Mercurial > parpg-source
diff grease/component/base.py @ 5:bc88f7d5ca8b
Added base files for grease
author | KarstenBock@gmx.net |
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date | Tue, 12 Jul 2011 10:16:48 +0200 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/grease/component/base.py Tue Jul 12 10:16:48 2011 +0200 @@ -0,0 +1,74 @@ +class ComponentBase(object): + """Component abstract base class + + Strictly speaking you do not need to derive from this class to create your + own components, but it does serve to document the full interface that a + component implements and it provides some basic implementations for + certain methods + """ + + ## Optional attributes and methods ## + + def set_manager(self, manager): + """Set the manager of this component. If this method exists it will be + automatically called when the component is added to a manager. + + This method stores the manager and allows the component to be added + only once to a single manager. + """ + assert getattr(self, 'manager', None) is None, 'Component cannot be added to multiple managers' + self.manager = manager + + def __del__(self): + """Break circrefs to allow faster collection""" + if hasattr(self, 'manager'): + del self.manager + + ## Mandatory methods ## + + def add(self, entity_id, data=None, **data_kw): + """Add a data entry in the component for the given entity. Additional + data (if any) for the entry can be provided in the data argument or as + keyword arguments. Additional data is optional and if omitted then + suitable defaults will be used. Return an entity data object + for the new entity entry. + + The semantics of the data arguments is up to the component. + + An entity_id is a unique key, thus multiple separate data entries for + a given entity are not allowed. Components can indivdually decide + what to do if an entity_id is added multiple times to the component. + Potential options include, raising an exception, replacing the + existing data or coalescing it somehow. + """ + + def remove(self, entity_id): + """Remove the entity data entry from the component. If the + entity is not in the component, raise KeyError + """ + + def __delitem_(self, entity_id): + """Same as remove()""" + + def __len__(self): + """Return the number of entities in the component""" + raise NotImplementedError() + + def __iter__(self): + """Return an iterator of entity data objects in this component + + No order is defined for these data objects + """ + raise NotImplementedError() + + def __contains__(self, entity_id): + """Return True if the entity is contained in the component""" + raise NotImplementedError() + + def __getitem__(self, entity_id): + """Return the entity data object for the given entity. + The entity data object returned may be mutable, immutable or a + mutable copy of the data at the discretion of the component + """ + raise NotImplementedError() +