XInterface pRet = null;
		
		// pDelegator may be already set 
		if( pDelegator == null )
		pRet = queryAggregation( aIFace );
		else
		pRet = pDelegator->queryInterface( aIFace );
		return pRet;
		}
		
		</listing>
		
		@see XAggregation::queryAggregation
	*/
	void setDelegator( [in] com::sun::star::uno::XInterface pDelegator );

	//-------------------------------------------------------------------------
	/** is similar to <member>XInterface::queryInterface()</member>,
		but it is to be processed directly without being forwarded to the 
		delegator. @
		
		<p>This method is only called from within an implementation of         
		<member>XInterface::queryInterface()</member> 
		or <member>XAggregation::queryAggregation()</member>. This method
		is to be called by the delegator if it does not implement the
		interface itself. An object which got aggregated cannot depend
		on getting its own interface when it calls the method
		<member>XInterface::queryInterface()</member>.
		
		@example:Java
		
		<listing>
		
		Class queryAggregation( Class aIFace )
		{
		// The Uno-System provides information about their own interfaces
		Class pRet = Uno.getInterface( this, aIFace );
		
		if( pRet == null )
		// not an own interface, thus forward to the aggregated object
		pRet = aMyAggObj->queryAggregation( aIface );
		return pRet;
		}
		
		</listing>
		
		@see XAggregation::setDelegator
	*/
	any queryAggregation( [in] type aType );
//	boolean queryAggregation( [in] com::sun::star::uno::Uik aUik,
//			 [out] any ifc );

};

//=============================================================================

}; }; }; }; 

#endif
