Source code for grokcore.viewlet.directive

##############################################################################
#
# Copyright (c) 2006-2007 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.
#
##############################################################################
"""Grok directives.
"""

import martian
from martian.error import GrokError
from martian.util import scan_for_classes

from grokcore.viewlet.interfaces import IViewletManager



[docs]
class viewletmanager(martian.Directive):
    scope = martian.CLASS_OR_MODULE
    store = martian.ONCE
    validate = martian.validateInterfaceOrClass

    @classmethod
    def get_default(cls, component, module=None, **data):
        components = list(scan_for_classes(module, IViewletManager))
        if len(components) == 0:
            raise GrokError(
                "No module-level viewletmanager for %r, please use the "
                "'viewletmanager' directive." % (component), component)
        elif len(components) == 1:
            component = components[0]
        else:
            raise GrokError(
                "Multiple possible viewletmanagers for %r, please use the "
                "'viewletmanager' directive."
                % (component), component)
        return component