Merge pull request #189 from zopefoundation/issue136-issue134

Documentation clarifications.
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Jason Madden 2020-03-18 11:59:47 -05:00 committed by GitHub
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2 changed files with 151 additions and 141 deletions

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@ -24,27 +24,27 @@ Let's look at a simple example, using a single required specification:
>>> from zope.interface.adapter import AdapterRegistry
>>> import zope.interface
>>> class IRequire1(zope.interface.Interface):
>>> class IRequireBase(zope.interface.Interface):
... pass
>>> class IProvide1(zope.interface.Interface):
>>> class IProvideBase(zope.interface.Interface):
... pass
>>> class IProvide2(IProvide1):
>>> class IProvideChild(IProvideBase):
... pass
>>> registry = AdapterRegistry()
We'll register an object that depends on ``IRequire1`` and "provides" ``IProvide2``:
We'll register an object that depends on ``IRequireBase`` and "provides" ``IProvideChild``:
.. doctest::
>>> registry.register([IRequire1], IProvide2, '', 12)
>>> registry.register([IRequireBase], IProvideChild, '', 'Base->Child')
Given the registration, we can look it up again:
.. doctest::
>>> registry.lookup([IRequire1], IProvide2, '')
12
>>> registry.lookup([IRequireBase], IProvideChild, '')
'Base->Child'
Note that we used an integer in the example. In real applications,
one would use some objects that actually depend on or provide
@ -58,21 +58,21 @@ specification that extends the specification that it depends on:
.. doctest::
>>> class IRequire2(IRequire1):
>>> class IRequireChild(IRequireBase):
... pass
>>> registry.lookup([IRequire2], IProvide2, '')
12
>>> registry.lookup([IRequireChild], IProvideChild, '')
'Base->Child'
We can use a class implementation specification to look up the object:
.. doctest::
>>> @zope.interface.implementer(IRequire2)
>>> @zope.interface.implementer(IRequireChild)
... class C2:
... pass
>>> registry.lookup([zope.interface.implementedBy(C2)], IProvide2, '')
12
>>> registry.lookup([zope.interface.implementedBy(C2)], IProvideChild, '')
'Base->Child'
and it can be looked up for interfaces that its provided interface
@ -80,23 +80,23 @@ extends:
.. doctest::
>>> registry.lookup([IRequire1], IProvide1, '')
12
>>> registry.lookup([IRequire2], IProvide1, '')
12
>>> registry.lookup([IRequireBase], IProvideBase, '')
'Base->Child'
>>> registry.lookup([IRequireChild], IProvideBase, '')
'Base->Child'
But if you require a specification that doesn't extend the specification the
object depends on, you won't get anything:
.. doctest::
>>> registry.lookup([zope.interface.Interface], IProvide1, '')
>>> registry.lookup([zope.interface.Interface], IProvideBase, '')
By the way, you can pass a default value to lookup:
.. doctest::
>>> registry.lookup([zope.interface.Interface], IProvide1, '', 42)
>>> registry.lookup([zope.interface.Interface], IProvideBase, '', 42)
42
If you try to get an interface the object doesn't provide, you also
@ -104,47 +104,47 @@ won't get anything:
.. doctest::
>>> class IProvide3(IProvide2):
>>> class IProvideGrandchild(IProvideChild):
... pass
>>> registry.lookup([IRequire1], IProvide3, '')
>>> registry.lookup([IRequireBase], IProvideGrandchild, '')
You also won't get anything if you use the wrong name:
.. doctest::
>>> registry.lookup([IRequire1], IProvide1, 'bob')
>>> registry.register([IRequire1], IProvide2, 'bob', "Bob's 12")
>>> registry.lookup([IRequire1], IProvide1, 'bob')
>>> registry.lookup([IRequireBase], IProvideBase, 'bob')
>>> registry.register([IRequireBase], IProvideChild, 'bob', "Bob's 12")
>>> registry.lookup([IRequireBase], IProvideBase, 'bob')
"Bob's 12"
You can leave the name off when doing a lookup:
.. doctest::
>>> registry.lookup([IRequire1], IProvide1)
12
>>> registry.lookup([IRequireBase], IProvideBase)
'Base->Child'
If we register an object that provides ``IProvide1``:
If we register an object that provides ``IProvideBase``:
.. doctest::
>>> registry.register([IRequire1], IProvide1, '', 11)
>>> registry.register([IRequireBase], IProvideBase, '', 'Base->Base')
then that object will be prefered over ``O(12)``:
then that object will be prefered over ``O('Base->Child')``:
.. doctest::
>>> registry.lookup([IRequire1], IProvide1, '')
11
>>> registry.lookup([IRequireBase], IProvideBase, '')
'Base->Base'
Also, if we register an object for ``IRequire2``, then that will be preferred
when using ``IRequire2``:
Also, if we register an object for ``IRequireChild``, then that will be preferred
when using ``IRequireChild``:
.. doctest::
>>> registry.register([IRequire2], IProvide1, '', 21)
>>> registry.lookup([IRequire2], IProvide1, '')
21
>>> registry.register([IRequireChild], IProvideBase, '', 'Child->Base')
>>> registry.lookup([IRequireChild], IProvideBase, '')
'Child->Base'
Finding out what, if anything, is registered
--------------------------------------------
@ -155,20 +155,20 @@ exact match:
.. doctest::
>>> print(registry.registered([IRequire1], IProvide1))
11
>>> print(registry.registered([IRequireBase], IProvideBase))
Base->Base
>>> print(registry.registered([IRequire1], IProvide2))
12
>>> print(registry.registered([IRequireBase], IProvideChild))
Base->Child
>>> print(registry.registered([IRequire1], IProvide2, 'bob'))
>>> print(registry.registered([IRequireBase], IProvideChild, 'bob'))
Bob's 12
>>> print(registry.registered([IRequire2], IProvide1))
21
>>> print(registry.registered([IRequireChild], IProvideBase))
Child->Base
>>> print(registry.registered([IRequire2], IProvide2))
>>> print(registry.registered([IRequireChild], IProvideChild))
None
In the last example, ``None`` was returned because nothing was registered
@ -182,10 +182,10 @@ version of lookup that takes a single required interface:
.. doctest::
>>> registry.lookup1(IRequire2, IProvide1, '')
21
>>> registry.lookup1(IRequire2, IProvide1)
21
>>> registry.lookup1(IRequireChild, IProvideBase, '')
'Child->Base'
>>> registry.lookup1(IRequireChild, IProvideBase)
'Child->Base'
Actual Adaptation
-----------------
@ -205,12 +205,12 @@ factories:
... class X(object):
... pass
>>> @zope.interface.implementer(IProvide1)
>>> @zope.interface.implementer(IProvideBase)
... class Y(object):
... def __init__(self, context):
... self.context = context
>>> registry.register([IR], IProvide1, '', Y)
>>> registry.register([IR], IProvideBase, '', Y)
In this case, we registered a class as the factory. Now we can call
``queryAdapter`` to get the adapted object:
@ -218,7 +218,7 @@ In this case, we registered a class as the factory. Now we can call
.. doctest::
>>> x = X()
>>> y = registry.queryAdapter(x, IProvide1)
>>> y = registry.queryAdapter(x, IProvideBase)
>>> y.__class__.__name__
'Y'
>>> y.context is x
@ -231,8 +231,8 @@ We can register and lookup by name too:
>>> class Y2(Y):
... pass
>>> registry.register([IR], IProvide1, 'bob', Y2)
>>> y = registry.queryAdapter(x, IProvide1, 'bob')
>>> registry.register([IR], IProvideBase, 'bob', Y2)
>>> y = registry.queryAdapter(x, IProvideBase, 'bob')
>>> y.__class__.__name__
'Y2'
>>> y.context is x
@ -251,10 +251,10 @@ Passing ``super`` objects works as expected to find less specific adapters:
... def query_next(self):
... return registry.queryAdapter(
... super(type(self.context), self.context),
... IProvide1)
>>> registry.register([IDerived], IProvide1, '', DerivedAdapter)
... IProvideBase)
>>> registry.register([IDerived], IProvideBase, '', DerivedAdapter)
>>> derived = Derived()
>>> adapter = registry.queryAdapter(derived, IProvide1)
>>> adapter = registry.queryAdapter(derived, IProvideBase)
>>> adapter.__class__.__name__
'DerivedAdapter'
>>> adapter = adapter.query_next()
@ -277,14 +277,14 @@ the state of the object being adapted:
... class Object(object):
... name = 'object'
>>> registry.register([IR], IProvide1, 'conditional', factory)
>>> registry.register([IR], IProvideBase, 'conditional', factory)
>>> obj = Object()
>>> registry.queryAdapter(obj, IProvide1, 'conditional')
>>> registry.queryAdapter(obj, IProvideBase, 'conditional')
'adapter'
>>> obj.name = 'no object'
>>> registry.queryAdapter(obj, IProvide1, 'conditional') is None
>>> registry.queryAdapter(obj, IProvideBase, 'conditional') is None
True
>>> registry.queryAdapter(obj, IProvide1, 'conditional', 'default')
>>> registry.queryAdapter(obj, IProvideBase, 'conditional', 'default')
'default'
An alternate method that provides the same function as ``queryAdapter()`` is
@ -292,12 +292,12 @@ An alternate method that provides the same function as ``queryAdapter()`` is
.. doctest::
>>> y = registry.adapter_hook(IProvide1, x)
>>> y = registry.adapter_hook(IProvideBase, x)
>>> y.__class__.__name__
'Y'
>>> y.context is x
True
>>> y = registry.adapter_hook(IProvide1, x, 'bob')
>>> y = registry.adapter_hook(IProvideBase, x, 'bob')
>>> y.__class__.__name__
'Y2'
>>> y.context is x
@ -316,7 +316,7 @@ For that, provide ``None`` as the required interface:
.. doctest::
>>> registry.register([None], IProvide1, '', 1)
>>> registry.register([None], IProvideBase, '', 1)
then we can use that adapter for interfaces we don't have specific
adapters for:
@ -325,15 +325,15 @@ adapters for:
>>> class IQ(zope.interface.Interface):
... pass
>>> registry.lookup([IQ], IProvide1, '')
>>> registry.lookup([IQ], IProvideBase, '')
1
Of course, specific adapters are still used when applicable:
.. doctest::
>>> registry.lookup([IRequire2], IProvide1, '')
21
>>> registry.lookup([IRequireChild], IProvideBase, '')
'Child->Base'
Class adapters
@ -344,8 +344,8 @@ same as registering them for a class:
.. doctest::
>>> registry.register([zope.interface.implementedBy(C2)], IProvide1, '', 'C21')
>>> registry.lookup([zope.interface.implementedBy(C2)], IProvide1, '')
>>> registry.register([zope.interface.implementedBy(C2)], IProvideBase, '', 'C21')
>>> registry.lookup([zope.interface.implementedBy(C2)], IProvideBase, '')
'C21'
Dict adapters
@ -368,9 +368,9 @@ You can unregister by registering ``None``, rather than an object:
.. doctest::
>>> registry.register([zope.interface.implementedBy(C2)], IProvide1, '', None)
>>> registry.lookup([zope.interface.implementedBy(C2)], IProvide1, '')
21
>>> registry.register([zope.interface.implementedBy(C2)], IProvideBase, '', None)
>>> registry.lookup([zope.interface.implementedBy(C2)], IProvideBase, '')
'Child->Base'
Of course, this means that ``None`` can't be registered. This is an
exception to the statement, made earlier, that the registry doesn't
@ -383,25 +383,25 @@ You can adapt multiple specifications:
.. doctest::
>>> registry.register([IRequire1, IQ], IProvide2, '', '1q2')
>>> registry.lookup([IRequire1, IQ], IProvide2, '')
>>> registry.register([IRequireBase, IQ], IProvideChild, '', '1q2')
>>> registry.lookup([IRequireBase, IQ], IProvideChild, '')
'1q2'
>>> registry.lookup([IRequire2, IQ], IProvide1, '')
>>> registry.lookup([IRequireChild, IQ], IProvideBase, '')
'1q2'
>>> class IS(zope.interface.Interface):
... pass
>>> registry.lookup([IRequire2, IS], IProvide1, '')
>>> registry.lookup([IRequireChild, IS], IProvideBase, '')
>>> class IQ2(IQ):
... pass
>>> registry.lookup([IRequire2, IQ2], IProvide1, '')
>>> registry.lookup([IRequireChild, IQ2], IProvideBase, '')
'1q2'
>>> registry.register([IRequire1, IQ2], IProvide2, '', '1q22')
>>> registry.lookup([IRequire2, IQ2], IProvide1, '')
'1q22'
>>> registry.register([IRequireBase, IQ2], IProvideChild, '', '(Base,Q2)->Child')
>>> registry.lookup([IRequireChild, IQ2], IProvideBase, '')
'(Base,Q2)->Child'
Multi-adaptation
----------------
@ -458,9 +458,9 @@ As with single adapters, you can define default adapters by specifying
.. doctest::
>>> registry.register([None, IQ], IProvide2, '', 'q2')
>>> registry.lookup([IS, IQ], IProvide2, '')
'q2'
>>> registry.register([None, IQ], IProvideChild, '', '(None,Q)->Child')
>>> registry.lookup([IS, IQ], IProvideChild, '')
'(None,Q)->Child'
Null Adapters
=============
@ -469,11 +469,11 @@ You can also adapt **no** specification:
.. doctest::
>>> registry.register([], IProvide2, '', 2)
>>> registry.lookup([], IProvide2, '')
2
>>> registry.lookup([], IProvide1, '')
2
>>> registry.register([], IProvideChild, '', '[]->Child')
>>> registry.lookup([], IProvideChild, '')
'[]->Child'
>>> registry.lookup([], IProvideBase, '')
'[]->Child'
Listing named adapters
----------------------
@ -483,27 +483,27 @@ adapters for given interfaces:
.. doctest::
>>> adapters = list(registry.lookupAll([IRequire1], IProvide1))
>>> adapters = list(registry.lookupAll([IRequireBase], IProvideBase))
>>> adapters.sort()
>>> assert adapters == [(u'', 11), (u'bob', "Bob's 12")]
>>> assert adapters == [(u'', 'Base->Base'), (u'bob', "Bob's 12")]
This works for multi-adapters too:
.. doctest::
>>> registry.register([IRequire1, IQ2], IProvide2, 'bob', '1q2 for bob')
>>> adapters = list(registry.lookupAll([IRequire2, IQ2], IProvide1))
>>> registry.register([IRequireBase, IQ2], IProvideChild, 'bob', '(Base,Q2)->Child for bob')
>>> adapters = list(registry.lookupAll([IRequireChild, IQ2], IProvideBase))
>>> adapters.sort()
>>> assert adapters == [(u'', '1q22'), (u'bob', '1q2 for bob')]
>>> assert adapters == [(u'', '(Base,Q2)->Child'), (u'bob', '(Base,Q2)->Child for bob')]
And even null adapters:
.. doctest::
>>> registry.register([], IProvide2, 'bob', 3)
>>> adapters = list(registry.lookupAll([], IProvide1))
>>> registry.register([], IProvideChild, 'bob', 3)
>>> adapters = list(registry.lookupAll([], IProvideBase))
>>> adapters.sort()
>>> assert adapters == [(u'', 2), (u'bob', 3)]
>>> assert adapters == [(u'', '[]->Child'), (u'bob', 3)]
Subscriptions
=============
@ -516,9 +516,9 @@ the subscribed objects:
.. doctest::
>>> registry.subscribe([IRequire1], IProvide2, 'sub12 1')
>>> registry.subscriptions([IRequire1], IProvide2)
['sub12 1']
>>> registry.subscribe([IRequireBase], IProvideChild, 'Base->Child (1)')
>>> registry.subscriptions([IRequireBase], IProvideChild)
['Base->Child (1)']
Note that, unlike regular adapters, subscriptions are unnamed.
@ -526,9 +526,9 @@ You can have multiple subscribers for the same specification:
.. doctest::
>>> registry.subscribe([IRequire1], IProvide2, 'sub12 2')
>>> registry.subscriptions([IRequire1], IProvide2)
['sub12 1', 'sub12 2']
>>> registry.subscribe([IRequireBase], IProvideChild, 'Base->Child (2)')
>>> registry.subscriptions([IRequireBase], IProvideChild)
['Base->Child (1)', 'Base->Child (2)']
If subscribers are registered for the same required interfaces, they
are returned in the order of definition.
@ -537,62 +537,72 @@ You can register subscribers for all specifications using ``None``:
.. doctest::
>>> registry.subscribe([None], IProvide1, 'sub_1')
>>> registry.subscriptions([IRequire2], IProvide1)
['sub_1', 'sub12 1', 'sub12 2']
>>> registry.subscribe([None], IProvideBase, 'None->Base')
>>> registry.subscriptions([IRequireChild], IProvideBase)
['None->Base', 'Base->Child (1)', 'Base->Child (2)']
Note that the new subscriber is returned first. Subscribers defined
for less general required interfaces are returned before subscribers
for more general interfaces.
Note that the new subscriber is returned first.
Subscribers defined for less specific required interfaces are returned
before subscribers for more specific interfaces:
.. doctest::
>>> class IRequireGrandchild(IRequireChild):
... pass
>>> registry.subscribe([IRequireChild], IProvideBase, 'Child->Base')
>>> registry.subscribe([IRequireGrandchild], IProvideBase, 'Grandchild->Base')
>>> registry.subscriptions([IRequireGrandchild], IProvideBase)
['None->Base', 'Base->Child (1)', 'Base->Child (2)', 'Child->Base', 'Grandchild->Base']
Subscriptions may be combined over multiple compatible specifications:
.. doctest::
>>> registry.subscriptions([IRequire2], IProvide1)
['sub_1', 'sub12 1', 'sub12 2']
>>> registry.subscribe([IRequire1], IProvide1, 'sub11')
>>> registry.subscriptions([IRequire2], IProvide1)
['sub_1', 'sub12 1', 'sub12 2', 'sub11']
>>> registry.subscribe([IRequire2], IProvide2, 'sub22')
>>> registry.subscriptions([IRequire2], IProvide1)
['sub_1', 'sub12 1', 'sub12 2', 'sub11', 'sub22']
>>> registry.subscriptions([IRequire2], IProvide2)
['sub12 1', 'sub12 2', 'sub22']
>>> registry.subscriptions([IRequireChild], IProvideBase)
['None->Base', 'Base->Child (1)', 'Base->Child (2)', 'Child->Base']
>>> registry.subscribe([IRequireBase], IProvideBase, 'Base->Base')
>>> registry.subscriptions([IRequireChild], IProvideBase)
['None->Base', 'Base->Child (1)', 'Base->Child (2)', 'Base->Base', 'Child->Base']
>>> registry.subscribe([IRequireChild], IProvideChild, 'Child->Child')
>>> registry.subscriptions([IRequireChild], IProvideBase)
['None->Base', 'Base->Child (1)', 'Base->Child (2)', 'Base->Base', 'Child->Child', 'Child->Base']
>>> registry.subscriptions([IRequireChild], IProvideChild)
['Base->Child (1)', 'Base->Child (2)', 'Child->Child']
Subscriptions can be on multiple specifications:
.. doctest::
>>> registry.subscribe([IRequire1, IQ], IProvide2, 'sub1q2')
>>> registry.subscriptions([IRequire1, IQ], IProvide2)
['sub1q2']
>>> registry.subscribe([IRequireBase, IQ], IProvideChild, '(Base,Q)->Child')
>>> registry.subscriptions([IRequireBase, IQ], IProvideChild)
['(Base,Q)->Child']
As with single subscriptions and non-subscription adapters, you can
specify ``None`` for the first required interface, to specify a default:
.. doctest::
>>> registry.subscribe([None, IQ], IProvide2, 'sub_q2')
>>> registry.subscriptions([IS, IQ], IProvide2)
['sub_q2']
>>> registry.subscriptions([IRequire1, IQ], IProvide2)
['sub_q2', 'sub1q2']
>>> registry.subscribe([None, IQ], IProvideChild, '(None,Q)->Child')
>>> registry.subscriptions([IS, IQ], IProvideChild)
['(None,Q)->Child']
>>> registry.subscriptions([IRequireBase, IQ], IProvideChild)
['(None,Q)->Child', '(Base,Q)->Child']
You can have subscriptions that are independent of any specifications:
.. doctest::
>>> list(registry.subscriptions([], IProvide1))
>>> list(registry.subscriptions([], IProvideBase))
[]
>>> registry.subscribe([], IProvide2, 'sub2')
>>> registry.subscriptions([], IProvide1)
>>> registry.subscribe([], IProvideChild, 'sub2')
>>> registry.subscriptions([], IProvideBase)
['sub2']
>>> registry.subscribe([], IProvide1, 'sub1')
>>> registry.subscriptions([], IProvide1)
>>> registry.subscribe([], IProvideBase, 'sub1')
>>> registry.subscriptions([], IProvideBase)
['sub2', 'sub1']
>>> registry.subscriptions([], IProvide2)
>>> registry.subscriptions([], IProvideChild)
['sub2']
Unregistering subscribers
@ -603,18 +613,18 @@ can unregister a *specific* subscriber:
.. doctest::
>>> registry.unsubscribe([IRequire1], IProvide1, 'sub11')
>>> registry.subscriptions([IRequire1], IProvide1)
['sub_1', 'sub12 1', 'sub12 2']
>>> registry.unsubscribe([IRequireBase], IProvideBase, 'Base->Base')
>>> registry.subscriptions([IRequireBase], IProvideBase)
['None->Base', 'Base->Child (1)', 'Base->Child (2)']
If we don't specify a value, then *all* subscribers matching the given
interfaces will be unsubscribed:
.. doctest::
>>> registry.unsubscribe([IRequire1], IProvide2)
>>> registry.subscriptions([IRequire1], IProvide1)
['sub_1']
>>> registry.unsubscribe([IRequireBase], IProvideChild)
>>> registry.subscriptions([IRequireBase], IProvideBase)
['None->Base']
Subscription adapters
@ -665,8 +675,8 @@ To register a handler, simply provide ``None`` as the provided interface:
>>> def handler(event):
... print('handler', event)
>>> registry.subscribe([IRequire1], None, handler)
>>> registry.subscriptions([IRequire1], None) == [handler]
>>> registry.subscribe([IRequireBase], None, handler)
>>> registry.subscriptions([IRequireBase], None) == [handler]
True

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@ -338,7 +338,7 @@ class IInterface(ISpecification, IElement):
def names(all=False):
"""Get the interface attribute names
Return a sequence of the names of the attributes, including
Return a collection of the names of the attributes, including
methods, included in the interface definition.
Normally, only directly defined attributes are included. If
@ -349,7 +349,7 @@ class IInterface(ISpecification, IElement):
def namesAndDescriptions(all=False):
"""Get the interface attribute names and descriptions
Return a sequence of the names and descriptions of the
Return a collection of the names and descriptions of the
attributes, including methods, as name-value pairs, included
in the interface definition.