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comparison bGrease/component/base.py @ 41:ff3e395abf91

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Renamed grease to bGrease (Basic Grease) to get rid of conflicts with an already installed grease.
author KarstenBock@gmx.net
date Mon, 05 Sep 2011 15:00:34 +0200
parents grease/component/base.py@bc88f7d5ca8b
children a6bbb732b27b
comparison
equal deleted inserted replaced
40:2e3ab06a2f47 41:ff3e395abf91
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