self.cache_manager = manager

        Query.__init__(self, *args, **kw)

    def __iter__(self):

        """override __iter__ to pull results from Beaker

           if particular attributes have been configured.

           Note that this approach does *not* detach the loaded objects from

           the current session. If the cache backend is an in-process cache

           (like "memory") and lives beyond the scope of the current session's

           transaction, those objects may be expired. The method here can be

           modified to first expunge() each loaded item from the current

           session before returning the list of items, so that the items

           in the cache are not the same ones in the current Session.

        """

        if hasattr(self, '_cache_parameters'):

            return self.get_value(createfunc=lambda:

                                  list(Query.__iter__(self)))

        else:

            return Query.__iter__(self)

    def invalidate(self):

        """Invalidate the value represented by this Query."""

        cache, cache_key = _get_cache_parameters(self)

        cache.remove(cache_key)

    def get_value(self, merge=True, createfunc=None):

        """Return the value from the cache for this query.

        Raise KeyError if no value present and no

        createfunc specified.

        """

        cache, cache_key = _get_cache_parameters(self)

        ret = cache.get_value(cache_key, createfunc=createfunc)

        if merge:

            ret = self.merge_result(ret, load=False)

        return ret

    def set_value(self, value):

        """Set the value in the cache for this query."""

        cache, cache_key = _get_cache_parameters(self)

        cache.put(cache_key, value)

    def query(*arg, **kw):

    return query

def get_cache_region(name, region):

    if region not in beaker.cache.cache_regions:

        raise BeakerException('Cache region `%s` not configured '

            'Check if proper cache settings are in the .ini files' % region)

    kw = beaker.cache.cache_regions[region]

    return beaker.cache.Cache._get_cache(name, kw)

def _get_cache_parameters(query):

    """For a query with cache_region and cache_namespace configured,

    return the correspoinding Cache instance and cache key, based

    on this query's current criterion and parameter values.

    """

    if not hasattr(query, '_cache_parameters'):

        raise ValueError("This Query does not have caching "

                         "parameters configured.")

    region, namespace, cache_key = query._cache_parameters

    namespace = _namespace_from_query(namespace, query)

    if cache_key is None:

        # cache key - the value arguments from this query's parameters.

        args = _params_from_query(query)

        cache_key = " ".join([str(x) for x in args])

    # get cache

    #cache = query.cache_manager.get_cache_region(namespace, region)

    cache = get_cache_region(namespace, region)

    # optional - hash the cache_key too for consistent length

    # import uuid

    # cache_key= str(uuid.uuid5(uuid.NAMESPACE_DNS, cache_key))

    return cache, cache_key

def _namespace_from_query(namespace, query):

    # cache namespace - the token handed in by the

    # option + class we're querying against

    namespace = " ".join([namespace] + [str(x) for x in query._entities])

    # memcached wants this

    namespace = namespace.replace(' ', '_')

        self.region = region

        self.namespace = namespace

        self._relationship_options = {

            (attribute.property.parent.class_, attribute.property.key): self

        }

    def process_query_conditionally(self, query):

        """Process a Query that is used within a lazy loader.

        (the process_query_conditionally() method is a SQLAlchemy

        hook invoked only within lazyload.)

        """

        if query._current_path:

            mapper, key = query._current_path[-2:]

            for cls in mapper.class_.__mro__:

                if (cls, key) in self._relationship_options:

                    relationship_option = \

                        self._relationship_options[(cls, key)]

                    _set_cache_parameters(

                            query,

                            relationship_option.region,

                            relationship_option.namespace,

                            None)

    def and_(self, option):

        """Chain another RelationshipCache option to this one.

        While many RelationshipCache objects can be specified on a single

        Query separately, chaining them together allows for a more efficient

        lookup during load.

        """

        self._relationship_options.update(option._relationship_options)

        return self

def _params_from_query(query):

    """Pull the bind parameter values from a query.

    This takes into account any scalar attribute bindparam set up.

    E.g. params_from_query(query.filter(Cls.foo==5).filter(Cls.bar==7)))

    would return [5, 7].

    """

    v = []

    def visit_bindparam(bind):

        value = query._params.get(bind.key, bind.value)

        # lazyloader may dig a callable in here, intended

        # to late-evaluate params after autoflush is called.

        # convert to a scalar value.

        if callable(value):

            value = value()

        v.append(value)

    if query._criterion is not None:

    return v