2 # NEPI, a framework to manage network experiments
3 # Copyright (C) 2013 INRIA
5 # This program is free software: you can redistribute it and/or modify
6 # it under the terms of the GNU General Public License as published by
7 # the Free Software Foundation, either version 3 of the License, or
8 # (at your option) any later version.
10 # This program is distributed in the hope that it will be useful,
11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 # GNU General Public License for more details.
15 # You should have received a copy of the GNU General Public License
16 # along with this program. If not, see <http://www.gnu.org/licenses/>.
18 # Author: Alina Quereilhac <alina.quereilhac@inria.fr>
30 """ Differents flags to characterize an attribute
33 # Attribute value can not be read (it is hidden to the user)
36 # Attribute value can not be modified (it is not editable by the user)
39 # Attribute value can be modified only before deployment
42 # Attribute value will be used only during the deployment face
43 Construct = 1 << 3 | Design # 8 + 4
45 # Attribute provides credentials to access resources
46 Credential = 1 << 4 | Design # 16 + 4
48 # Attribute is a filter used to discover resources
49 Filter = 1 << 5 | Design # 32 + 4
52 class Attribute(object):
54 .. class:: Class Args :
56 An Attribute reflects a configuration parameter for
57 a particular resource. Attributes might be read only or
60 :param name: Name of the attribute
63 :param help: Attribute description
66 :param type: The type expected for the attribute value.
67 Should be one of Attribute.Types .
70 :param flags: Defines attribute behavior (i.e. whether it is read-only,
71 read and write, etc). This parameter should take its values from
72 Attribute.Flags. Flags values can be bitwised.
75 :param default: Default value of the attribute
76 :type default: depends on the type of attribute
78 :param allowed: List of values that the attribute can take.
79 This parameter is only meaningful for Enumerate type attributes.
82 :param range: (max, min) tuple with range of possible values for
84 This parameter is only meaningful for Integer or Double type
86 :type range: (int, int) or (float, float)
88 :param set_hook: Function that will be executed when ever a new
89 value is set for the attribute.
90 :type set_hook: function
93 def __init__(self, name, help, type = Types.String,
94 flags = None, default = None, allowed = None,
95 range = None, set_hook = None):
99 self._flags = flags or 0
100 self._allowed = allowed
102 self._default = self._value = default
103 # callback to be invoked upon changing the
105 self.set_hook = set_hook
109 """ Returns the name of the attribute """
114 """ Returns the default value of the attribute """
119 """ Returns the type of the attribute """
124 """ Returns the help of the attribute """
129 """ Returns the flags of the attribute """
134 """ Returns the allowed value for this attribute """
139 """ Returns the range of the attribute """
142 def has_flag(self, flag):
143 """ Returns true if the attribute has the flag 'flag'
145 :param flag: Flag that need to be ckecked
148 return (self._flags & flag) == flag
151 """ Returns the value of the attribute """
154 def set_value(self, value):
155 """ Change the value of the attribute after checking the type """
158 if self.type == Types.Enumerate:
159 valid = value in self._allowed
161 if self.type in [Types.Double, Types.Integer] and self.range:
162 (min, max) = self.range
166 valid = (value >= min and value <= max)
168 valid = valid and self.is_valid_value(value)
172 # Hook receives old value, new value
173 value = self.set_hook(self._value, value)
177 raise ValueError("Invalid value %s for attribute %s" %
178 (str(value), self.name))
180 value = property(get_value, set_value)
182 def is_valid_value(self, value):
183 """ Attribute subclasses will override this method to add
184 adequate validation"""
187 def has_changed(self):
188 """ Returns true if the value has changed from the default """
189 return self.value != self.default