L2SS-271: Make hardware_device and statistics device proper ABCs.

devices/devices/hardware_device.py

@@ -11,8 +11,10 @@
 
 """
 
+from abc import ABCMeta, abstractmethod
+
 # PyTango imports
-from tango.server import Device, command
+from tango.server import Device, command, DeviceMeta
 from tango import DevState, DebugIt
 # Additional import
 
@@ -26,8 +28,12 @@ from devices.device_decorators import only_in_states, fault_on_error
 import logging
 logger = logging.getLogger()
 
+class AbstractDeviceMetas(DeviceMeta, ABCMeta):
+    ''' Collects meta classes to allow hardware_device to be both a Device and an ABC. '''
+    pass
+
 #@log_exceptions()
-class hardware_device(Device):
+class hardware_device(Device, metaclass=AbstractDeviceMetas):
     """
 
     **Properties:**
@@ -155,13 +161,18 @@ class hardware_device(Device):
         self.set_state(DevState.FAULT)
 
 
-    # functions that can be overloaded
+    # functions that can or must be overloaded
     def configure_for_fault(self):
         pass
+
+    @abstractmethod
     def configure_for_off(self):
         pass
+
     def configure_for_on(self):
         pass
+
+    @abstractmethod
     def configure_for_initialise(self):
         pass
 

devices/devices/sdp/statistics.py

@@ -18,6 +18,8 @@ parentdir = os.path.dirname(currentdir)
 parentdir = os.path.dirname(parentdir)
 sys.path.append(parentdir)
 
+from abc import ABCMeta, abstractmethod
+
 # PyTango imports
 from tango.server import run
 from tango.server import device_property, attribute
@@ -37,10 +39,13 @@ import numpy
 
 __all__ = ["Statistics"]
 
-class Statistics(hardware_device):
+class Statistics(hardware_device, metaclass=ABCMeta):
 
     # In derived classes, set this to a subclass of StatisticsCollector
-    STATISTICS_COLLECTOR_CLASS = NotImplementedError
+    @property
+    @abstractmethod
+    def STATISTICS_COLLECTOR_CLASS(self):
+        pass
 
     # -----------------
     # Device Properties