Source Code for Module ndg.xacml.core.condition

 1  """NDG XACML Condition type definition 
 2   
 3  NERC DataGrid 
 4  """ 
 5  __author__ = "P J Kershaw" 
 6  __date__ = "25/02/10" 
 7  __copyright__ = "(C) 2010 Science and Technology Facilities Council" 
 8  __contact__ = "Philip.Kershaw@stfc.ac.uk" 
 9  __license__ = "BSD - see LICENSE file in top-level directory" 
10  __contact__ = "Philip.Kershaw@stfc.ac.uk" 
11  __revision__ = "$Id: condition.py 7955 2011-12-21 18:29:45Z rwilkinson $" 
12  from ndg.xacml.core import XacmlCoreBase 
13  from ndg.xacml.core.expression import Expression 
14   
15   
16 -class Condition(XacmlCoreBase): 
17      """XACML 2.0 Rule Condition Note the difference to XACML 1.0: the Condition  
18      element is its own type and not an Apply type.  It expects a single  
19      Expression derived type child element 
20   
21      @cvar ELEMENT_LOCAL_NAME: XML local name for this element 
22      @type ELEMENT_LOCAL_NAME: string 
23   
24      @cvar APPLY_ELEMENT_LOCAL_NAME: XML local name for the apply element 
25      @type APPLY_ELEMENT_LOCAL_NAME: string 
26   
27      @ivar __expression: expression in this condition 
28      @type __expression: ndg.xacml.core.expression.Expression 
29      """ 
30      ELEMENT_LOCAL_NAME = 'Condition' 
31      APPLY_ELEMENT_LOCAL_NAME = 'Apply' 
32       
33      __slots__ = ('__expression', ) 
34       
35 -    def __init__(self): 
36          super(Condition, self).__init__() 
37          self.__expression = None 
38           
39      @property 
40 -    def expression(self): 
41          """Get expression 
42           
43          @return: expression for this condition 
44          @rtype: ndg.xacml.core.expression.Expression / NoneType 
45          """ 
46          return self.__expression 
47           
48      @expression.setter 
49 -    def expression(self, value): 
50          """Set expression 
51           
52          @param value: expression for this condition 
53          @type value: ndg.xacml.core.expression.Expression 
54          @raise TypeError: incorrect input type set 
55          """ 
56          if not isinstance(value, Expression): 
57              raise TypeError('Expecting Expression or Expression derived type ' 
58                              'for "expression" attribute; got %r' % 
59                              type(value)) 
60          self.__expression = value 
61       
62 -    def evaluate(self, context): 
63          """Evaluate this rule condition 
64          @param context: the request context 
65          @type context: ndg.xacml.core.request.Request 
66          @return: True/False status for whether the rule condition matched or 
67          not 
68          @rtype: bool 
69          """ 
70          result = self.expression.evaluate(context) 
71           
72          return result 
73