Source Code for Module brisa.utils.properties

 1  # Licensed under the MIT license 
 2  # http://opensource.org/licenses/mit-license.php or see LICENSE file. 
 3  # Copyright 2007-2008 Brisa Team <brisa-develop@garage.maemo.org> 
 4   
 5  """ Facilities for python properties generation. 
 6  """ 
 7   
 8   
 9 -def gen_property_with_default(name, fget=None, fset=None, doc=""): 
10      """ Generates a property of a name either with a default fget or a default 
11      fset. 
12   
13      @param name: property name 
14      @param fget: default fget 
15      @param fset: default fset 
16      @param doc: documentation for the property 
17   
18      @type name: string 
19      @type fget: callable or None 
20      @type fset: callable or None 
21      @type doc: string 
22      """ 
23      if fget == None and fset == None: 
24          raise NotImplementedError("fget or fset must be not null") 
25   
26      internal_name = '%s%s' % ("_prop_", name) 
27   
28      def getter(self): 
29          if not internal_name in dir(self): 
30              setattr(self, internal_name, "") 
31          return getattr(self, internal_name) 
32   
33      def setter(self, value): 
34          return setattr(self, internal_name, value) 
35   
36      if fget is None: 
37          return property(getter, fset, doc=doc) 
38   
39      return property(fget, setter, doc=doc) 
40   
41   
42 -def gen_property_of_type(name, _type, doc=""): 
43      """ Generates a type-forced property associated with a name. Provides type 
44      checking on the setter (coherence between value to be set and the type 
45      specified). 
46   
47      @param name: property name 
48      @param _type: force type 
49      @param doc: documentation for the property 
50   
51      @type name: string 
52      @type _type: type 
53      @type doc: string 
54      """ 
55      internal_name = '%s%s' % ("_prop_", name) 
56   
57      def getter(self): 
58          return getattr(self, internal_name) 
59   
60      def setter(self, value): 
61          if isinstance(value, _type): 
62              return setattr(self, internal_name, value) 
63          else: 
64              raise TypeError(("invalid type '%s' for property %s:" 
65                               "%s is required.") % 
66                              (type(value).__name__, name, type(_type).__name__)) 
67   
68      return property(getter, setter, doc=doc) 
69