python - Issue with zope.component subscriber adapters adapting multiple objects -

given following code:

from zope.component import getglobalsitemanager, adapts, subscribers zope.interface import interface, implements   class a(object): pass class b(object): pass class c(b): pass  class ab(object):     implements(interface)     adapts(a, b)      def __init__(self, a, b):         pass  class ac(object):     implements(interface)     adapts(a, c)      def __init__(self, a, c):         pass  gsm = getglobalsitemanager() gsm.registersubscriptionadapter(ab) gsm.registersubscriptionadapter(ac)  = a() c = c()  adapter in subscribers([a, c], interface):     print adapter 

the output produces is:

<__main__.ab object @ 0xb242290> <__main__.ac object @ 0xb2422d0> 

why instance of ab returned? ab declares adapts , b. there way can achieve behavior ac returned?

you listing subscribers. subscribers notified of things implement interface(s) interested in.

c subclass of b, b subscriber interested, , notified. fact c implements little more of no concern b subscriber, object implement at least b interface.

subscribers generic, want objects implement interface or subclasses thereof. adapters more specific:

>>> gsm.registeradapter(ab) >>> gsm.registeradapter(ac) >>> zope.component import getadapters >>> adapter in getadapters((a, c), interface): ...     print adapter ...  (u'', <__main__.ac object @ 0x104b25a90>) 

getadapters() enumerates registered adapters, names:

>>> class anotherac(object): ...     implements(interface) ...     adapts(a, c) ...     def __init__(self, a, c): pass ...  >>> gsm.registeradapter(anotherac, name=u'another') >>> adapter in getadapters((a, c), interface): ...     print adapter ...  (u'', <__main__.ac object @ 0x104b25ed0>) (u'another', <__main__.anotherac object @ 0x104b25a90>)