# Source code for taurus.core.evaluation.evaldevice

    #!/usr/bin/env python
    # ###########################################################################
    #
    # This file is part of Taurus
    #
    # http://taurus-scada.org
    #
    # Copyright 2011 CELLS / ALBA Synchrotron, Bellaterra, Spain
    #
    # Taurus is free software: you can redistribute it and/or modify
    # it under the terms of the GNU Lesser General Public License as published by
    # the Free Software Foundation, either version 3 of the License, or
    # (at your option) any later version.
    #
    # Taurus is distributed in the hope that it will be useful,
    # but WITHOUT ANY WARRANTY; without even the implied warranty of
    # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    # GNU Lesser General Public License for more details.
    #
    # You should have received a copy of the GNU Lesser General Public License
    # along with Taurus.  If not, see <http://www.gnu.org/licenses/>.
    #
    # ###########################################################################

    from taurus.core.taurusdevice import TaurusDevice
    from taurus.core.util.safeeval import SafeEvaluator
    from taurus.core.taurusbasetypes import TaurusDevState, TaurusAttrValue

    class EvaluationDevice(TaurusDevice, SafeEvaluator):
        """The evaluator object. It is a :class:`TaurusDevice` and is used as the
        parent of :class:`EvaluationAttribute` objects for which it performs the
        mathematical evaluation.

        .. seealso:: :mod:`taurus.core.evaluation`

        .. warning:: In most cases this class should not be instantiated directly.
                     Instead it should be done via the
                     :meth:`EvaluationFactory.getDevice`
        """

        _symbols = []
        # helper class property that stores a reference to the corresponding
        # factory
        _factory = None
        _scheme = "eval"

        def __init__(self, name="", **kw):
            """Object initialization."""
            self.call__init__(TaurusDevice, name, **kw)
            safedict = {}
            for s in self._symbols:
                if hasattr(self, s):
                    safedict[s] = getattr(self, s)
            SafeEvaluator.__init__(self, safedict=safedict)

        # -~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~
        # TaurusDevice necessary overwrite
        # -~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~
        def _createHWObject(self):
            return "Evaluation"

        # -~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~

        def getAttribute(self, attrname):
            """Returns the attribute object given its name"""
            full_attrname = "%s;%s" % (self.getFullName(), attrname)
            return self.factory().getAttribute(full_attrname)

        def decode(self, event_value):
            # TODO: Is this method ever called? (or maybe just garbage from 3.x?)
            if isinstance(event_value, int):  # TaurusSWDevState
                new_sw_state = event_value
            else:
                self.info("Unexpected value to decode: %s" % str(event_value))
                new_sw_state = TaurusDevState.NotReady
            value = TaurusAttrValue()
            value.rvalue = new_sw_state
            return value