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##############################################################################
#
# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Zope 3 Component Architecture
"""
import sys
from zope.hookable import hookable
from zope.interface import Interface
from zope.interface.interfaces import ComponentLookupError
from zope.interface.interfaces import IComponentLookup
from zope.component.interfaces import IFactory
# getSiteManager() returns a component registry. Although the term
# "site manager" is deprecated in favor of "component registry",
# the old term is kept around to maintain a stable API.
base = None
@hookable
def getSiteManager(context=None):
""" See IComponentArchitecture.
"""
global base
if context is None:
if base is None:
from zope.component.globalregistry import base
return base
else:
# Use the global site manager to adapt context to `IComponentLookup`
# to avoid the recursion implied by using a local `getAdapter()` call.
try:
return IComponentLookup(context)
except TypeError as error:
raise ComponentLookupError(*error.args)
# Adapter API
def getAdapterInContext(object, interface, context):
adapter = queryAdapterInContext(object, interface, context)
if adapter is None:
raise ComponentLookupError(object, interface)
return adapter
def queryAdapterInContext(object, interface, context, default=None):
conform = getattr(object, '__conform__', None)
if conform is not None:
try:
adapter = conform(interface)
except TypeError:
# We got a TypeError. It might be an error raised by
# the __conform__ implementation, or *we* may have
# made the TypeError by calling an unbound method
# (object is a class). In the later case, we behave
# as though there is no __conform__ method. We can
# detect this case by checking whether there is more
# than one traceback object in the traceback chain:
if sys.exc_info()[2].tb_next is not None:
# There is more than one entry in the chain, so
# reraise the error:
raise
# This clever trick is from Phillip Eby
else:
if adapter is not None:
return adapter
if interface.providedBy(object):
return object
return getSiteManager(context).queryAdapter(object, interface, '', default)
def getAdapter(object, interface=Interface, name=u'', context=None):
adapter = queryAdapter(object, interface, name, None, context)
if adapter is None:
raise ComponentLookupError(object, interface, name)
return adapter
def queryAdapter(object, interface=Interface, name=u'', default=None,
context=None):
if context is None:
return adapter_hook(interface, object, name, default)
return getSiteManager(context).queryAdapter(object, interface, name,
default)
def getMultiAdapter(objects, interface=Interface, name=u'', context=None):
adapter = queryMultiAdapter(objects, interface, name, context=context)
if adapter is None:
raise ComponentLookupError(objects, interface, name)
return adapter
def queryMultiAdapter(objects, interface=Interface, name=u'', default=None,
context=None):
try:
sitemanager = getSiteManager(context)
except ComponentLookupError:
# Oh blast, no site manager. This should *never* happen!
return default
return sitemanager.queryMultiAdapter(objects, interface, name, default)
def getAdapters(objects, provided, context=None):
try:
sitemanager = getSiteManager(context)
except ComponentLookupError:
# Oh blast, no site manager. This should *never* happen!
return []
return sitemanager.getAdapters(objects, provided)
def subscribers(objects, interface, context=None):
try:
sitemanager = getSiteManager(context)
except ComponentLookupError:
# Oh blast, no site manager. This should *never* happen!
return []
return sitemanager.subscribers(objects, interface)
def handle(*objects):
getSiteManager(None).subscribers(objects, None)
#############################################################################
# Register the component architectures adapter hook, with the adapter hook
# registry of the `zope.inteface` package. This way we will be able to call
# interfaces to create adapters for objects. For example, `I1(ob)` is
# equvalent to `getAdapterInContext(I1, ob, '')`.
@hookable
def adapter_hook(interface, object, name='', default=None):
try:
sitemanager = getSiteManager()
except ComponentLookupError: #pragma NO COVER w/o context, cannot test
# Oh blast, no site manager. This should *never* happen!
return None
return sitemanager.queryAdapter(object, interface, name, default)
import zope.interface.interface
zope.interface.interface.adapter_hooks.append(adapter_hook)
#############################################################################
# Utility API
def getUtility(interface, name='', context=None):
utility = queryUtility(interface, name, context=context)
if utility is not None:
return utility
raise ComponentLookupError(interface, name)
def queryUtility(interface, name='', default=None, context=None):
return getSiteManager(context).queryUtility(interface, name, default)
def getUtilitiesFor(interface, context=None):
return getSiteManager(context).getUtilitiesFor(interface)
def getAllUtilitiesRegisteredFor(interface, context=None):
return getSiteManager(context).getAllUtilitiesRegisteredFor(interface)
_marker = object()
def queryNextUtility(context, interface, name='', default=None):
"""Query for the next available utility.
Find the next available utility providing `interface` and having the
specified name. If no utility was found, return the specified `default`
value.
"""
try:
sm = getSiteManager(context)
except ComponentLookupError:
return default
bases = sm.__bases__
for base in bases:
util = base.queryUtility(interface, name, _marker)
if util is not _marker:
return util
return default
def getNextUtility(context, interface, name=''):
"""Get the next available utility.
If no utility was found, a `ComponentLookupError` is raised.
"""
util = queryNextUtility(context, interface, name, _marker)
if util is _marker:
raise ComponentLookupError(
"No more utilities for %s, '%s' have been found." % (
interface, name))
return util
# Factories
def createObject(__factory_name, *args, **kwargs):
"""Invoke the named factory and return the result.
``__factory_name`` is a positional-only argument.
"""
context = kwargs.pop('context', None)
return getUtility(IFactory, __factory_name, context)(*args, **kwargs)
def getFactoryInterfaces(name, context=None):
"""Return the interface provided by the named factory's objects
Result might be a single interface. XXX
"""
return getUtility(IFactory, name, context).getInterfaces()
def getFactoriesFor(interface, context=None):
"""Return info on all factories implementing the given interface.
"""
utils = getSiteManager(context)
for (name, factory) in utils.getUtilitiesFor(IFactory):
interfaces = factory.getInterfaces()
try:
if interfaces.isOrExtends(interface):
yield name, factory
except AttributeError:
for iface in interfaces:
if iface.isOrExtends(interface):
yield name, factory
break