Mercurial > parpg-source
comparison grease/component/base.py @ 5:bc88f7d5ca8b
Added base files for grease
| author | KarstenBock@gmx.net |
|---|---|
| date | Tue, 12 Jul 2011 10:16:48 +0200 |
| parents | |
| children |
comparison
equal
deleted
inserted
replaced
| 4:bf1dd9c24a7e | 5:bc88f7d5ca8b |
|---|---|
| 1 class ComponentBase(object): | |
| 2 """Component abstract base class | |
| 3 | |
| 4 Strictly speaking you do not need to derive from this class to create your | |
| 5 own components, but it does serve to document the full interface that a | |
| 6 component implements and it provides some basic implementations for | |
| 7 certain methods | |
| 8 """ | |
| 9 | |
| 10 ## Optional attributes and methods ## | |
| 11 | |
| 12 def set_manager(self, manager): | |
| 13 """Set the manager of this component. If this method exists it will be | |
| 14 automatically called when the component is added to a manager. | |
| 15 | |
| 16 This method stores the manager and allows the component to be added | |
| 17 only once to a single manager. | |
| 18 """ | |
| 19 assert getattr(self, 'manager', None) is None, 'Component cannot be added to multiple managers' | |
| 20 self.manager = manager | |
| 21 | |
| 22 def __del__(self): | |
| 23 """Break circrefs to allow faster collection""" | |
| 24 if hasattr(self, 'manager'): | |
| 25 del self.manager | |
| 26 | |
| 27 ## Mandatory methods ## | |
| 28 | |
| 29 def add(self, entity_id, data=None, **data_kw): | |
| 30 """Add a data entry in the component for the given entity. Additional | |
| 31 data (if any) for the entry can be provided in the data argument or as | |
| 32 keyword arguments. Additional data is optional and if omitted then | |
| 33 suitable defaults will be used. Return an entity data object | |
| 34 for the new entity entry. | |
| 35 | |
| 36 The semantics of the data arguments is up to the component. | |
| 37 | |
| 38 An entity_id is a unique key, thus multiple separate data entries for | |
| 39 a given entity are not allowed. Components can indivdually decide | |
| 40 what to do if an entity_id is added multiple times to the component. | |
| 41 Potential options include, raising an exception, replacing the | |
| 42 existing data or coalescing it somehow. | |
| 43 """ | |
| 44 | |
| 45 def remove(self, entity_id): | |
| 46 """Remove the entity data entry from the component. If the | |
| 47 entity is not in the component, raise KeyError | |
| 48 """ | |
| 49 | |
| 50 def __delitem_(self, entity_id): | |
| 51 """Same as remove()""" | |
| 52 | |
| 53 def __len__(self): | |
| 54 """Return the number of entities in the component""" | |
| 55 raise NotImplementedError() | |
| 56 | |
| 57 def __iter__(self): | |
| 58 """Return an iterator of entity data objects in this component | |
| 59 | |
| 60 No order is defined for these data objects | |
| 61 """ | |
| 62 raise NotImplementedError() | |
| 63 | |
| 64 def __contains__(self, entity_id): | |
| 65 """Return True if the entity is contained in the component""" | |
| 66 raise NotImplementedError() | |
| 67 | |
| 68 def __getitem__(self, entity_id): | |
| 69 """Return the entity data object for the given entity. | |
| 70 The entity data object returned may be mutable, immutable or a | |
| 71 mutable copy of the data at the discretion of the component | |
| 72 """ | |
| 73 raise NotImplementedError() | |
| 74 |