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# Source code for camelot.core.orm

    #  ============================================================================
    #
    #  Copyright (C) 2007-2011 Conceptive Engineering bvba. All rights reserved.
    #  www.conceptive.be / project-camelot@conceptive.be
    #
    #  This file is part of the Camelot Library.
    #
    #  This file may be used under the terms of the GNU General Public
    #  License version 2.0 as published by the Free Software Foundation
    #  and appearing in the file license.txt included in the packaging of
    #  this file.  Please review this information to ensure GNU
    #  General Public Licensing requirements will be met.
    #
    #  If you are unsure which license is appropriate for your use, please
    #  visit www.python-camelot.com or contact project-camelot@conceptive.be
    #
    #  This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
    #  WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
    #
    #  For use of this library in commercial applications, please contact
    #  project-camelot@conceptive.be
    #
    #  ============================================================================

    """Helper functions related to the connection between the SQLAlchemy
    ORM and the Camelot Views.
    """

    import logging
    logger = logging.getLogger('camelot.core.orm')

    def refresh_session(session):
        """Session refresh expires all objects in the current session and sends
        a local entity update signal via the remote_signals mechanism

        this method ought to be called in the model thread.
        """
        from camelot.view.remote_signals import get_signal_handler
        import sqlalchemy.exc as sa_exc
        logger.debug('session refresh requested')
        signal_handler = get_signal_handler()
        refreshed_objects = []
        expunged_objects = []
        for _key, obj in session.identity_map.items():
            try:
                session.refresh( obj )
                refreshed_objects.append( obj )
            except sa_exc.InvalidRequestError:
                #
                # this object could not be refreshed, it was probably deleted
                # outside the scope of this session, so assume it is deleted
                # from the application its point of view
                #
                session.expunge( obj )
                expunged_objects.append( obj )
        for obj in refreshed_objects:
            signal_handler.sendEntityUpdate( None, obj )
        for obj in expunged_objects:
            signal_handler.sendEntityDelete( None, obj )
        return refreshed_objects

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