1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
|
##############################################################################
#
# Copyright (c) 2004 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.
#
##############################################################################
"""Overriding attr methods
Examples for overriding attribute access methods.
"""
from persistent import Persistent
def _resettingJar():
from persistent.tests.utils import ResettingJar
return ResettingJar()
def _rememberingJar():
from persistent.tests.utils import RememberingJar
return RememberingJar()
class OverridesGetattr(Persistent):
"""Example of overriding __getattr__
"""
def __getattr__(self, name):
"""Get attributes that can't be gotten the usual way
"""
# Don't pretend we have any special attributes.
if name.startswith("__") and name.endswrith("__"):
raise AttributeError(name)
else:
return name.upper(), self._p_changed
class VeryPrivate(Persistent):
"""Example of overriding __getattribute__, __setattr__, and __delattr__
"""
def __init__(self, **kw):
self.__dict__['__secret__'] = kw.copy()
def __getattribute__(self, name):
"""Get an attribute value
See the very important note in the comment below!
"""
#################################################################
# IMPORTANT! READ THIS! 8->
#
# We *always* give Persistent a chance first.
# Persistent handles certain special attributes, like _p_
# attributes. In particular, the base class handles __dict__
# and __class__.
#
# We call _p_getattr. If it returns True, then we have to
# use Persistent.__getattribute__ to get the value.
#
#################################################################
if Persistent._p_getattr(self, name):
return Persistent.__getattribute__(self, name)
# Data should be in our secret dictionary:
secret = self.__dict__['__secret__']
if name in secret:
return secret[name]
# Maybe it's a method:
meth = getattr(self.__class__, name, None)
if meth is None:
raise AttributeError(name)
return meth.__get__(self, self.__class__)
def __setattr__(self, name, value):
"""Set an attribute value
"""
#################################################################
# IMPORTANT! READ THIS! 8->
#
# We *always* give Persistent a chance first.
# Persistent handles certain special attributes, like _p_
# attributes.
#
# We call _p_setattr. If it returns True, then we are done.
# It has already set the attribute.
#
#################################################################
if Persistent._p_setattr(self, name, value):
return
self.__dict__['__secret__'][name] = value
if not name.startswith('tmp_'):
self._p_changed = 1
def __delattr__(self, name):
"""Delete an attribute value
"""
#################################################################
# IMPORTANT! READ THIS! 8->
#
# We *always* give Persistent a chance first.
# Persistent handles certain special attributes, like _p_
# attributes.
#
# We call _p_delattr. If it returns True, then we are done.
# It has already deleted the attribute.
#
#################################################################
if Persistent._p_delattr(self, name):
return
del self.__dict__['__secret__'][name]
if not name.startswith('tmp_'):
self._p_changed = 1
|
