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

 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: one_and_only.py 7087 2010-06-25 11:23:09Z pjkersha $' 
11  #from datetime import datetime, timedelta 
12   
13  from ndg.xacml.core.functions import AbstractFunction, FunctionClassFactoryBase 
14  from ndg.xacml.utils import TypedList as Bag 
15  from ndg.xacml.core.context.exceptions import XacmlContextError 
16   
17   
18 -class OneAndOnlyBase(AbstractFunction): 
19      """Base class for XACML <type>-one-and-only functions 
20       
21      @cvar TYPE: attribute type for the given implementation.  Derived classes 
22      should set appropriately 
23      @type TYPE: NoneType 
24      """ 
25      TYPE = None 
26       
27 -    def evaluate(self, bag): 
28          """Check a bag has one element only and return it 
29           
30          @param bag: bag containing one element 
31          @type bag: ndg.xacml.utils.TypedList 
32          @return: single item from bag 
33          @rtype: dependent on bag type set in derived type 
34          """ 
35          if not isinstance(bag, Bag): 
36              raise XacmlContextError('Expecting %r derived type for "bag"; ' 
37                                      'got %r' % (Bag, type(bag))) 
38               
39          if bag.elementType != self.__class__.TYPE: 
40              raise XacmlContextError('Expecting %r type elements for "bag"; ' 
41                                      'got %r' % 
42                                      (self.__class__.TYPE, bag.elementType)) 
43                           
44          nBagElems = len(bag) 
45          if nBagElems != 1: 
46              raise XacmlContextError('Expecting single element for %r bag; got ' 
47                                      '%r' % (self.__class__.TYPE, nBagElems)) 
48               
49          return bag[0] 
50       
51   
52 -class FunctionClassFactory(FunctionClassFactoryBase): 
53      """Class Factory for *-one-and-only XACML function classes 
54       
55      @cvar FUNCTION_NAMES: one and only function URNs 
56      @type FUNCTION_NAMES: tuple 
57       
58      @cvar FUNCTION_NS_SUFFIX: generic suffix for one and only function URNs 
59      @type FUNCTION_NS_SUFFIX: string 
60       
61      @cvar FUNCTION_BASE_CLASS: base class for all one and only function classes  
62      @type FUNCTION_BASE_CLASS: ndg.xacml.core.functions.v1.OneAndOnlyBase 
63      """ 
64      FUNCTION_NAMES = ( 
65          'urn:oasis:names:tc:xacml:1.0:function:string-one-and-only', 
66          'urn:oasis:names:tc:xacml:1.0:function:boolean-one-and-only', 
67          'urn:oasis:names:tc:xacml:1.0:function:integer-one-and-only', 
68          'urn:oasis:names:tc:xacml:1.0:function:double-one-and-only', 
69          'urn:oasis:names:tc:xacml:1.0:function:time-one-and-only', 
70          'urn:oasis:names:tc:xacml:1.0:function:date-one-and-only', 
71          'urn:oasis:names:tc:xacml:1.0:function:dateTime-one-and-only', 
72          'urn:oasis:names:tc:xacml:1.0:function:anyURI-one-and-only', 
73          'urn:oasis:names:tc:xacml:1.0:function:hexBinary-one-and-only', 
74          'urn:oasis:names:tc:xacml:1.0:function:base64Binary-one-and-only', 
75          'urn:oasis:names:tc:xacml:1.0:function:dayTimeDuration-one-and-only', 
76          'urn:oasis:names:tc:xacml:1.0:function:yearMonthDuration-one-and-only', 
77          'urn:oasis:names:tc:xacml:1.0:function:x500Name-one-and-only', 
78          'urn:oasis:names:tc:xacml:1.0:function:rfc822Name-one-and-only' 
79      ) 
80      FUNCTION_NS_SUFFIX = '-one-and-only' 
81      FUNCTION_BASE_CLASS = OneAndOnlyBase 
82