[Zope-dev] large PersistentMapping

[Chris Withers]

Talk to Tres Seaver about the observer interface and the event channel
stuff.

He has lots of ideas about this and I think it does pretty much what you
want...

cheers,

Chris

Robin Becker wrote:
> 
> I'm trying to build a Reverse Cross Referencing Product. The idea is to
> enable documents to know which other documents in the Zope data base are
> pointing at them.
> I would like to use a persistent mapping to store the link information,
> but since eventually the object might be quite large will I get a
> performance hit when accessing only a small part of the object.
> 
> It certainly seems to work for small instances, but I'm worried about
> what happens as my structure gets larger. Is there an alternate way to
> do this?
> 
> The heart of the object are the methods
> 
> 
>         def __init__(self, id, title):
>                 '''Initialise a new instance of RXRef'''
>                 self.id=str(id)
>                 self.title = str(title)
>                 self.title = title
>                 self._N = PersistentMapping()
> 
>         def addNode(self,n):
>                 '''Add a new node if not known'''
>                 N = self._N
>                 if not N.has_key(n): N[n]=[]
> 
>         def addLinks(self,src,DST):
>                 '''We have a single src and multiple destinations'''
>                 if type(DST) not in SEQTYPES: DST = [DST]
>                 N = self._N
>                 for dst in DST:
>                         self.addNode(dst)
>                         if src not in N[dst]: N[dst].append(src)
> 
>         def delLinks(self,src,DST):
>                 '''We have a single src and multiple destinations'''
>                 if type(DST) not in SEQTYPES: DST = [DST]
>                 N = self._N
>                 for dst in DST:
>                         if N.has_key(dst):
>                                 if src in N[dst]:
>                                         N[dst].remove(src)
>                                         if N[dst]==[]: del N[dst]
> 
>         def getRLinks(self,dst):
>                 '''get links pointing to dst'''
>                 N = self._N
>                 return N.has_key(dst) and N[dst][:] or []
> 
> --
> Robin Becker
> 
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