import tuned.logs
import os
__all__ = ["ClassLoader"]
log = tuned.logs.get()
class ClassLoader(object):
__slots__ = ["_namespace", "_prefix", "_interface"]
def _set_loader_parameters(self):
"""
This method has to be implemented in child class and should
set _namespace, _prefix, and _interface member attributes.
"""
raise NotImplementedError()
def __init__(self):
super(ClassLoader, self).__init__()
self._namespace = None
self._prefix = None
self._interface = None
self._set_loader_parameters()
assert type(self._namespace) is str
assert type(self._prefix) is str
assert type(self._interface) is type and issubclass(self._interface, object)
def load_class(self, class_name):
assert type(class_name) is str
module_name = "%s.%s%s" % (self._namespace, self._prefix, class_name)
return self._get_class(module_name)
def _get_class(self, module_name):
log.debug("loading module %s" % module_name)
module = __import__(module_name)
path = module_name.split(".")
path.pop(0)
while len(path) > 0:
module = getattr(module, path.pop(0))
for name in module.__dict__:
cls = getattr(module, name)
if type(cls) is type and issubclass(cls, self._interface):
return cls
raise ImportError("Cannot find the class %s." % module_name)
def load_all_classes(self):
package = __import__(self._namespace)
basename = self._namespace.split(".")[-1]
classes = []
for module_name in os.listdir(getattr(package, basename).__path__[0]):
try:
module_name = os.path.splitext(module_name)[0]
if not module_name.startswith(self._prefix):
continue
next_class = self._get_class(
"%s.%s" % (self._namespace, module_name)
)
if next_class not in classes:
classes.append(next_class)
except ImportError:
pass
return classes
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