Source Code for Module occi.backend

  1  # coding=utf-8 
  2  # 
  3  # Copyright (C) 2010-2012 Platform Computing 
  4  # 
  5  # This library is free software; you can redistribute it and/or 
  6  # modify it under the terms of the GNU Lesser General Public 
  7  # License as published by the Free Software Foundation; either 
  8  # version 2.1 of the License, or (at your option) any later version. 
  9  # 
 10  # This library is distributed in the hope that it will be useful, 
 11  # but WITHOUT ANY WARRANTY; without even the implied warranty of 
 12  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
 13  # Lesser General Public License for more details. 
 14  # 
 15  # You should have received a copy of the GNU Lesser General Public 
 16  # License along with this library; if not, write to the Free Software 
 17  # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA 
 18  # 
 19  ''' 
 20  Backends should derive from this class. 
 21   
 22  Created on Jun 27, 2011 
 23   
 24  @author: tmetsch 
 25  ''' 
 26   
 27   
 28 -def is_related_valid(link): 
 29      ''' 
 30      Verifies that a link is consistent. 
 31   
 32      link -- The link which should be verified. 
 33      ''' 
 34      if link.target.kind == link.kind.related: 
 35          return True 
 36      else: 
 37          return False 
 38   
 39   
 40 -def is_attr_mutable(category, attribute_name): 
 41      ''' 
 42      Checks if an attribute is mutable. Return True if so. 
 43   
 44      category -- The category which defines the attribute. 
 45      attribute_name -- The name of the attribute. 
 46      ''' 
 47      if category.attributes[attribute_name] == 'mutable': 
 48          return True 
 49      else: 
 50          return False 
 51   
 52   
 53 -def is_attr_required(category, attribute_name): 
 54      ''' 
 55      Checks if an attribute is required. Return True if so. 
 56   
 57      category -- The category which defines the attribute. 
 58      attribute_name -- The name of the attribute. 
 59      ''' 
 60      if category.attributes[attribute_name] == 'required': 
 61          return True 
 62      else: 
 63          return False 
 64   
 65   
 66 -def is_action_applicable(entity, action): 
 67      ''' 
 68      Returns true if the action is currently applicable. 
 69   
 70      entity -- The current entity. 
 71      action -- The action to test for. 
 72      ''' 
 73      if action in entity.actions and action in entity.kind.actions: 
 74          return True 
 75      else: 
 76          return False 
 77   
 78   
 79 -class KindBackend(object): 
 80      ''' 
 81      A prototype backend which essentially does nothing. 
 82   
 83      Use this Backend for your Resource and Link types. 
 84   
 85      Note that it can happen that an entity has more than one backend assigned 
 86      (this is the case when it has a couple of mixins). But you can assign 
 87      multiple kinds to one backend. 
 88      ''' 
 89   
 90 -    def create(self, entity, extras): 
 91          ''' 
 92          Call the Resource Management and create this entity. 
 93   
 94          entity -- The entity which is to be created. 
 95          extras -- Any extra arguments which are defined by the user. 
 96          ''' 
 97          pass 
 98   
 99 -    def retrieve(self, entity, extras): 
100          ''' 
101          Call the Resource Management and refresh this entity so the client gets 
102          up to date information. 
103   
104          entity -- The entity which is to be retrieved. 
105          extras -- Any extra arguments which are defined by the user. 
106          ''' 
107          pass 
108   
109 -    def update(self, old, new, extras): 
110          ''' 
111          Call the Resource Management and update this entity. 
112   
113          It is up to the backend implementation to decide which information from 
114          new if copied into old. 
115   
116          Note that the new entity might no have all the information the old one 
117          had. 
118   
119          old -- The old entity which is to be updated. 
120          new -- The new entity holding the updated information. 
121          extras -- Any extra arguments which are defined by the user. 
122          ''' 
123          pass 
124   
125 -    def replace(self, old, new, extras): 
126          ''' 
127          Call the Resource Management and update this entity. This is 
128          essentially a full update (Which allows removal of attributes for 
129          example). 
130   
131          It is up to the backend implementation to decide which information from 
132          new if copied into old. So if you really want to replace old with new 
133          you need to have an old.* = new.* somewhere here (RECOMMENDED). 
134   
135          old -- The old entity which is to be updated. 
136          new -- The new entity holding the updated information. 
137          extras -- Any extra arguments which are defined by the user. 
138          ''' 
139          pass 
140   
141 -    def delete(self, entity, extras): 
142          ''' 
143          Call the Resource Management and delete this entity. 
144   
145          entity -- The entity which is to be deleted. 
146          extras -- Any extra arguments which are defined by the user. 
147          ''' 
148          pass 
149   
150   
151 -class ActionBackend(object): 
152      ''' 
153      A prototype backend which essentially does nothing. 
154   
155      Use this Backend for Action types. 
156      ''' 
157   
158      # disabling 'Too few public...' pylint check (this is for extension) 
159      # pylint: disable=R0903 
160   
161 -    def action(self, entity, action, attributes, extras): 
162          ''' 
163          Call the Resource Management and perform this action. 
164   
165          entity -- The entity on which the action is going to be performed. 
166          action -- The action category definition. 
167          attributes -- The acctributes for this action. 
168          extras -- Any extra arguments which are defined by the user. 
169          ''' 
170          pass 
171   
172   
173 -class MixinBackend(KindBackend): 
174      ''' 
175      A prototype backend which essentially does nothing. 
176   
177      Use this Backend for Mixin types. 
178      ''' 
179   
180      pass 
181   
182   
183 -class UserDefinedMixinBackend(MixinBackend): 
184      ''' 
185      A Backend for mixins defined by users. 
186   
187      DO NOT USE THIS CLASS IN YOUR IMPLEMENTATION! 
188      ''' 
189   
190      pass 
191