def getAdapterFactory(fromInterface, toInterface, default):
"""Return registered adapter for a given class and interface.
Note that is tied to the *Twisted* global registry, and will
thus not find adapters registered elsewhere.
"""
self = globalRegistry
if not isinstance(fromInterface, interface.InterfaceClass):
fromInterface = declarations.implementedBy(fromInterface)
factory = self.lookup1(fromInterface, toInterface)
if factory is None:
factory = default
return factory
def registerAdapter(adapterFactory, origInterface, *interfaceClasses):
"""Register an adapter class.
An adapter class is expected to implement the given interface, by
adapting instances implementing 'origInterface'. An adapter class's
__init__ method should accept one parameter, an instance implementing
'origInterface'.
"""
self = globalRegistry
assert interfaceClasses, "You need to pass an Interface"
global ALLOW_DUPLICATES
# deal with class->interface adapters:
if not isinstance(origInterface, interface.InterfaceClass):
origInterface = declarations.implementedBy(origInterface)
for interfaceClass in interfaceClasses:
factory = _registered(self, origInterface, interfaceClass)
if factory is not None and not ALLOW_DUPLICATES:
raise ValueError("an adapter (%s) was already registered." % (factory, ))
for interfaceClass in interfaceClasses:
self.register([origInterface], interfaceClass, '', adapterFactory)
def implementedBy(self, cls):
"""Test whether the specification is implemented by a class or factory.
Raise TypeError if argument is neither a class nor a callable."""
spec = implementedBy(cls)
return self in spec._implied
