1# Copyright 2013 Red Hat, Inc.
2#
3#    Licensed under the Apache License, Version 2.0 (the "License"); you may
4#    not use this file except in compliance with the License. You may obtain
5#    a copy of the License at
6#
7#         http://www.apache.org/licenses/LICENSE-2.0
8#
9#    Unless required by applicable law or agreed to in writing, software
10#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12#    License for the specific language governing permissions and limitations
13#    under the License.
14
15import copy
16
17from oslo_reports.models import base as base_model
18from oslo_reports.views.json import generic as jsonviews
19from oslo_reports.views.text import generic as textviews
20from oslo_reports.views.xml import generic as xmlviews
21
22
23class ModelWithDefaultViews(base_model.ReportModel):
24    """A Model With Default Views of Various Types
25
26    A model with default views has several predefined views,
27    each associated with a given type.  This is often used for
28    when a submodel should have an attached view, but the view
29    differs depending on the serialization format
30
31    Parameters are as the superclass, except for any
32    parameters ending in '_view': these parameters
33    get stored as default views.
34
35    The default 'default views' are
36
37    text
38        :class:`oslo_reports.views.text.generic.KeyValueView`
39    xml
40        :class:`oslo_reports.views.xml.generic.KeyValueView`
41    json
42        :class:`oslo_reports.views.json.generic.KeyValueView`
43
44    .. function:: to_type()
45
46       ('type' is one of the 'default views' defined for this model)
47       Serializes this model using the default view for 'type'
48
49       :rtype: str
50       :returns: this model serialized as 'type'
51    """
52
53    def __init__(self, *args, **kwargs):
54        self.views = {
55            'text': textviews.KeyValueView(),
56            'json': jsonviews.KeyValueView(),
57            'xml': xmlviews.KeyValueView()
58        }
59
60        newargs = copy.copy(kwargs)
61        for k in kwargs:
62            if k.endswith('_view'):
63                self.views[k[:-5]] = kwargs[k]
64                del newargs[k]
65        super(ModelWithDefaultViews, self).__init__(*args, **newargs)
66
67    def set_current_view_type(self, tp, visited=None):
68        self.attached_view = self.views[tp]
69        super(ModelWithDefaultViews, self).set_current_view_type(tp, visited)
70
71    def __getattr__(self, attrname):
72        if attrname[:3] == 'to_':
73            if self.views[attrname[3:]] is not None:
74                return lambda: self.views[attrname[3:]](self)
75            else:
76                raise NotImplementedError((
77                    "Model {cn.__module__}.{cn.__name__} does not have" +
78                    " a default view for "
79                    "{tp}").format(cn=type(self), tp=attrname[3:]))
80        else:
81            return super(ModelWithDefaultViews, self).__getattr__(attrname)
82