Source Code for Module ndg.xacml.core.functions.v1.and

 1  """NDG XACML one and only functions module 
 2   
 3  NERC DataGrid 
 4  """ 
 5  __author__ = "P J Kershaw" 
 6  __date__ = "01/04/10" 
 7  __copyright__ = "" 
 8  __license__ = "BSD - see LICENSE file in top-level directory" 
 9  __contact__ = "Philip.Kershaw@stfc.ac.uk" 
10  __revision__ = '$Id$' 
11  from ndg.xacml.core.functions import (AbstractFunction,  
12                                        FunctionClassFactoryInterface) 
13  from ndg.xacml.core.context.exceptions import XacmlContextTypeError 
14   
15   
16 -class And(AbstractFunction): 
17      """Base class for XACML <type>-and functions 
18       
19      @cvar FUNCTION_NS: namespace for this function 
20      @type FUNCTION_NS: string 
21      @cvar ATTRIBUTE_TYPE: type for arguments 
22      @type ATTRIBUTE_TYPE: str 
23      """ 
24      FUNCTION_NS = AbstractFunction.V1_0_FUNCTION_NS + 'and' 
25      ATTRIBUTE_TYPE = bool 
26       
27 -    def evaluate(self, *args): 
28          """perform AND function on the variable length argument list of elements 
29   
30          access_control-xacml-2.0-core-spec-os, Fe 2005 - A.3.5 Logical functions 
31          access_control-xacml-2.0-core-spec-os, Fe 2005 - 4.2.4.2 ( Rule 2 a[346] ... a[361] ) 
32          @param *args: variable number of elements to be AND'ed 
33          @type bool: ndg.xacml.utils.TypedList 
34   
35          @return: result of AND operation on the inputs 
36          @rtype: bool 
37          """ 
38          if len(args)==0: 
39              return True 
40          else: 
41              for n, arg in enumerate(args): 
42                  if type(arg) != self.__class__.ATTRIBUTE_TYPE: 
43                      raise XacmlContextTypeError( 
44                                  'Expecting %r type for attribute %d; got %r' % 
45                                  (self.__class__.ATTRIBUTE_TYPE, n + 1, 
46                                   type(arg))) 
47              for arg in args: 
48                  if not arg: 
49                      return False 
50          return True 
51   
52   
53 -class FunctionClassFactory(FunctionClassFactoryInterface): 
54      """Class Factory for and XACML function class 
55       
56      @cvar FUNCTION_NS: URN for and function 
57      @type FUNCTION_NS: string 
58      """ 
59      FUNCTION_NS = 'urn:oasis:names:tc:xacml:1.0:function:and' 
60       
61 -    def __call__(self, identifier): 
62          '''Create class for the And XACML function identifier 
63           
64          @param identifier: XACML and function identifier 
65          @type identifier: basestring 
66          @return: and function class or None if identifier doesn't match 
67          @rtype: ndg.xacml.core.functions.v1.and.And / NoneType 
68          ''' 
69          if identifier == And.FUNCTION_NS: 
70              return And 
71          else: 
72              return None 
73