843         

   843 # workflow extensions #########################################################

   844 

   845 class workflowable_definition(ybo.metadefinition):

   846     """extends default EntityType's metaclass to add workflow relations

   847     (i.e. in_state and wf_info_for).

   848     This is the default metaclass for WorkflowableEntityType

   849     """

   850     def __new__(mcs, name, bases, classdict):

   851         abstract = classdict.pop('abstract', False)

   852         defclass = super(workflowable_definition, mcs).__new__(mcs, name, bases, classdict)

   853         if not abstract:

   854             existing_rels = set(rdef.name for rdef in defclass.__relations__)

   855             if 'in_state' not in existing_rels and 'wf_info_for' not in existing_rels:

   856                 in_state = ybo.SubjectRelation('State', cardinality='1*',

   857                                                # XXX automatize this

   858                                                constraints=[RQLConstraint('S is ET, O state_of ET')],

   859                                                description=_('account state'))

   860                 yams_add_relation(defclass.__relations__, in_state, 'in_state')

   861                 wf_info_for = ybo.ObjectRelation('TrInfo', cardinality='1*', composite='object')

   862                 yams_add_relation(defclass.__relations__, wf_info_for, 'wf_info_for')

   863         return defclass

   864 

   865 class WorkflowableEntityType(ybo.EntityType):

   866     __metaclass__ = workflowable_definition

   867     abstract = True

   868     

   869 PyFileReader.context['WorkflowableEntityType'] = WorkflowableEntityType

   870