Source Code for Module gofer.rmi.criteria

  1  # Copyright (c) 2012 Red Hat, Inc. 
  2  # 
  3  # This software is licensed to you under the GNU General Public 
  4  # License as published by the Free Software Foundation; either version 
  5  # 2 of the License (GPLv2) or (at your option) any later version. 
  6  # There is NO WARRANTY for this software, express or implied, 
  7  # including the implied warranties of MERCHANTABILITY, 
  8  # NON-INFRINGEMENT, or FITNESS FOR A PARTICULAR PURPOSE. You should 
  9  # have received a copy of GPLv2 along with this software; if not, see 
 10  # http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt. 
 11   
 12   
 13 -class InvalidOperator(Exception): 
 14      pass 
 15   
 16   
 17 -class Criteria: 
 18      """ 
 19      The criteria used to match on an RMI locator. 
 20      """ 
 21   
 22 -    def __init__(self, criteria): 
 23          """ 
 24          @param criteria: The data used for matching. 
 25          @type criteria: object 
 26          """ 
 27          self.criteria = criteria 
 28   
 29 -    def match(self, locator): 
 30          """ 
 31          Match on the specified criteria. 
 32          @param locator: RMI request locator information. 
 33          @type locator: object 
 34          @return: True on match. 
 35          @rtype: bool 
 36          """ 
 37          raise NotImplementedError() 
 38   
 39   
 40 -class Equal(Criteria): 
 41   
 42 -    def match(self, locator): 
 43          return locator == self.criteria 
 44   
 45   
 46 -class NotEqual(Criteria): 
 47   
 48 -    def match(self, locator): 
 49          return locator != self.criteria 
 50   
 51   
 52 -class Greater(Criteria): 
 53   
 54 -    def match(self, locator): 
 55          return locator > self.criteria 
 56   
 57   
 58 -class Less(Criteria): 
 59   
 60 -    def match(self, locator): 
 61          return locator < self.criteria 
 62   
 63   
 64 -class In(Criteria): 
 65   
 66 -    def match(self, locator): 
 67          return locator in self.criteria 
 68   
 69   
 70 -class And(Criteria): 
 71   
 72 -    def match(self, locator): 
 73          left, right = self.criteria 
 74          return left.match(locator) and right.match(locator) 
 75   
 76   
 77 -class Or(Criteria): 
 78   
 79 -    def match(self, locator): 
 80          left, right = self.criteria 
 81          return left.match(locator) or right.match(locator) 
 82   
 83   
 84 -class Builder: 
 85      """ 
 86      Build a criteria object graph based on dictionary representations. 
 87      These representations can be nested. 
 88      Examples: 
 89        {'eq':10} 
 90        {'neq':10} 
 91        {'in':[1,2]} 
 92        {'gt':10} 
 93        {'lt':10} 
 94        {'and':({'gt':1},{'lt':10})} 
 95        {'or':({'eq':10},{'in':[1,2]})} 
 96        {'or':({'eq':10},{'or':({'eq':1},{'eq':2})} 
 97      """ 
 98   
 99      METHODS = { 
100          'eq':Equal, 
101          'neq':NotEqual, 
102          'in':In, 
103          'gt':Greater, 
104          'lt':Less, 
105          'and':And, 
106          'or':Or, 
107      } 
108   
109 -    def build(self, criteria): 
110          """ 
111          Build a L{Criteria} object based on the specified 
112          dict representation. 
113          @param criteria: The criteria to build. 
114          @type criteria: dict 
115          @rtype: L{Criteria} 
116          @raise Exception, on invalid criteria. 
117          """ 
118          for k, v in criteria.items(): 
119              if self._criteria(v): 
120                  v = self._resolve(v) 
121              m = self.METHODS.get(k) 
122              if m: 
123                  return m(self._resolve(v)) 
124              else: 
125                  raise InvalidOperator, '%s not supported' % k 
126   
127 -    def _resolve(self, object): 
128          if self._criteria(object): 
129              return self.build(object) 
130          if isinstance(object, (list,tuple)) and len(object) == 2: 
131              left, right = object 
132              if self._criteria(left) and self._criteria(right): 
133                  left = self.build(left) 
134                  right = self.build(right) 
135                  return (left, right) 
136          return object 
137   
138 -    def _criteria(self, object): 
139          if isinstance(object, dict): 
140              for k in self.METHODS: 
141                  if k in object: 
142                      return True 
143          return False 
144