path: root/src/zope/component/interfaces.py

############################################################################
#
# 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.
#
############################################################################
"""
Component and Component Architecture Interfaces

The `IComponentArchitecture` and `IComponentRegistrationConvenience` interfaces
are provided by `zope.component` directly.
"""
from zope.interface import Attribute
from zope.interface import Interface


# BBB 2011-09-09, import interfaces from zope.interface
import zope.deferredimport
zope.deferredimport.deprecatedFrom(
    "Import from zope.interface.interfaces",
    "zope.interface.interfaces",
    'ComponentLookupError',
    'Invalid',
    'IObjectEvent',
    'ObjectEvent',
    'IComponentLookup',
    'IRegistration',
    'IUtilityRegistration',
    '_IBaseAdapterRegistration',
    'IAdapterRegistration',
    'ISubscriptionAdapterRegistration',
    'IHandlerRegistration',
    'IRegistrationEvent',
    'RegistrationEvent',
    'IRegistered',
    'Registered',
    'IUnregistered',
    'Unregistered',
    'IComponentRegistry',
    'IComponents',
)


class IComponentArchitecture(Interface):
    """The Component Architecture is defined by two key components: Adapters
    and Utiltities. Both are managed by site managers. All other components
    build on top of them.
    """
    # Site Manager API

    def getGlobalSiteManager():
        """Return the global site manager.

        This function should never fail and always return an object that
        provides `zope.interface.interfaces.IComponents`.
        """

    def getSiteManager(context=None):
        """Get the nearest site manager in the given context.

        If *context* is `None`, return the global site manager.

        If the *context* is not `None`, it is expected that an adapter
        from the *context* to
        :mod:`zope.interface.interfaces.IComponentLookup` can be
        found. If no adapter is found, a
        `~zope.interface.interfaces.ComponentLookupError` is raised.
        """

    # Utility API

    def getUtility(interface, name='', context=None):
        """Get the utility that provides interface

        Returns the nearest utility to the context that implements the
        specified interface. If one is not found, raises
        `~zope.interface.interfaces.ComponentLookupError`.
        """

    def queryUtility(interface, name='', default=None, context=None):
        """Look for the utility that provides *interface*

        Returns the nearest utility to the *context* that implements the
        specified interface. If one is not found, returns *default*.
        """

    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.
        """

    def getNextUtility(context, interface, name=''):
        """Get the next available utility.

        If no utility was found, a `~zope.interface.interfaces.ComponentLookupError` is raised.
        """

    def getUtilitiesFor(interface, context=None):
        """Return the utilities that provide an interface

        An iterable of utility name-value pairs is returned.
        """

    def getAllUtilitiesRegisteredFor(interface, context=None):
        """Return all registered utilities for an interface

        This includes overridden utilities.

        An iterable of utility instances is returned.  No names are
        returned.
        """

    # Adapter API

    def getAdapter(object,
                   interface=Interface, name=u'',
                   context=None):
        """Get a named adapter to an interface for an object

        Returns an adapter that can adapt object to interface.  If a matching
        adapter cannot be found, raises `~zope.interface.interfaces.ComponentLookupError`.
        """

    def getAdapterInContext(object, interface, context):
        """Get a special adapter to an interface for an object

        .. note::
            This method should only be used if a custom context
            needs to be provided to provide custom component
            lookup. Otherwise, call the interface, as in::

               interface(object)

        Returns an adapter that can adapt object to interface. If a
        matching adapter cannot be found, raises
        `~zope.interface.interfaces.ComponentLookupError`.

        If the object has a ``__conform__`` method, this method will be
        called with the requested interface. If the method returns a
        non-None value, that value will be returned. Otherwise, if the
        object already implements the interface, the object will be
        returned.
        """

    def getMultiAdapter(objects,
                        interface=Interface, name='',
                        context=None):
        """Look for a multi-adapter to an *interface* for an *objects*

        Returns a multi-adapter that can adapt *objects* to *interface*.
        If a matching adapter cannot be found, raises
        `~zope.interface.interfaces.ComponentLookupError`.

        The name consisting of an empty string is reserved for unnamed
        adapters. The unnamed adapter methods will often call the
        named adapter methods with an empty string for a name.
        """

    def queryAdapter(object, interface=Interface, name=u'',
                     default=None, context=None):
        """Look for a named adapter to an interface for an object

        Returns an adapter that can adapt object to interface. If a
        matching adapter cannot be found, returns the default.
        """

    def queryAdapterInContext(object, interface, context, default=None):
        """
        Look for a special adapter to an interface for an object

        .. note::

            This method should only be used if a custom context
            needs to be provided to provide custom component lookup.
            Otherwise, call the interface, as in::

                interface(object, default)

        Returns an adapter that can adapt object to interface. If a
        matching adapter cannot be found, returns the default.

        If the object has a ``__conform__`` method, this method will be
        called with the requested interface. If the method returns a
        non-None value, that value will be returned. Otherwise, if the
        object already implements the interface, the object will be
        returned.
        """

    def queryMultiAdapter(objects,
                          interface=Interface, name=u'',
                          default=None,
                          context=None):
        """Look for a multi-adapter to an interface for objects

        Returns a multi-adapter that can adapt objects to interface.  If a
        matching adapter cannot be found, returns the default.

        The name consisting of an empty string is reserved for unnamed
        adapters. The unnamed adapter methods will often call the
        named adapter methods with an empty string for a name.
        """

    def getAdapters(objects, provided, context=None):
        """
        Look for all matching adapters to a provided interface for
        objects

        Return a list of adapters that match. If an adapter is named,
        only the most specific adapter of a given name is returned.
        """

    def subscribers(required, provided, context=None):
        """Get subscribers

        Subscribers are returned that provide the provided interface
        and that depend on and are computed from the sequence of
        required objects.
        """

    def handle(*objects):
        """Call all of the handlers for the given objects

        Handlers are subscription adapter factories that don't produce
        anything. They do all of their work when called. Handlers are
        typically used to handle events.
        """

    def adapts(*interfaces):
        """
        Declare that a class adapts the given interfaces.

        This function can only be used in a class definition.

        (TODO, allow classes to be passed as well as interfaces.)
        """

    # Factory service

    def createObject(factory_name, *args, **kwargs):
        """Create an object using a factory

        Finds the named factory in the current site and calls it with
        the given arguments. If a matching factory cannot be found
        raises `~zope.interface.interfaces.ComponentLookupError`.
        Returns the created object.

        A context keyword argument can be provided to cause the
        factory to be looked up in a location other than the current
        site. (Of course, this means that it is impossible to pass a
        keyword argument named "context" to the factory.
        """

    def getFactoryInterfaces(name, context=None):
        """Get interfaces implemented by a factory

        Finds the factory of the given name that is nearest to the
        context, and returns the interface or interface tuple that
        object instances created by the named factory will implement.
        """

    def getFactoriesFor(interface, context=None):
        """Return a tuple (name, factory) of registered factories that
        create objects which implement the given interface.
        """


class IRegistry(Interface):
    """Object that supports component registry
    """

    def registrations():
        """Return an iterable of component registrations
        """

class IComponentRegistrationConvenience(Interface):
    """API for registering components.

    .. caution::
        This API should only be used from test or
        application-setup code. This api shouldn't be used by regular
        library modules, as component registration is a configuration
        activity.
    """

    def provideUtility(component, provides=None, name=u''):
        """Register a utility globally

        A utility is registered to provide an interface with a
        name. If a component provides only one interface, then the
        provides argument can be omitted and the provided interface
        will be used. (In this case, provides argument can still be
        provided to provide a less specific interface.)
        """

    def provideAdapter(factory, adapts=None, provides=None, name=u''):
        """Register an adapter globally

        An adapter is registered to provide an interface with a name
        for some number of object types. If a factory implements only
        one interface, then the provides argument can be omitted and
        the provided interface will be used. (In this case, a provides
        argument can still be provided to provide a less specific
        interface.)

        If the factory has an adapts declaration, then the adapts
        argument can be omitted and the declaration will be used.  (An
        adapts argument can be provided to override the declaration.)
        """

    def provideSubscriptionAdapter(factory, adapts=None, provides=None):
        """Register a subscription adapter

        A subscription adapter is registered to provide an interface
        for some number of object types. If a factory implements only
        one interface, then the provides argument can be omitted and
        the provided interface will be used. (In this case, a provides
        argument can still be provided to provide a less specific
        interface.)

        If the factory has an adapts declaration, then the adapts
        argument can be omitted and the declaration will be used.  (An
        adapts argument can be provided to override the declaration.)
        """

    def provideHandler(handler, adapts=None):
        """Register a handler

        Handlers are subscription adapter factories that don't produce
        anything.  They do all of their work when called.  Handlers
        are typically used to handle events.

        If the handler has an adapts declaration, then the adapts
        argument can be omitted and the declaration will be used.  (An
        adapts argument can be provided to override the declaration.)
        """


class IPossibleSite(Interface):
    """An object that could be a site.
    """

    def setSiteManager(sitemanager):
        """Sets the site manager for this object.
        """

    def getSiteManager():
        """Returns the site manager contained in this object.

        If there isn't a site manager, raise a component lookup.
        """

class ISite(IPossibleSite):
    """Marker interface to indicate that we have a site"""

class Misused(Exception):
    """A component is being used (registered) for the wrong interface."""


class IFactory(Interface):
    """A factory is responsible for creating other components."""

    title = Attribute("The factory title.")

    description = Attribute("A brief description of the factory.")

    def __call__(*args, **kw):
        """Return an instance of the objects we're a factory for."""


    def getInterfaces():
        """Get the interfaces implemented by the factory

        Return the interface(s), as an instance of Implements, that objects
        created by this factory will implement. If the callable's Implements
        instance cannot be created, an empty Implements instance is returned.
        """


# Internal helpers

def _inherits_docs(func, iface):
    doc = iface[func.__name__].__doc__
    # By adding the ..seealso:: we get a link from our overview page
    # to the specific narrative place where the function is described, because
    # our overview page uses :noindex:
    doc += "\n        .. seealso::"
    doc += "\n           Function `~zope.component.%s` for notes, and " % (func.__name__,)
    doc += "\n           `~zope.component.interfaces.%s` for the defining interface." % (iface.__name__,)
    doc += "\n"
    func.__doc__ = doc
    return func

def inherits_arch_docs(func):
    return _inherits_docs(func, IComponentArchitecture)

def inherits_reg_docs(func):
    return _inherits_docs(func, IComponentRegistrationConvenience)