[Zope3-checkins] CVS: Zope3/src/zope/interface - surrogate.py:1.6

[Ken Manheimer]

Update of /cvs-repository/Zope3/src/zope/interface
In directory cvs.zope.org:/tmp/cvs-serv18566

Modified Files:
	surrogate.py 
Log Message:
.queryFactory(): enables you to get an adapter, or check for the
existence of one, given just the type of the thing.

Derived from .queryAdapter(), including tests.


=== Zope3/src/zope/interface/surrogate.py 1.5 => 1.6 ===
--- Zope3/src/zope/interface/surrogate.py:1.5	Sun Feb 15 08:04:26 2004
+++ Zope3/src/zope/interface/surrogate.py	Tue Mar  2 17:56:54 2004
@@ -353,6 +353,75 @@
         return default
 
 
+    def queryFactory(self, declaration, interface, default=None):
+        """Query for factory that adapts type-declaration things to interface.
+
+           This enables you to get an adapter, and/or check for the existence
+           of one, given just the type (interface) of a thing.
+
+           >>> import zope.interface
+           >>> from zope.interface import implementedBy
+           >>> class F0(zope.interface.Interface):
+           ...     pass
+           >>> class F1(F0):
+           ...     pass
+
+           >>> class C:
+           ...     zope.interface.implements(F1)
+           >>> c = C()
+
+           >>> registry = SurrogateRegistry()
+
+           Adapting to some other interface for which there is no
+           adapter returns the default:
+
+           >>> class B0(zope.interface.Interface):
+           ...     pass
+           >>> class B1(B0):
+           ...     pass
+
+           >>> registry.queryFactory(F1, B0)
+           >>> registry.queryFactory(F1, B0, 42)
+           42
+
+           Unless we define an adapter:
+
+           >>> def f1(ob):
+           ...     return 1
+
+           >>> registry.provideAdapter(F0, B1, [f1])
+           >>> registry.queryFactory(F1, B0) == [f1]
+           True
+
+           If we define a more specific adapter (for F1), we'll get that:
+
+           >>> def f2(ob):
+           ...     return 2
+
+           >>> registry.provideAdapter(F1, B1, [f2])
+           >>> registry.queryFactory(F1, B0) == [f2]
+           True
+
+           >>> def f3(ob):
+           ...     return 3
+
+           >>> registry.provideAdapter(F1, B0, [f3])
+           >>> registry.queryFactory(F1, B0) == [f3]
+           True
+           """
+
+        s = self.get(declaration)
+
+        factories = s.get((False, interface))
+        if factories is None:
+            factories = self._default.get((False, interface))
+
+        if factories is not None:
+            return factories
+
+        return default
+
+
     def querySubscriptionAdapter(self, ob, interface, name=u'', default=(),
                             raw=False):
         """Query for subscription adapters