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# -*- coding: utf-8 -*-
#
# This file is part of Linux Show Player
#
# Copyright 2012-2016 Francesco Ceruti <ceppofrancy@gmail.com>
#
# Linux Show Player is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Linux Show Player is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Linux Show Player. If not, see <http://www.gnu.org/licenses/>.
from abc import abstractmethod
from lisp.core.model import Model, ModelException
class ProxyModel(Model):
"""Proxy that wrap a more generic model to extend its functionality.
The add, remove, __iter__, __len__ and __contains__ default implementations
use the the model ones.
.. note:
The base model cannot be changed.
Any ProxyModel could provide it's own methods/signals.
"""
def __init__(self, model):
super().__init__()
if not isinstance(model, Model):
raise TypeError('ProxyModel model must be a Model object, not {0}'
.format(model.__class__.__name__))
self.__model = model
self.__model.item_added.connect(self._item_added)
self.__model.item_removed.connect(self._item_removed)
self.__model.model_reset.connect(self._model_reset)
def add(self, item):
self.__model.add(item)
def remove(self, item):
self.__model.remove(item)
def reset(self):
self.__model.reset()
@property
def model(self):
return self.__model
@abstractmethod
def _model_reset(self):
pass
@abstractmethod
def _item_added(self, item):
pass
@abstractmethod
def _item_removed(self, item):
pass
def __iter__(self):
return self.__model.__iter__()
def __len__(self):
return len(self.__model)
def __contains__(self, item):
return item in self.__model
class ReadOnlyProxyModel(ProxyModel):
def add(self, item):
raise ModelException('cannot add items into a read-only model')
def remove(self, item):
raise ModelException('cannot remove items from a read-only model')
def reset(self):
raise ModelException('cannot reset read-only model')
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