- Add support for abtract python classes

- Create first modules: the Policy Python class


git-svn-id: svn://svn.gna.org/svn/sgpemv2/trunk@335 3ecf2c5c-341e-0410-92b4-d18e462d057c
This commit is contained in:
tchernobog 2006-02-16 22:50:32 +00:00
parent 5554ec2256
commit b6c49d98d6
6 changed files with 145 additions and 38 deletions

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@ -30,7 +30,6 @@
namespace sgpem namespace sgpem
{ {
class Policy; class Policy;
/** \brief /** \brief

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@ -27,8 +27,6 @@
namespace sgpem namespace sgpem
{ {
class PolicyManager; class PolicyManager;
class SG_DLLEXPORT PolicyManager class SG_DLLEXPORT PolicyManager
@ -36,10 +34,10 @@ namespace sgpem
public: public:
virtual ~PolicyManager() = 0; virtual ~PolicyManager() = 0;
virtual Policy* get_policy() = 0; virtual Policy& get_policy() = 0;
virtual void init() = 0; virtual void init() = 0;
}; };
} } //~ namespace sgpem
#endif #endif

94
src/pyloader/Abstract.py Normal file
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@ -0,0 +1,94 @@
class AbstractMethod (object):
"""Defines a class to create abstract methods
@example:
class Foo:
foo = AbstractMethod('foo')
"""
def __init__(self, func):
"""Constructor
@params func: name of the function (used when raising an
exception).
@type func: str
"""
self._function = func
def __get__(self, obj, type):
"""Get callable object
@returns An instance of AbstractMethodHelper.
This trickery is needed to get the name of the class for which
an abstract method was requested, otherwise it would be
sufficient to include a __call__ method in the AbstractMethod
class itself.
"""
return self.AbstractMethodHelper(self._function, type)
class AbstractMethodHelper (object):
"""Abstract method helper class
An AbstractMethodHelper instance is a callable object that
represents an abstract method.
"""
def __init__(self, func, cls):
self._function = func
self._class = cls
def __call__(self, *args, **kwargs):
"""Call abstract method
Raises a TypeError, because abstract methods can not be
called.
"""
raise TypeError('Abstract method `' + self._class.__name__ \
+ '.' + self._function + '\' called')
class Metaclass (type):
def __init__(cls, name, bases, *args, **kwargs):
"""Configure a new class
@param cls: Class object
@param name: Name of the class
@param bases: All base classes for cls
"""
super(Metaclass, cls).__init__(cls, name, bases, *args, **kwargs)
# Detach cls.new() from class Metaclass, and make it a method
# of cls.
cls.__new__ = staticmethod(cls.new)
# Find all abstract methods, and assign the resulting list to
# cls.__abstractmethods__, so we can read that variable when a
# request for allocation (__new__) is done.
abstractmethods = []
ancestors = list(cls.__mro__)
ancestors.reverse() # Start with __builtin__.object
for ancestor in ancestors:
for clsname, clst in ancestor.__dict__.items():
if isinstance(clst, AbstractMethod):
abstractmethods.append(clsname)
else:
if clsname in abstractmethods:
abstractmethods.remove(clsname)
abstractmethods.sort()
setattr(cls, '__abstractmethods__', abstractmethods)
def new(self, cls):
"""Allocator for class cls
@param self: Class object for which an instance should be
created.
@param cls: Same as self.
"""
if len(cls.__abstractmethods__):
raise NotImplementedError('Can\'t instantiate class `' + \
cls.__name__ + '\';\n' + \
'Abstract methods: ' + \
", ".join(cls.__abstractmethods__))
return object.__new__(self)

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@ -54,4 +54,5 @@ libpyloader_la_SOURCES = \
noinst_HEADERS = python_policy.hh \ noinst_HEADERS = python_policy.hh \
python_policy_manager.hh python_policy_manager.hh
mod_PYTHON = Abstract.py \
Policy.py

15
src/pyloader/Policy.py Normal file
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@ -0,0 +1,15 @@
''' from sgpem import SchedulableQueue, PolicyParameters '''
from Abstract import *
class Policy:
'''
Avoid instantiation of an abstract class.
'''
__metaclass__ = Metaclass
configure = AbstractMethod('configure')
sort_queue = AbstractMethod('sort_queue')
is_preemptive = AbstractMethod('is_preemptive')
is_time_sliced = AbstractMethod('is_time_sliced')
get_parameters = AbstractMethod('get_parameters')