pli/pattern/store/storeproxy.py

   1 #=======================================================================
   2
   3 __version__ = '''0.0.05'''
   4 __sub_version__ = '''20040909234325'''
   5 __copyright__ = '''(c) Alex A. Naanou 2003'''
   6
   7
   8 #-----------------------------------------------------------------------
   9
  10 import pli.pattern.store as store
  11
  12
  13 #-----------------------------------------------------------------------
  14 ##!! revise !!##
  15 #------------------------------------------------------BaseStoreProxy---
  16 SAFE_TRNSFER=0
  17 FORCE_OVERWRITE=1
  18 # this stop the overwriting of data in the target backend...
  19 IGNORE_OVERWRITE=2
  20
  21 class BaseStoreProxy(store.BaseStore):
  22         '''
  23         '''
  24 ##      def __init__(self, name, backend=None):
  25 ##              '''
  26 ##              '''
  27 ##              super(BaseStoreProxy, self).__init__(name)
  28 ##              if backend != None:
  29 ##                      self._store_data = backend
  30         def _setbackend(self, backend):
  31                 '''
  32                 '''
  33                 self._store_data = backend
  34
  35         def getbackend(self):
  36                 '''
  37                 '''
  38                 return self._store_data
  39         def changebackend(self, backend, flags=SAFE_TRNSFER):
  40                 '''
  41                 this will transfer data from the current backend to the new.
  42                 '''
  43                 # check for store intersections...
  44                 from_keys = self.keys()
  45                 to_keys = backend.keys()
  46                 if len(from_keys) + len(to_keys) != len(dict.fromkeys(from_keys + to_keys)):
  47                         if flags == 0:
  48                                 ##!!!
  49                                 raise TypeError, 'both the curent store (%s) and the new backend (%s) have matching keys.' % (self, backend)
  50                 for k, v in self.iteritems():
  51                         if k in backend:
  52                                 # sanity check...
  53                                 if flags & SAFE_TRNSFER:
  54                                         ##!!! fatal... (data changed during transfer)
  55                                         raise TypeError, 'data changed during transfer of store %s to %s.' % (self, backend)
  56                                 if flags & FORCE_OVERWRITE:
  57                                         pass
  58                                 elif flags & IGNORE_OVERWRITE:
  59                                         continue
  60                         backend[k] = v
  61                 self._setbackend(backend)
  62
  63
  64
  65 #=======================================================================
  66 #                                            vim:set ts=4 sw=4 nowrap :