/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * The contents of this file are subject to the Netscape Public
 * 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 License at http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s): 
 */

#include "nsISupports.idl"
#include "nsIRDFResource.idl"
#include "nsIRDFNode.idl"

// An nsIRDFObserver object is an observer that will be notified
// when assertions are made or removed from a datasource
[scriptable, uuid(3CC75360-484A-11D2-BC16-00805F912FE7)]
interface nsIRDFObserver : nsISupports {
    // This method is called whenever a new assertion is made
    // in the data source
    void OnAssert(in nsIRDFResource aSource,
                  in nsIRDFResource aProperty,
                  in nsIRDFNode     aTarget);

    // This method is called whenever an assertion is removed
    // from the data source
    void OnUnassert(in nsIRDFResource aSource,
                    in nsIRDFResource aProperty,
                    in nsIRDFNode     aTarget);

    void OnChange(in nsIRDFResource aSource,
                  in nsIRDFResource aProperty,
                  in nsIRDFNode     aOldTarget,
                  in nsIRDFNode     aNewTarget);

    void OnMove(in nsIRDFResource aOldSource,
                in nsIRDFResource aNewSource,
                in nsIRDFResource aProperty,
                in nsIRDFNode     aTarget);
};