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# Copyright (c) 2004 by Intevation GmbH |
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# Authors: |
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# Martin Schulze <[email protected]> |
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# |
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# This program is free software; you can redistribute it and/or modify |
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# it under the terms of the GNU General Public License as published by |
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# the Free Software Foundation; either version 2 of the License, or |
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# (at your option) any later version. |
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# |
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# This program is distributed in the hope that it will be useful, |
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# but WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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# GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with this program; if not, write to the Free Software |
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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|
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""" |
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The provided class maintains a mapping between classes and objects. |
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Instances of the class are used as keys, not classes, though. |
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Usually layer classes and their instances are used in combination with |
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layer property dialog classes in order to utilise the proper dialog |
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for a given layer instance. |
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|
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""" |
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__version__ = "$Revision$" |
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# $Source$ |
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# $Id$ |
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|
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|
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class ClassMapper: |
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""" |
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Thuban class to implement a mapping of classes and objects, |
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usually also classes. |
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""" |
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mapping = None |
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|
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def __init__(self): |
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""" |
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Initialises a mapping. |
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""" |
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self.mapping = [] |
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def add(self, key_class, obj): |
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""" |
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Register an object with a class. |
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This method adds the provided pair (key_class,obj) to the |
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internal list. Subsequently instances of key_class are used |
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to retrieved the stored object. |
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""" |
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self.mapping.append((key_class, obj)) |
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def get(self, instance): |
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""" |
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Retrieve a stored object corresponding to the provided class |
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instance. |
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""" |
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for key_class, obj in self.mapping: |
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if isinstance(instance, key_class): |
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return obj |
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return None |
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def has(self, instance): |
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""" |
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Determine if the ClassMapper contains an object corresponding |
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to the provided instance |
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""" |
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return self.get(instance) is not None |
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