spiff-arena/SpiffWorkflow/bpmn/specs/BpmnSpecMixin.py

# -*- coding: utf-8 -*-

# Copyright (C) 2012 Matthew Hampton
#
# This library 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 2.1 of the License, or (at your option) any later version.
#
# This library 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 this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301  USA

from ...task import TaskState
from ...operators import Operator
from ...specs.base import TaskSpec


class _BpmnCondition(Operator):

    def __init__(self, *args):
        if len(args) > 1:
            raise TypeError("Too many arguments")
        super(_BpmnCondition, self).__init__(*args)

    def _matches(self, task):
        return task.workflow.script_engine.evaluate(task, self.args[0])


class SequenceFlow(object):

    """
    Keeps information relating to a sequence flow
    """

    def __init__(self, id, name, documentation, target_task_spec):
        """
        Constructor.
        """
        self.id = id
        self.name = name.strip() if name else name
        self.documentation = documentation
        self.target_task_spec = target_task_spec

    def serialize(self):
        return {'id':self.id,
                'name':self.name,
                'documentation':self.documentation,
                'target_task_spec':self.target_task_spec.id}


class BpmnSpecMixin(TaskSpec):
    """
    All BPMN spec classes should mix this superclass in. It adds a number of
    methods that are BPMN specific to the TaskSpec.
    """

    def __init__(self, wf_spec, name, lane=None, position=None, **kwargs):
        """
        Constructor.

        :param lane: Indicates the name of the lane that this task belongs to
        (optional).
        """
        super(BpmnSpecMixin, self).__init__(wf_spec, name, **kwargs)
        self.outgoing_sequence_flows = {}
        self.outgoing_sequence_flows_by_id = {}
        self.lane = lane
        self.position = position or {'x': 0, 'y': 0}
        self.loopTask = False
        self.documentation = None
        self.data_input_associations = []
        self.data_output_associations = []

    @property
    def spec_type(self):
        return 'BPMN Task'

    def is_loop_task(self):
        """
        Returns true if this task is a BPMN looping task
        """
        return self.loopTask

    def connect_outgoing(self, taskspec, sequence_flow_id, sequence_flow_name,
                         documentation):
        """
        Connect this task spec to the indicated child.

        :param sequence_flow_id: The ID of the connecting sequenceFlow node.

        :param sequence_flow_name: The name of the connecting sequenceFlow
        node.
        """
        self.connect(taskspec)
        s = SequenceFlow(
            sequence_flow_id, sequence_flow_name, documentation, taskspec)
        self.outgoing_sequence_flows[taskspec.name] = s
        self.outgoing_sequence_flows_by_id[sequence_flow_id] = s

    def connect_outgoing_if(self, condition, taskspec, sequence_flow_id,
                            sequence_flow_name, documentation):
        """
        Connect this task spec to the indicated child, if the condition
        evaluates to true. This should only be called if the task has a
        connect_if method (e.g. ExclusiveGateway).

        :param sequence_flow_id: The ID of the connecting sequenceFlow node.

        :param sequence_flow_name: The name of the connecting sequenceFlow
        node.
        """
        self.connect_if(_BpmnCondition(condition), taskspec)
        s = SequenceFlow(
            sequence_flow_id, sequence_flow_name, documentation, taskspec)
        self.outgoing_sequence_flows[taskspec.name] = s
        self.outgoing_sequence_flows_by_id[sequence_flow_id] = s

    def get_outgoing_sequence_flow_by_spec(self, task_spec):
        """
        Returns the outgoing SequenceFlow targeting the specified task_spec.
        """
        return self.outgoing_sequence_flows[task_spec.name]

    def get_outgoing_sequence_flow_by_id(self, id):
        """
        Returns the outgoing SequenceFlow with the specified ID.
        """
        return self.outgoing_sequence_flows_by_id[id]

    def has_outgoing_sequence_flow(self, id):
        """
        Returns true if the SequenceFlow with the specified ID is leaving this
        task.
        """
        return id in self.outgoing_sequence_flows_by_id

    def get_outgoing_sequence_names(self):
        """
        Returns a list of the names of outgoing sequences. Some may be None.
        """
        return sorted([s.name for s in
                       list(self.outgoing_sequence_flows_by_id.values())])

    def get_outgoing_sequences(self):
        """
        Returns a list of outgoing sequences. Some may be None.
        """
        return iter(list(self.outgoing_sequence_flows_by_id.values()))

    # Hooks for Custom BPMN tasks ##########

    def entering_waiting_state(self, my_task):
        """
        Called when a task enters the WAITING state.

        A subclass may override this method to do work when this happens.
        """
        pass

    def entering_ready_state(self, my_task):
        """
        Called when a task enters the READY state.

        A subclass may override this method to do work when this happens.
        """
        pass

    def entering_complete_state(self, my_task):
        """
        Called when a task enters the COMPLETE state.

        A subclass may override this method to do work when this happens.
        """
        pass

    def entering_cancelled_state(self, my_task):
        """
        Called when a task enters the CANCELLED state.

        A subclass may override this method to do work when this happens.
        """
        pass

    def _on_ready_hook(self, my_task):
        super()._on_ready_hook(my_task)
        for obj in self.data_input_associations:
            obj.get(my_task)

    def _on_complete_hook(self, my_task):

        for obj in self.data_output_associations:
            obj.set(my_task)

        for obj in self.data_input_associations:
            # Remove the any copied input variables that might not have already been removed
            my_task.data.pop(obj.name, None)

        super(BpmnSpecMixin, self)._on_complete_hook(my_task)
        if isinstance(my_task.parent.task_spec, BpmnSpecMixin):
            my_task.parent.task_spec._child_complete_hook(my_task)
        if not my_task.workflow._is_busy_with_restore():
            self.entering_complete_state(my_task)

    def _child_complete_hook(self, child_task):
        pass

    def _on_cancel(self, my_task):
        super(BpmnSpecMixin, self)._on_cancel(my_task)
        my_task.workflow._task_cancelled_notify(my_task)
        if not my_task.workflow._is_busy_with_restore():
            self.entering_cancelled_state(my_task)

    def _update_hook(self, my_task):
        prev_state = my_task.state
        super(BpmnSpecMixin, self)._update_hook(my_task)
        if (prev_state != TaskState.WAITING and my_task.state == TaskState.WAITING and
                not my_task.workflow._is_busy_with_restore()):
            self.entering_waiting_state(my_task)

    def _on_ready_before_hook(self, my_task):
        super(BpmnSpecMixin, self)._on_ready_before_hook(my_task)
        if not my_task.workflow._is_busy_with_restore():
            self.entering_ready_state(my_task)