Port everything to work with Python 2.6 and (hopefully) 3.0.

Phew, this was harder than I expected, mostly because I 
noticed I never grokked metaclasses all that well. Now it's 
slightly better ;-).



git-svn-id: svn://svn.gna.org/svn/sgpemv2/trunk@1344 3ecf2c5c-341e-0410-92b4-d18e462d057c

plugins/pyloader/src/CPUPolicy.py

@@ -1,17 +1,11 @@
-from Abstract import *
+from abc import *
 import sgpem
                 
-## @brief This is the abstract class a user-defined policy
-# should inherit from
-#
-# This class also exposes the method sort(), which can be
-# used to easily sort the queue of ready process with a
-# user-defined given compare function.
-class CPUPolicy:
-    ## @var Avoid instantiation of an abstract class.
-    # @see Abstract.Metaclass
-    __metaclass__ = Metaclass
-
+## @brief The abstract base class needed for compatibility between 
+# Python 2.6 and Python 3.x.
+#  
+# @see CPUPolicy
+class CPUPolicyBase(object):
     ## @brief Configure policy to initial values
     #
     # This is called just before a simulation starts, and is responsible
@@ -26,7 +20,9 @@ class CPUPolicy:
     # @endcode
     #
     # @see sgpem::Policy::get_parameters()
-    configure = AbstractMethod('configure')
+    @abstractmethod
+    def configure(self):
+        pass
 
     ## @brief Sort ready processes queue
     #
@@ -46,7 +42,9 @@ class CPUPolicy:
     # swap(positionA, positionB) and size().
     #
     # @see Policy::Policy::sort()
-    sort_queue = AbstractMethod('sort_queue')
+    @abstractmethod
+    def sort_queue(self, queue):
+        pass
 
     ## @brief Returns whether the policy wants to be preemptive,
     # other than by normal time slice termination
@@ -70,7 +68,9 @@ class CPUPolicy:
     # slice (or a process blocking/termination, of course) before
     # selecting a new running process, even if it has greater priority
     # than the current one
-    is_preemptive = AbstractMethod('is_preemptive')
+    @abstractmethod
+    def is_preemptive(self):
+        pass
 
     ## @brief Returns how long is a time-slice for this policy
     #
@@ -90,7 +90,9 @@ class CPUPolicy:
     #
     # @return -1 If the policy doesn't want to use time slices
     # @return 0+ To specify a time slice duration for this policy
-    get_time_slice = AbstractMethod('get_time_slice')
+    @abstractmethod
+    def get_time_slice(self):
+        pass
     
     ## @brief Returns the PolicyParameters instance you can use in
     # Policy::Policy::configure()
@@ -178,3 +180,18 @@ class CPUPolicy:
         # puts pivot in place
         queue.swap(i,b)
         return i
+
+
+        
+## @brief This is the abstract class a user-defined policy
+# should inherit from
+#
+# This class also exposes the method sort(), which can be
+# used to easily sort the queue of ready process with a
+# user-defined given compare function.
+#
+# @see CPUPolicyBase
+CPUPolicy = ABCMeta('CPUPolicy', (CPUPolicyBase, ), {})
+
+
+print (dir (CPUPolicy))