Package twisted :: Package popsicle |
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## Package twisted.popsicle

Persistent Object Partitioning Strategy Involving Concurrent Lightweight Events

POPSICLE is designed to persist objects as close to transparently as possible. While complete transparency is impossible with python's semantics, popsicle strives to preserve three things:

1. preserve a modicum of referential transparency by using Deferreds for all references which can not (or should not!) be immediately resolved
2. allow for the use of multiple persistence strategies with the same object. Specific back-ends we wish to target: filesystem databases, BSDDB, ReiserFS, ZODB, and arbitrary RDBMS schemas.
3. minimize memory usage by paging unnecessary objects out whenever possible, transparently to everything involved. We want to use Python's normal garbage collection mechanisms to accomplish this.

There is a top level persistence manager (the 'freezer') which keeps a weak key dictionary of {persistent_object: [PersistentReference, [savers]]}

The persistent_object should be 'trained' to expect callable objects that return Deferreds to populate part of it. Whenever a persistence mechanism encounters an ID for a different object that could be loaded...

Each Storage is responsible for its own cache management wrt IDs.

Objects that are dirty should call popsicle.dirty(self) to be added to the dirty list. when popsicle.clean() is called, the dirty list will be walked, notifying all savers for each dirty object.

### Modules

- `freezer`
- `mailsicle`: Mailsicle
- `picklesicle`: This is code and support for
- `repos`: Abstract Repository classes for Popsicle.

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